src/share/classes/java/nio/file/Files.java
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@@ -23,29 +23,1453 @@
* questions.
*/
package java.nio.file;
-import java.nio.file.spi.FileTypeDetector;
import java.nio.file.attribute.*;
-import java.io.IOException;
+import java.nio.file.spi.FileSystemProvider;
+import java.nio.file.spi.FileTypeDetector;
+import java.nio.channels.SeekableByteChannel;
+import java.io.*;
import java.util.*;
import java.security.AccessController;
import java.security.PrivilegedAction;
+import java.nio.charset.*;
/**
- * This class consists exclusively of static methods that operate on files or
- * directories.
+ * This class consists exclusively of static methods that operate on files,
+ * directories, or other types of files.
*
+ * <p> In most cases, the methods defined here will delegate to the associated
+ * file system provider to perform the file operations.
+ *
* @since 1.7
*/
public final class Files {
private Files() { }
+ /**
+ * Returns the {@code FileSystemProvider} to delegate to.
+ */
+ private static FileSystemProvider provider(Path path) {
+ return path.getFileSystem().provider();
+ }
+
+ // -- File contents --
+
+ /**
+ * Opens a file, returning an input stream to read from the file. The stream
+ * will not be buffered, and is not required to support the {@link
+ * InputStream#mark mark} or {@link InputStream#reset reset} methods. The
+ * stream will be safe for access by multiple concurrent threads. Reading
+ * commences at the beginning of the file. Whether the returned stream is
+ * <i>asynchronously closeable</i> and/or <i>interruptible</i> is highly
+ * file system provider specific and therefore not specified.
+ *
+ * <p> The {@code options} parameter determines how the file is opened.
+ * If no options are present then it is equivalent to opening the file with
+ * the {@link StandardOpenOption#READ READ} option. In addition to the {@code
+ * READ} option, an implementation may also support additional implementation
+ * specific options.
+ *
+ * @param path
+ * the path to the file to open
+ * @param options
+ * options specifying how the file is opened
+ *
+ * @return a new input stream
+ *
+ * @throws IllegalArgumentException
+ * if an invalid combination of options is specified
+ * @throws UnsupportedOperationException
+ * if an unsupported option is specified
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file.
+ */
+ public static InputStream newInputStream(Path path, OpenOption... options)
+ throws IOException
+ {
+ return provider(path).newInputStream(path, options);
+ }
+
+ /**
+ * Opens or creates a file, returning an output stream that may be used to
+ * write bytes to the file. The resulting stream will not be buffered. The
+ * stream will be safe for access by multiple concurrent threads. Whether
+ * the returned stream is <i>asynchronously closeable</i> and/or
+ * <i>interruptible</i> is highly file system provider specific and
+ * therefore not specified.
+ *
+ * <p> This method opens or creates a file in exactly the manner specified
+ * by the {@link #newByteChannel(Path,Set,FileAttribute[]) newByteChannel}
+ * method with the exception that the {@link StandardOpenOption#READ READ}
+ * option may not be present in the array of options. If no options are
+ * present then this method works as if the {@link StandardOpenOption#CREATE
+ * CREATE}, {@link StandardOpenOption#TRUNCATE_EXISTING TRUNCATE_EXISTING},
+ * and {@link StandardOpenOption#WRITE WRITE} options are present. In other
+ * words, it opens the file for writing, creating the file if it doesn't
+ * exist, or initially truncating an existing {@link #isRegularFile
+ * regular-file} to a size of {@code 0} if it exists.
+ *
+ * <p> <b>Usage Examples:</b>
+ * <pre>
+ * Path path = ...
+ *
+ * // replace an existing file or create the file if it doesn't initially exist
+ * OutputStream out = Files.newOutputStream(path);
+ *
+ * // append to an existing file, fail if the file does not exist
+ * out = Files.newOutputStream(path, APPEND);
+ *
+ * // append to an existing file, create file if it doesn't initially exist
+ * out = Files.newOutputStream(CREATE, APPEND);
+ *
+ * // always create new file, failing if it already exists
+ * out = Files.newOutputStream(CREATE_NEW);
+ * </pre>
+ *
+ * @param path
+ * the path to the file to open or create
+ * @param options
+ * options specifying how the file is opened
+ *
+ * @return a new output stream
+ *
+ * @throws IllegalArgumentException
+ * if {@code options} contains an invalid combination of options
+ * @throws UnsupportedOperationException
+ * if an unsupported option is specified
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the file. The {@link
+ * SecurityManager#checkDelete(String) checkDelete} method is
+ * invoked to check delete access if the file is opened with the
+ * {@code DELETE_ON_CLOSE} option.
+ */
+ public static OutputStream newOutputStream(Path path, OpenOption... options)
+ throws IOException
+ {
+ return provider(path).newOutputStream(path, options);
+ }
+
+ /**
+ * Opens or creates a file, returning a seekable byte channel to access the
+ * file.
+ *
+ * <p> The {@code options} parameter determines how the file is opened.
+ * The {@link StandardOpenOption#READ READ} and {@link
+ * StandardOpenOption#WRITE WRITE} options determine if the file should be
+ * opened for reading and/or writing. If neither option (or the {@link
+ * StandardOpenOption#APPEND APPEND} option) is present then the file is
+ * opened for reading. By default reading or writing commence at the
+ * beginning of the file.
+ *
+ * <p> In the addition to {@code READ} and {@code WRITE}, the following
+ * options may be present:
+ *
+ * <table border=1 cellpadding=5 summary="">
+ * <tr> <th>Option</th> <th>Description</th> </tr>
+ * <tr>
+ * <td> {@link StandardOpenOption#APPEND APPEND} </td>
+ * <td> If this option is present then the file is opened for writing and
+ * each invocation of the channel's {@code write} method first advances
+ * the position to the end of the file and then writes the requested
+ * data. Whether the advancement of the position and the writing of the
+ * data are done in a single atomic operation is system-dependent and
+ * therefore unspecified. This option may not be used in conjunction
+ * with the {@code READ} or {@code TRUNCATE_EXISTING} options. </td>
+ * </tr>
+ * <tr>
+ * <td> {@link StandardOpenOption#TRUNCATE_EXISTING TRUNCATE_EXISTING} </td>
+ * <td> If this option is present then the existing file is truncated to
+ * a size of 0 bytes. This option is ignored when the file is opened only
+ * for reading. </td>
+ * </tr>
+ * <tr>
+ * <td> {@link StandardOpenOption#CREATE_NEW CREATE_NEW} </td>
+ * <td> If this option is present then a new file is created, failing if
+ * the file already exists or is a symbolic link. When creating a file the
+ * check for the existence of the file and the creation of the file if it
+ * does not exist is atomic with respect to other file system operations.
+ * This option is ignored when the file is opened only for reading. </td>
+ * </tr>
+ * <tr>
+ * <td > {@link StandardOpenOption#CREATE CREATE} </td>
+ * <td> If this option is present then an existing file is opened if it
+ * exists, otherwise a new file is created. This option is ignored if the
+ * {@code CREATE_NEW} option is also present or the file is opened only
+ * for reading. </td>
+ * </tr>
+ * <tr>
+ * <td > {@link StandardOpenOption#DELETE_ON_CLOSE DELETE_ON_CLOSE} </td>
+ * <td> When this option is present then the implementation makes a
+ * <em>best effort</em> attempt to delete the file when closed by the
+ * {@link SeekableByteChannel#close close} method. If the {@code close}
+ * method is not invoked then a <em>best effort</em> attempt is made to
+ * delete the file when the Java virtual machine terminates. </td>
+ * </tr>
+ * <tr>
+ * <td>{@link StandardOpenOption#SPARSE SPARSE} </td>
+ * <td> When creating a new file this option is a <em>hint</em> that the
+ * new file will be sparse. This option is ignored when not creating
+ * a new file. </td>
+ * </tr>
+ * <tr>
+ * <td> {@link StandardOpenOption#SYNC SYNC} </td>
+ * <td> Requires that every update to the file's content or metadata be
+ * written synchronously to the underlying storage device. (see <a
+ * href="package-summary.html#integrity"> Synchronized I/O file
+ * integrity</a>). </td>
+ * <tr>
+ * <tr>
+ * <td> {@link StandardOpenOption#DSYNC DSYNC} </td>
+ * <td> Requires that every update to the file's content be written
+ * synchronously to the underlying storage device. (see <a
+ * href="package-summary.html#integrity"> Synchronized I/O file
+ * integrity</a>). </td>
+ * </tr>
+ * </table>
+ *
+ * <p> An implementation may also support additional implementation specific
+ * options.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * file-attributes} to set atomically when a new file is created.
+ *
+ * <p> In the case of the default provider, the returned seekable byte channel
+ * is a {@link java.nio.channels.FileChannel}.
+ *
+ * <p> <b>Usage Examples:</b>
+ * <pre>
+ * Path path = ...
+ *
+ * // open file for reading
+ * ReadableByteChannel rbc = Files.newByteChannel(path, EnumSet.of(READ)));
+ *
+ * // open file for writing to the end of an existing file, creating
+ * // the file if it doesn't already exist
+ * WritableByteChannel wbc = Files.newByteChannel(path, EnumSet.of(CREATE,APPEND));
+ *
+ * // create file with initial permissions, opening it for both reading and writing
+ * {@code FileAttribute<<SetPosixFilePermission>> perms = ...}
+ * SeekableByteChannel sbc = Files.newByteChannel(path, EnumSet.of(CREATE_NEW,READ,WRITE), perms);
+ * </pre>
+ *
+ * @param path
+ * the path to the file to open or create
+ * @param options
+ * options specifying how the file is opened
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the file
+ *
+ * @return a new seekable byte channel
+ *
+ * @throws IllegalArgumentException
+ * if the set contains an invalid combination of options
+ * @throws UnsupportedOperationException
+ * if an unsupported open option is specified or the array contains
+ * attributes that cannot be set atomically when creating the file
+ * @throws FileAlreadyExistsException
+ * if a file of that name already exists and the {@link
+ * StandardOpenOption#CREATE_NEW CREATE_NEW} option is specified
+ * <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the path if the file is
+ * opened for reading. The {@link SecurityManager#checkWrite(String)
+ * checkWrite} method is invoked to check write access to the path
+ * if the file is opened for writing. The {@link
+ * SecurityManager#checkDelete(String) checkDelete} method is
+ * invoked to check delete access if the file is opened with the
+ * {@code DELETE_ON_CLOSE} option.
+ *
+ * @see java.nio.channels.FileChannel#open(Path,Set,FileAttribute[])
+ */
+ public static SeekableByteChannel newByteChannel(Path path,
+ Set<? extends OpenOption> options,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ return provider(path).newByteChannel(path, options, attrs);
+ }
+
+ /**
+ * Opens or creates a file, returning a seekable byte channel to access the
+ * file.
+ *
+ * <p> This method opens or creates a file in exactly the manner specified
+ * by the {@link #newByteChannel(Path,Set,FileAttribute[]) newByteChannel}
+ * method.
+ *
+ * @param path
+ * the path to the file to open or create
+ * @param options
+ * options specifying how the file is opened
+ *
+ * @return a new seekable byte channel
+ *
+ * @throws IllegalArgumentException
+ * if the set contains an invalid combination of options
+ * @throws UnsupportedOperationException
+ * if an unsupported open option is specified
+ * @throws FileAlreadyExistsException
+ * if a file of that name already exists and the {@link
+ * StandardOpenOption#CREATE_NEW CREATE_NEW} option is specified
+ * <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the path if the file is
+ * opened for reading. The {@link SecurityManager#checkWrite(String)
+ * checkWrite} method is invoked to check write access to the path
+ * if the file is opened for writing. The {@link
+ * SecurityManager#checkDelete(String) checkDelete} method is
+ * invoked to check delete access if the file is opened with the
+ * {@code DELETE_ON_CLOSE} option.
+ *
+ * @see java.nio.channels.FileChannel#open(Path,OpenOption[])
+ */
+ public static SeekableByteChannel newByteChannel(Path path, OpenOption... options)
+ throws IOException
+ {
+ Set<OpenOption> set = new HashSet<OpenOption>(options.length);
+ Collections.addAll(set, options);
+ return newByteChannel(path, set);
+ }
+
+ // -- Directories --
+
+ /**
+ * Opens a directory, returning a {@link DirectoryStream} to iterate over
+ * all entries in the directory. The elements returned by the directory
+ * stream's {@link DirectoryStream#iterator iterator} are of type {@code
+ * Path}, each one representing an entry in the directory. The {@code Path}
+ * objects are obtained as if by {@link Path#resolve(Path) resolving} the
+ * name of the directory entry against {@code dir}.
+ *
+ * <p> When not using the try-with-resources construct, then directory
+ * stream's {@code close} method should be invoked after iteration is
+ * completed so as to free any resources held for the open directory.
+ *
+ * <p> When an implementation supports operations on entries in the
+ * directory that execute in a race-free manner then the returned directory
+ * stream is a {@link SecureDirectoryStream}.
+ *
+ * @param dir
+ * the path to the directory
+ *
+ * @return a new and open {@code DirectoryStream} object
+ *
+ * @throws NotDirectoryException
+ * if the file could not otherwise be opened because it is not
+ * a directory <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the directory.
+ */
+ public static DirectoryStream<Path> newDirectoryStream(Path dir)
+ throws IOException
+ {
+ return provider(dir).newDirectoryStream(dir, new DirectoryStream.Filter<Path>() {
+ @Override
+ public boolean accept(Path entry) {
+ return true;
+ }
+ });
+ }
+
+ /**
+ * Opens a directory, returning a {@link DirectoryStream} to iterate over
+ * the entries in the directory. The elements returned by the directory
+ * stream's {@link DirectoryStream#iterator iterator} are of type {@code
+ * Path}, each one representing an entry in the directory. The {@code Path}
+ * objects are obtained as if by {@link Path#resolve(Path) resolving} the
+ * name of the directory entry against {@code dir}. The entries returned by
+ * the iterator are filtered by matching the {@code String} representation
+ * of their file names against the given <em>globbing</em> pattern.
+ *
+ * <p> For example, suppose we want to iterate over the files ending with
+ * ".java" in a directory:
+ * <pre>
+ * Path dir = ...
+ * try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir, "*.java")) {
+ * :
+ * }
+ * </pre>
+ *
+ * <p> The globbing pattern is specified by the {@link
+ * FileSystem#getPathMatcher getPathMatcher} method.
+ *
+ * <p> When not using the try-with-resources construct, then directory
+ * stream's {@code close} method should be invoked after iteration is
+ * completed so as to free any resources held for the open directory.
+ *
+ * <p> When an implementation supports operations on entries in the
+ * directory that execute in a race-free manner then the returned directory
+ * stream is a {@link SecureDirectoryStream}.
+ *
+ * @param dir
+ * the path to the directory
+ * @param glob
+ * the glob pattern
+ *
+ * @return a new and open {@code DirectoryStream} object
+ *
+ * @throws java.util.regex.PatternSyntaxException
+ * if the pattern is invalid
+ * @throws NotDirectoryException
+ * if the file could not otherwise be opened because it is not
+ * a directory <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the directory.
+ */
+ public static DirectoryStream<Path> newDirectoryStream(Path dir, String glob)
+ throws IOException
+ {
+ // avoid creating a matcher if all entries are required.
+ if (glob.equals("*"))
+ return newDirectoryStream(dir);
+
+ // create a matcher and return a filter that uses it.
+ FileSystem fs = dir.getFileSystem();
+ final PathMatcher matcher = fs.getPathMatcher("glob:" + glob);
+ DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
+ @Override
+ public boolean accept(Path entry) {
+ return matcher.matches(entry.getFileName());
+ }
+ };
+ return fs.provider().newDirectoryStream(dir, filter);
+ }
+
+ /**
+ * Opens a directory, returning a {@link DirectoryStream} to iterate over
+ * the entries in the directory. The elements returned by the directory
+ * stream's {@link DirectoryStream#iterator iterator} are of type {@code
+ * Path}, each one representing an entry in the directory. The {@code Path}
+ * objects are obtained as if by {@link Path#resolve(Path) resolving} the
+ * name of the directory entry against {@code dir}. The entries returned by
+ * the iterator are filtered by the given {@link DirectoryStream.Filter
+ * filter}.
+ *
+ * <p> When not using the try-with-resources construct, then directory
+ * stream's {@code close} method should be invoked after iteration is
+ * completed so as to free any resources held for the open directory.
+ *
+ * <p> Where the filter terminates due to an uncaught error or runtime
+ * exception then it is propagated to the {@link Iterator#hasNext()
+ * hasNext} or {@link Iterator#next() next} method. Where an {@code
+ * IOException} is thrown, it results in the {@code hasNext} or {@code
+ * next} method throwing a {@link DirectoryIteratorException} with the
+ * {@code IOException} as the cause.
+ *
+ * <p> When an implementation supports operations on entries in the
+ * directory that execute in a race-free manner then the returned directory
+ * stream is a {@link SecureDirectoryStream}.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want to iterate over the files in a directory that are
+ * larger than 8K.
+ * <pre>
+ * DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
+ * public boolean accept(Path file) throws IOException {
+ * return (Files.size(file) > 8192L);
+ * }
+ * };
+ * Path dir = ...
+ * try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir, filter)) {
+ * :
+ * }
+ * </pre>
+ *
+ * @param dir
+ * the path to the directory
+ * @param filter
+ * the directory stream filter
+ *
+ * @return a new and open {@code DirectoryStream} object
+ *
+ * @throws NotDirectoryException
+ * if the file could not otherwise be opened because it is not
+ * a directory <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the directory.
+ */
+ public static DirectoryStream<Path> newDirectoryStream(Path dir,
+ DirectoryStream.Filter<? super Path> filter)
+ throws IOException
+ {
+ return provider(dir).newDirectoryStream(dir, filter);
+ }
+
+ // -- Creation and deletion --
+
+ /**
+ * Creates a new and empty file, failing if the file already exists. The
+ * check for the existence of the file and the creation of the new file if
+ * it does not exist are a single operation that is atomic with respect to
+ * all other filesystem activities that might affect the directory.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * file-attributes} to set atomically when creating the file. Each attribute
+ * is identified by its {@link FileAttribute#name name}. If more than one
+ * attribute of the same name is included in the array then all but the last
+ * occurrence is ignored.
+ *
+ * @param path
+ * the path to the file to create
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the file
+ *
+ * @return the file
+ *
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the file
+ * @throws FileAlreadyExistsException
+ * if a file of that name already exists
+ * <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs or the parent directory does not exist
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the new file.
+ */
+ public static Path createFile(Path path, FileAttribute<?>... attrs)
+ throws IOException
+ {
+ EnumSet<StandardOpenOption> options =
+ EnumSet.of(StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE);
+ SeekableByteChannel sbc = newByteChannel(path, options, attrs);
+ try {
+ sbc.close();
+ } catch (IOException x) {
+ // ignore the IOException as otherwise the method would fail
+ // after creating the file.
+ }
+ return path;
+ }
+
+ /**
+ * Creates a new directory. The check for the existence of the file and the
+ * creation of the directory if it does not exist are a single operation
+ * that is atomic with respect to all other filesystem activities that might
+ * affect the directory. The {@link #createDirectories createDirectories}
+ * method should be used where it is required to create all nonexistent
+ * parent directories first.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * file-attributes} to set atomically when creating the directory. Each
+ * attribute is identified by its {@link FileAttribute#name name}. If more
+ * than one attribute of the same name is included in the array then all but
+ * the last occurrence is ignored.
+ *
+ * @param dir
+ * the directory to create
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the directory
+ *
+ * @return the directory
+ *
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the directory
+ * @throws FileAlreadyExistsException
+ * if a directory could not otherwise be created because a file of
+ * that name already exists <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs or the parent directory does not exist
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the new directory.
+ */
+ public static Path createDirectory(Path dir, FileAttribute<?>... attrs)
+ throws IOException
+ {
+ provider(dir).createDirectory(dir, attrs);
+ return dir;
+ }
+
+ /**
+ * Creates a directory by creating all nonexistent parent directories first.
+ * Unlike the {@link #createDirectory createDirectory} method, an exception
+ * is not thrown if the directory could not be created because it already
+ * exists.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * file-attributes} to set atomically when creating the nonexistent
+ * directories. Each file attribute is identified by its {@link
+ * FileAttribute#name name}. If more than one attribute of the same name is
+ * included in the array then all but the last occurrence is ignored.
+ *
+ * <p> If this method fails, then it may do so after creating some, but not
+ * all, of the parent directories.
+ *
+ * @param dir
+ * the directory to create
+ *
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the directory
+ *
+ * @return the directory
+ *
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the directory
+ * @throws FileAlreadyExistsException
+ * if {@code dir} exists but is not a directory <i>(optional specific
+ * exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * in the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked prior to attempting to create a directory and
+ * its {@link SecurityManager#checkRead(String) checkRead} is
+ * invoked for each parent directory that is checked. If {@code
+ * dir} is not an absolute path then its {@link Path#toAbsolutePath
+ * toAbsolutePath} may need to be invoked to get its absolute path.
+ * This may invoke the security manager's {@link
+ * SecurityManager#checkPropertyAccess(String) checkPropertyAccess}
+ * method to check access to the system property {@code user.dir}
+ */
+ public static Path createDirectories(Path dir, FileAttribute<?>... attrs)
+ throws IOException
+ {
+ // attempt to create the directory
+ try {
+ createAndCheckIsDirectory(dir, attrs);
+ return dir;
+ } catch (FileAlreadyExistsException x) {
+ // file exists and is not a directory
+ throw x;
+ } catch (IOException x) {
+ // parent may not exist or other reason
+ }
+ SecurityException se = null;
+ try {
+ dir = dir.toAbsolutePath();
+ } catch (SecurityException x) {
+ // don't have permission to get absolute path
+ se = x;
+ }
+ // find a decendent that exists
+ Path parent = dir.getParent();
+ while (parent != null) {
+ try {
+ provider(parent).checkAccess(parent);
+ break;
+ } catch (NoSuchFileException x) {
+ // does not exist
+ }
+ parent = parent.getParent();
+ }
+ if (parent == null) {
+ // unable to find existing parent
+ if (se != null)
+ throw se;
+ throw new IOException("Root directory does not exist");
+ }
+
+ // create directories
+ Path child = parent;
+ for (Path name: parent.relativize(dir)) {
+ child = child.resolve(name);
+ createAndCheckIsDirectory(child, attrs);
+ }
+ return dir;
+ }
+
+ /**
+ * Used by createDirectories to attempt to create a directory. A no-op
+ * if the directory already exists.
+ */
+ private static void createAndCheckIsDirectory(Path dir,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ try {
+ createDirectory(dir, attrs);
+ } catch (FileAlreadyExistsException x) {
+ if (!isDirectory(dir, LinkOption.NOFOLLOW_LINKS))
+ throw x;
+ }
+ }
+
+ /**
+ * Creates a new empty file in the specified directory, using the given
+ * prefix and suffix strings to generate its name. The resulting
+ * {@code Path} is associated with the same {@code FileSystem} as the given
+ * directory.
+ *
+ * <p> The details as to how the name of the file is constructed is
+ * implementation dependent and therefore not specified. Where possible
+ * the {@code prefix} and {@code suffix} are used to construct candidate
+ * names in the same manner as the {@link
+ * java.io.File#createTempFile(String,String,File)} method.
+ *
+ * <p> As with the {@code File.createTempFile} methods, this method is only
+ * part of a temporary-file facility. Where used as a <em>work files</em>,
+ * the resulting file may be opened using the {@link
+ * StandardOpenOption#DELETE_ON_CLOSE DELETE_ON_CLOSE} option so that the
+ * file is deleted when the appropriate {@code close} method is invoked.
+ * Alternatively, a {@link Runtime#addShutdownHook shutdown-hook}, or the
+ * {@link java.io.File#deleteOnExit} mechanism may be used to delete the
+ * file automatically.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * file-attributes} to set atomically when creating the file. Each attribute
+ * is identified by its {@link FileAttribute#name name}. If more than one
+ * attribute of the same name is included in the array then all but the last
+ * occurrence is ignored. When no file attributes are specified, then the
+ * resulting file may have more restrictive access permissions to files
+ * created by the {@link java.io.File#createTempFile(String,String,File)}
+ * method.
+ *
+ * @param dir
+ * the path to directory in which to create the file
+ * @param prefix
+ * the prefix string to be used in generating the file's name;
+ * may be {@code null}
+ * @param suffix
+ * the suffix string to be used in generating the file's name;
+ * may be {@code null}, in which case "{@code .tmp}" is used
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the file
+ *
+ * @return the path to the newly created file that did not exist before
+ * this method was invoked
+ *
+ * @throws IllegalArgumentException
+ * if the prefix or suffix parameters cannot be used to generate
+ * a candidate file name
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the directory
+ * @throws IOException
+ * if an I/O error occurs or {@code dir} does not exist
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the file.
+ */
+ public static Path createTempFile(Path dir,
+ String prefix,
+ String suffix,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ return TempFileHelper.createTempFile(dir, prefix, suffix, attrs);
+ }
+
+ /**
+ * Creates an empty file in the default temporary-file directory, using
+ * the given prefix and suffix to generate its name. The resulting {@code
+ * Path} is associated with the default {@code FileSystem}.
+ *
+ * <p> This method works in exactly the manner specified by the
+ * {@link #createTempFile(Path,String,String,FileAttribute[])} method for
+ * the case that the {@code dir} parameter is the temporary-file directory.
+ *
+ * @param prefix
+ * the prefix string to be used in generating the file's name;
+ * may be {@code null}
+ * @param suffix
+ * the suffix string to be used in generating the file's name;
+ * may be {@code null}, in which case "{@code .tmp}" is used
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the file
+ *
+ * @return the path to the newly created file that did not exist before
+ * this method was invoked
+ *
+ * @throws IllegalArgumentException
+ * if the prefix or suffix parameters cannot be used to generate
+ * a candidate file name
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the directory
+ * @throws IOException
+ * if an I/O error occurs or the temporary-file directory does not
+ * exist
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the file.
+ */
+ public static Path createTempFile(String prefix,
+ String suffix,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ return TempFileHelper.createTempFile(null, prefix, suffix, attrs);
+ }
+
+ /**
+ * Creates a new directory in the specified directory, using the given
+ * prefix to generate its name. The resulting {@code Path} is associated
+ * with the same {@code FileSystem} as the given directory.
+ *
+ * <p> The details as to how the name of the directory is constructed is
+ * implementation dependent and therefore not specified. Where possible
+ * the {@code prefix} is used to construct candidate names.
+ *
+ * <p> As with the {@code createTempFile} methods, this method is only
+ * part of a temporary-file facility. A {@link Runtime#addShutdownHook
+ * shutdown-hook}, or the {@link java.io.File#deleteOnExit} mechanism may be
+ * used to delete the directory automatically.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * file-attributes} to set atomically when creating the directory. Each
+ * attribute is identified by its {@link FileAttribute#name name}. If more
+ * than one attribute of the same name is included in the array then all but
+ * the last occurrence is ignored.
+ *
+ * @param dir
+ * the path to directory in which to create the directory
+ * @param prefix
+ * the prefix string to be used in generating the directory's name;
+ * may be {@code null}
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the directory
+ *
+ * @return the path to the newly created directory that did not exist before
+ * this method was invoked
+ *
+ * @throws IllegalArgumentException
+ * if the prefix cannot be used to generate a candidate directory name
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the directory
+ * @throws IOException
+ * if an I/O error occurs or {@code dir} does not exist
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access when creating the
+ * directory.
+ */
+ public static Path createTempDirectory(Path dir,
+ String prefix,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ return TempFileHelper.createTempDirectory(dir, prefix, attrs);
+ }
+
+ /**
+ * Creates a new directory in the default temporary-file directory, using
+ * the given prefix and suffix to generate its name. The resulting {@code
+ * Path} is associated with the default {@code FileSystem}.
+ *
+ * <p> This method works in exactly the manner specified by {@link
+ * #createTempDirectory(Path,String,FileAttribute[])} method for the case
+ * that the {@code dir} parameter is the temporary-file directory.
+ *
+ * @param prefix
+ * the prefix string to be used in generating the directory's name;
+ * may be {@code null}
+ * @param attrs
+ * an optional list of file attributes to set atomically when
+ * creating the directory
+ *
+ * @return the path to the newly created directory that did not exist before
+ * this method was invoked
+ *
+ * @throws IllegalArgumentException
+ * if the prefix cannot be used to generate a candidate directory name
+ * @throws UnsupportedOperationException
+ * if the array contains an attribute that cannot be set atomically
+ * when creating the directory
+ * @throws IOException
+ * if an I/O error occurs or the temporary-file directory does not
+ * exist
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access when creating the
+ * directory.
+ */
+ public static Path createTempDirectory(String prefix,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ return TempFileHelper.createTempDirectory(null, prefix, attrs);
+ }
+
+ /**
+ * Creates a symbolic link to a target <i>(optional operation)</i>.
+ *
+ * <p> The {@code target} parameter is the target of the link. It may be an
+ * {@link Path#isAbsolute absolute} or relative path and may not exist. When
+ * the target is a relative path then file system operations on the resulting
+ * link are relative to the path of the link.
+ *
+ * <p> The {@code attrs} parameter is optional {@link FileAttribute
+ * attributes} to set atomically when creating the link. Each attribute is
+ * identified by its {@link FileAttribute#name name}. If more than one attribute
+ * of the same name is included in the array then all but the last occurrence
+ * is ignored.
+ *
+ * <p> Where symbolic links are supported, but the underlying {@link FileStore}
+ * does not support symbolic links, then this may fail with an {@link
+ * IOException}. Additionally, some operating systems may require that the
+ * Java virtual machine be started with implementation specific privileges to
+ * create symbolic links, in which case this method may throw {@code IOException}.
+ *
+ * @param link
+ * the path of the symbolic link to create
+ * @param target
+ * the target of the symbolic link
+ * @param attrs
+ * the array of attributes to set atomically when creating the
+ * symbolic link
+ *
+ * @return the path to the symbolic link
+ *
+ * @throws UnsupportedOperationException
+ * if the implementation does not support symbolic links or the
+ * array contains an attribute that cannot be set atomically when
+ * creating the symbolic link
+ * @throws FileAlreadyExistsException
+ * if a file with the name already exists <i>(optional specific
+ * exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager
+ * is installed, it denies {@link LinkPermission}<tt>("symbolic")</tt>
+ * or its {@link SecurityManager#checkWrite(String) checkWrite}
+ * method denies write access to the path of the symbolic link.
+ */
+ public static Path createSymbolicLink(Path link, Path target,
+ FileAttribute<?>... attrs)
+ throws IOException
+ {
+ provider(link).createSymbolicLink(link, target, attrs);
+ return link;
+ }
+
+ /**
+ * Creates a new link (directory entry) for an existing file <i>(optional
+ * operation)</i>.
+ *
+ * <p> The {@code link} parameter locates the directory entry to create.
+ * The {@code existing} parameter is the path to an existing file. This
+ * method creates a new directory entry for the file so that it can be
+ * accessed using {@code link} as the path. On some file systems this is
+ * known as creating a "hard link". Whether the file attributes are
+ * maintained for the file or for each directory entry is file system
+ * specific and therefore not specified. Typically, a file system requires
+ * that all links (directory entries) for a file be on the same file system.
+ * Furthermore, on some platforms, the Java virtual machine may require to
+ * be started with implementation specific privileges to create hard links
+ * or to create links to directories.
+ *
+ * @param link
+ * the link (directory entry) to create
+ * @param existing
+ * a path to an existing file
+ *
+ * @return the path to the link (directory entry)
+ *
+ * @throws UnsupportedOperationException
+ * if the implementation does not support adding an existing file
+ * to a directory
+ * @throws FileAlreadyExistsException
+ * if the entry could not otherwise be created because a file of
+ * that name already exists <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager
+ * is installed, it denies {@link LinkPermission}<tt>("hard")</tt>
+ * or its {@link SecurityManager#checkWrite(String) checkWrite}
+ * method denies write access to either the link or the
+ * existing file.
+ */
+ public static Path createLink(Path link, Path existing) throws IOException {
+ provider(link).createLink(link, existing);
+ return link;
+ }
+
+ /**
+ * Deletes a file.
+ *
+ * <p> An implementation may require to examine the file to determine if the
+ * file is a directory. Consequently this method may not be atomic with respect
+ * to other file system operations. If the file is a symbolic link then the
+ * symbolic link itself, not the final target of the link, is deleted.
+ *
+ * <p> If the file is a directory then the directory must be empty. In some
+ * implementations a directory has entries for special files or links that
+ * are created when the directory is created. In such implementations a
+ * directory is considered empty when only the special entries exist.
+ * This method can be used with the {@link #walkFileTree walkFileTree}
+ * method to delete a directory and all entries in the directory, or an
+ * entire <i>file-tree</i> where required.
+ *
+ * <p> On some operating systems it may not be possible to remove a file when
+ * it is open and in use by this Java virtual machine or other programs.
+ *
+ * @param path
+ * the path to the file to delete
+ *
+ * @throws NoSuchFileException
+ * if the file does not exist <i>(optional specific exception)</i>
+ * @throws DirectoryNotEmptyException
+ * if the file is a directory and could not otherwise be deleted
+ * because the directory is not empty <i>(optional specific
+ * exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkDelete(String)} method
+ * is invoked to check delete access to the file
+ */
+ public static void delete(Path path) throws IOException {
+ provider(path).delete(path);
+ }
+
+ /**
+ * Deletes a file if it exists.
+ *
+ * <p> As with the {@link #delete(Path) delete(Path)} method, an
+ * implementation may need to examine the file to determine if the file is a
+ * directory. Consequently this method may not be atomic with respect to
+ * other file system operations. If the file is a symbolic link, then the
+ * symbolic link itself, not the final target of the link, is deleted.
+ *
+ * <p> If the file is a directory then the directory must be empty. In some
+ * implementations a directory has entries for special files or links that
+ * are created when the directory is created. In such implementations a
+ * directory is considered empty when only the special entries exist.
+ *
+ * <p> On some operating systems it may not be possible to remove a file when
+ * it is open and in use by this Java virtual machine or other programs.
+ *
+ * @param path
+ * the path to the file to delete
+ *
+ * @return {@code true} if the file was deleted by this method; {@code
+ * false} if the file could not be deleted because it did not
+ * exist
+ *
+ * @throws DirectoryNotEmptyException
+ * if the file is a directory and could not otherwise be deleted
+ * because the directory is not empty <i>(optional specific
+ * exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkDelete(String)} method
+ * is invoked to check delete access to the file.
+ */
+ public static boolean deleteIfExists(Path path) throws IOException {
+ return provider(path).deleteIfExists(path);
+ }
+
+ // -- Copying and moving files --
+
+ /**
+ * Copy a file to a target file.
+ *
+ * <p> This method copies a file to the target file with the {@code
+ * options} parameter specifying how the copy is performed. By default, the
+ * copy fails if the target file already exists or is a symbolic link,
+ * except if the source and target are the {@link #isSameFile same} file, in
+ * which case the method completes without copying the file. File attributes
+ * are not required to be copied to the target file. If symbolic links are
+ * supported, and the file is a symbolic link, then the final target of the
+ * link is copied. If the file is a directory then it creates an empty
+ * directory in the target location (entries in the directory are not
+ * copied). This method can be used with the {@link #walkFileTree
+ * walkFileTree} method to copy a directory and all entries in the directory,
+ * or an entire <i>file-tree</i> where required.
+ *
+ * <p> The {@code options} parameter may include any of the following:
+ *
+ * <table border=1 cellpadding=5 summary="">
+ * <tr> <th>Option</th> <th>Description</th> </tr>
+ * <tr>
+ * <td> {@link StandardCopyOption#REPLACE_EXISTING REPLACE_EXISTING} </td>
+ * <td> If the target file exists, then the target file is replaced if it
+ * is not a non-empty directory. If the target file exists and is a
+ * symbolic link, then the symbolic link itself, not the target of
+ * the link, is replaced. </td>
+ * </tr>
+ * <tr>
+ * <td> {@link StandardCopyOption#COPY_ATTRIBUTES COPY_ATTRIBUTES} </td>
+ * <td> Attempts to copy the file attributes associated with this file to
+ * the target file. The exact file attributes that are copied is platform
+ * and file system dependent and therefore unspecified. Minimally, the
+ * {@link BasicFileAttributes#lastModifiedTime last-modified-time} is
+ * copied to the target file if supported by both the source and target
+ * file store. Copying of file timestamps may result in precision
+ * loss. </td>
+ * </tr>
+ * <tr>
+ * <td> {@link LinkOption#NOFOLLOW_LINKS NOFOLLOW_LINKS} </td>
+ * <td> Symbolic links are not followed. If the file is a symbolic link,
+ * then the symbolic link itself, not the target of the link, is copied.
+ * It is implementation specific if file attributes can be copied to the
+ * new link. In other words, the {@code COPY_ATTRIBUTES} option may be
+ * ignored when copying a symbolic link. </td>
+ * </tr>
+ * </table>
+ *
+ * <p> An implementation of this interface may support additional
+ * implementation specific options.
+ *
+ * <p> Copying a file is not an atomic operation. If an {@link IOException}
+ * is thrown then it possible that the target file is incomplete or some of
+ * its file attributes have not been copied from the source file. When the
+ * {@code REPLACE_EXISTING} option is specified and the target file exists,
+ * then the target file is replaced. The check for the existence of the file
+ * and the creation of the new file may not be atomic with respect to other
+ * file system activities.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want to copy a file into a directory, giving it the same file
+ * name as the source file:
+ * <pre>
+ * Path source = ...
+ * Path newdir = ...
+ * Files.copy(source, newdir.resolve(source.getFileName());
+ * </pre>
+ *
+ * @param source
+ * the path to the file to copy
+ * @param target
+ * the path to the target file
+ * @param options
+ * options specifying how the copy should be done
+ *
+ * @return the path to the target file
+ *
+ * @throws UnsupportedOperationException
+ * if the array contains a copy option that is not supported
+ * @throws FileAlreadyExistsException
+ * if the target file exists but cannot be replaced because the
+ * {@code REPLACE_EXISTING} option is not specified <i>(optional
+ * specific exception)</i>
+ * @throws DirectoryNotEmptyException
+ * the {@code REPLACE_EXISTING} option is specified but the file
+ * cannot be replaced because it is a non-empty directory
+ * <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the source file, the
+ * {@link SecurityManager#checkWrite(String) checkWrite} is invoked
+ * to check write access to the target file. If a symbolic link is
+ * copied the security manager is invoked to check {@link
+ * LinkPermission}{@code ("symbolic")}.
+ */
+ public static Path copy(Path source, Path target, CopyOption... options)
+ throws IOException
+ {
+ FileSystemProvider provider = provider(source);
+ if (provider(target) == provider) {
+ // same provider
+ provider.copy(source, target, options);
+ } else {
+ // different providers
+ CopyMoveHelper.copyToForeignTarget(source, target, options);
+ }
+ return target;
+ }
+
+ /**
+ * Move or rename a file to a target file.
+ *
+ * <p> By default, this method attempts to move the file to the target
+ * file, failing if the target file exists except if the source and
+ * target are the {@link #isSameFile same} file, in which case this method
+ * has no effect. If the file is a symbolic link then the symbolic link
+ * itself, not the target of the link, is moved. This method may be
+ * invoked to move an empty directory. In some implementations a directory
+ * has entries for special files or links that are created when the
+ * directory is created. In such implementations a directory is considered
+ * empty when only the special entries exist. When invoked to move a
+ * directory that is not empty then the directory is moved if it does not
+ * require moving the entries in the directory. For example, renaming a
+ * directory on the same {@link FileStore} will usually not require moving
+ * the entries in the directory. When moving a directory requires that its
+ * entries be moved then this method fails (by throwing an {@code
+ * IOException}). To move a <i>file tree</i> may involve copying rather
+ * than moving directories and this can be done using the {@link
+ * #copy copy} method in conjunction with the {@link
+ * #walkFileTree Files.walkFileTree} utility method.
+ *
+ * <p> The {@code options} parameter may include any of the following:
+ *
+ * <table border=1 cellpadding=5 summary="">
+ * <tr> <th>Option</th> <th>Description</th> </tr>
+ * <tr>
+ * <td> {@link StandardCopyOption#REPLACE_EXISTING REPLACE_EXISTING} </td>
+ * <td> If the target file exists, then the target file is replaced if it
+ * is not a non-empty directory. If the target file exists and is a
+ * symbolic link, then the symbolic link itself, not the target of
+ * the link, is replaced. </td>
+ * </tr>
+ * <tr>
+ * <td> {@link StandardCopyOption#ATOMIC_MOVE ATOMIC_MOVE} </td>
+ * <td> The move is performed as an atomic file system operation and all
+ * other options are ignored. If the target file exists then it is
+ * implementation specific if the existing file is replaced or this method
+ * fails by throwing an {@link IOException}. If the move cannot be
+ * performed as an atomic file system operation then {@link
+ * AtomicMoveNotSupportedException} is thrown. This can arise, for
+ * example, when the target location is on a different {@code FileStore}
+ * and would require that the file be copied, or target location is
+ * associated with a different provider to this object. </td>
+ * </table>
+ *
+ * <p> An implementation of this interface may support additional
+ * implementation specific options.
+ *
+ * <p> Where the move requires that the file be copied then the {@link
+ * BasicFileAttributes#lastModifiedTime last-modified-time} is copied to the
+ * new file. An implementation may also attempt to copy other file
+ * attributes but is not required to fail if the file attributes cannot be
+ * copied. When the move is performed as a non-atomic operation, and a {@code
+ * IOException} is thrown, then the state of the files is not defined. The
+ * original file and the target file may both exist, the target file may be
+ * incomplete or some of its file attributes may not been copied from the
+ * original file.
+ *
+ * <p> <b>Usage Examples:</b>
+ * Suppose we want to rename a file to "newname", keeping the file in the
+ * same directory:
+ * <pre>
+ * Path source = ...
+ * Files.move(source, source.resolveSibling("newname"));
+ * </pre>
+ * Alternatively, suppose we want to move a file to new directory, keeping
+ * the same file name, and replacing any existing file of that name in the
+ * directory:
+ * <pre>
+ * Path source = ...
+ * Path newdir = ...
+ * Files.move(source, newdir.resolve(source.getFileName()), REPLACE_EXISTING);
+ * </pre>
+ *
+ * @param source
+ * the path to the file to move
+ * @param target
+ * the path to the target file
+ * @param options
+ * options specifying how the move should be done
+ *
+ * @return the path to the target file
+ *
+ * @throws UnsupportedOperationException
+ * if the array contains a copy option that is not supported
+ * @throws FileAlreadyExistsException
+ * if the target file exists but cannot be replaced because the
+ * {@code REPLACE_EXISTING} option is not specified <i>(optional
+ * specific exception)</i>
+ * @throws DirectoryNotEmptyException
+ * the {@code REPLACE_EXISTING} option is specified but the file
+ * cannot be replaced because it is a non-empty directory
+ * <i>(optional specific exception)</i>
+ * @throws AtomicMoveNotSupportedException
+ * if the options array contains the {@code ATOMIC_MOVE} option but
+ * the file cannot be moved as an atomic file system operation.
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to both the source and
+ * target file.
+ */
+ public static Path move(Path source, Path target, CopyOption... options)
+ throws IOException
+ {
+ FileSystemProvider provider = provider(source);
+ if (provider(target) == provider) {
+ // same provider
+ provider.move(source, target, options);
+ } else {
+ // different providers
+ CopyMoveHelper.moveToForeignTarget(source, target, options);
+ }
+ return target;
+ }
+
+ // -- Miscellenous --
+
+ /**
+ * Reads the target of a symbolic link <i>(optional operation)</i>.
+ *
+ * <p> If the file system supports <a href="package-summary.html#links">symbolic
+ * links</a> then this method is used to read the target of the link, failing
+ * if the file is not a symbolic link. The target of the link need not exist.
+ * The returned {@code Path} object will be associated with the same file
+ * system as {@code link}.
+ *
+ * @param link
+ * the path to the symbolic link
+ *
+ * @return a {@code Path} object representing the target of the link
+ *
+ * @throws UnsupportedOperationException
+ * if the implementation does not support symbolic links
+ * @throws NotLinkException
+ * if the target could otherwise not be read because the file
+ * is not a symbolic link <i>(optional specific exception)</i>
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager
+ * is installed, it checks that {@code FilePermission} has been
+ * granted with the "{@code readlink}" action to read the link.
+ */
+ public static Path readSymbolicLink(Path link) throws IOException {
+ return provider(link).readSymbolicLink(link);
+ }
+
+ /**
+ * Returns the {@link FileStore} representing the file store where a file
+ * is located.
+ *
+ * <p> Once a reference to the {@code FileStore} is obtained it is
+ * implementation specific if operations on the returned {@code FileStore},
+ * or {@link FileStoreAttributeView} objects obtained from it, continue
+ * to depend on the existence of the file. In particular the behavior is not
+ * defined for the case that the file is deleted or moved to a different
+ * file store.
+ *
+ * @param path
+ * the path to the file
+ *
+ * @return the file store where the file is stored
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file, and in
+ * addition it checks {@link RuntimePermission}<tt>
+ * ("getFileStoreAttributes")</tt>
+ */
+ public static FileStore getFileStore(Path path) throws IOException {
+ return provider(path).getFileStore(path);
+ }
+
+ /**
+ * Tests if two paths locate the same file.
+ *
+ * <p> If both {@code Path} objects are {@link Path#equals(Object) equal}
+ * then this method returns {@code true} without checking if the file exists.
+ * If the two {@code Path} objects are associated with different providers
+ * then this method returns {@code false}. Otherwise, this method checks if
+ * both {@code Path} objects locate the same file, and depending on the
+ * implementation, may require to open or access both files.
+ *
+ * <p> If the file system and files remain static, then this method implements
+ * an equivalence relation for non-null {@code Paths}.
+ * <ul>
+ * <li>It is <i>reflexive</i>: for {@code Path} {@code f},
+ * {@code isSameFile(f,f)} should return {@code true}.
+ * <li>It is <i>symmetric</i>: for two {@code Paths} {@code f} and {@code g},
+ * {@code isSameFile(f,g)} will equal {@code isSameFile(g,f)}.
+ * <li>It is <i>transitive</i>: for three {@code Paths}
+ * {@code f}, {@code g}, and {@code h}, if {@code isSameFile(f,g)} returns
+ * {@code true} and {@code isSameFile(g,h)} returns {@code true}, then
+ * {@code isSameFile(g,h)} will return return {@code true}.
+ * </ul>
+ *
+ * @param path
+ * one path to the file
+ * @param path2
+ * the other path
+ *
+ * @return {@code true} if, and only if, the two paths locate the same file
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to both files.
+ *
+ * @see java.nio.file.attribute.BasicFileAttributes#fileKey
+ */
+ public static boolean isSameFile(Path path, Path path2) throws IOException {
+ return provider(path).isSameFile(path, path2);
+ }
+
+ /**
+ * Tells whether or not a file is considered <em>hidden</em>. The exact
+ * definition of hidden is platform or provider dependent. On UNIX for
+ * example a file is considered to be hidden if its name begins with a
+ * period character ('.'). On Windows a file is considered hidden if it
+ * isn't a directory and the DOS {@link DosFileAttributes#isHidden hidden}
+ * attribute is set.
+ *
+ * <p> Depending on the implementation this method may require to access
+ * the file system to determine if the file is considered hidden.
+ *
+ * @param path
+ * the path to the file to test
+ *
+ * @return {@code true} if the file is considered hidden
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file.
+ */
+ public static boolean isHidden(Path path) throws IOException {
+ return provider(path).isHidden(path);
+ }
+
// lazy loading of default and installed file type detectors
- private static class DefaultFileTypeDetectorHolder {
+ private static class FileTypeDetectors{
static final FileTypeDetector defaultFileTypeDetector =
sun.nio.fs.DefaultFileTypeDetector.create();
static final List<FileTypeDetector> installeDetectors =
loadInstalledDetectors();
@@ -52,11 +1476,11 @@
// loads all installed file type detectors
private static List<FileTypeDetector> loadInstalledDetectors() {
return AccessController
.doPrivileged(new PrivilegedAction<List<FileTypeDetector>>() {
@Override public List<FileTypeDetector> run() {
- List<FileTypeDetector> list = new ArrayList<FileTypeDetector>();
+ List<FileTypeDetector> list = new ArrayList<>();
ServiceLoader<FileTypeDetector> loader = ServiceLoader
.load(FileTypeDetector.class, ClassLoader.getSystemClassLoader());
for (FileTypeDetector detector: loader) {
list.add(detector);
}
@@ -98,38 +1522,952 @@
* defined by <a href="http://www.ietf.org/rfc/rfc2045.txt"><i>RFC 2045:
* Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet
* Message Bodies</i></a>. The string is guaranteed to be parsable according
* to the grammar in the RFC.
*
- * @param file
- * The file reference
+ * @param path
+ * the path to the file to probe
*
* @return The content type of the file, or {@code null} if the content
* type cannot be determined
*
* @throws IOException
- * If an I/O error occurs
+ * if an I/O error occurs
* @throws SecurityException
* If a security manager is installed and it denies an unspecified
* permission required by a file type detector implementation.
*/
- public static String probeContentType(FileRef file)
+ public static String probeContentType(Path path)
throws IOException
{
// try installed file type detectors
- for (FileTypeDetector detector: DefaultFileTypeDetectorHolder.installeDetectors) {
- String result = detector.probeContentType(file);
+ for (FileTypeDetector detector: FileTypeDetectors.installeDetectors) {
+ String result = detector.probeContentType(path);
if (result != null)
return result;
}
// fallback to default
- return DefaultFileTypeDetectorHolder.defaultFileTypeDetector
- .probeContentType(file);
+ return FileTypeDetectors.defaultFileTypeDetector.probeContentType(path);
}
+ // -- File Attributes --
+
/**
+ * Returns a file attribute view of a given type.
+ *
+ * <p> A file attribute view provides a read-only or updatable view of a
+ * set of file attributes. This method is intended to be used where the file
+ * attribute view defines type-safe methods to read or update the file
+ * attributes. The {@code type} parameter is the type of the attribute view
+ * required and the method returns an instance of that type if supported.
+ * The {@link BasicFileAttributeView} type supports access to the basic
+ * attributes of a file. Invoking this method to select a file attribute
+ * view of that type will always return an instance of that class.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled by the resulting file attribute view for the case that the
+ * file is a symbolic link. By default, symbolic links are followed. If the
+ * option {@link LinkOption#NOFOLLOW_LINKS NOFOLLOW_LINKS} is present then
+ * symbolic links are not followed. This option is ignored by implementations
+ * that do not support symbolic links.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want read or set a file's ACL, if supported:
+ * <pre>
+ * Path path = ...
+ * AclFileAttributeView view = Files.getFileAttributeView(path, AclFileAttributeView.class);
+ * if (view != null) {
+ * List<AclEntry> acl = view.getAcl();
+ * :
+ * }
+ * </pre>
+ *
+ *
+ * @param path
+ * the path to the file
+ * @param type
+ * the {@code Class} object corresponding to the file attribute view
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return a file attribute view of the specified type, or {@code null} if
+ * the attribute view type is not available
+ */
+ public static <V extends FileAttributeView> V getFileAttributeView(Path path,
+ Class<V> type,
+ LinkOption... options)
+ {
+ return provider(path).getFileAttributeView(path, type, options);
+ }
+
+ /**
+ * Reads a file's attributes as a bulk operation.
+ *
+ * <p> The {@code type} parameter is the type of the attributes required
+ * and this method returns an instance of that type if supported. All
+ * implementations support a basic set of file attributes and so invoking
+ * this method with a {@code type} parameter of {@code
+ * BasicFileAttributes.class} will not throw {@code
+ * UnsupportedOperationException}.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> It is implementation specific if all file attributes are read as an
+ * atomic operation with respect to other file system operations.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want to read a file's attributes in bulk:
+ * <pre>
+ * Path path = ...
+ * BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
+ * </pre>
+ * Alternatively, suppose we want to read file's POSIX attributes without
+ * following symbolic links:
+ * <pre>
+ * PosixFileAttributes attrs = Files.readAttributes(path, PosixFileAttributes.class, NOFOLLOW_LINKS);
+ * </pre>
+ *
+ * @param path
+ * the path to the file
+ * @param type
+ * the {@code Class} of the file attributes required
+ * to read
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return the file attributes
+ *
+ * @throws UnsupportedOperationException
+ * if an attributes of the given type are not supported
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file. If this
+ * method is invoked to read security sensitive attributes then the
+ * security manager may be invoke to check for additional permissions.
+ */
+ public static <A extends BasicFileAttributes> A readAttributes(Path path,
+ Class<A> type,
+ LinkOption... options)
+ throws IOException
+ {
+ return provider(path).readAttributes(path, type, options);
+ }
+
+ /**
+ * Sets the value of a file attribute.
+ *
+ * <p> The {@code attribute} parameter identifies the attribute to be set
+ * and takes the form:
+ * <blockquote>
+ * [<i>view-name</i><b>:</b>]<i>attribute-name</i>
+ * </blockquote>
+ * where square brackets [...] delineate an optional component and the
+ * character {@code ':'} stands for itself.
+ *
+ * <p> <i>view-name</i> is the {@link FileAttributeView#name name} of a {@link
+ * FileAttributeView} that identifies a set of file attributes. If not
+ * specified then it defaults to {@code "basic"}, the name of the file
+ * attribute view that identifies the basic set of file attributes common to
+ * many file systems. <i>attribute-name</i> is the name of the attribute
+ * within the set.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is set. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want to set the DOS "hidden" attribute:
+ * <pre>
+ * Path path = ...
+ * Files.setAttribute(path, "dos:hidden", true);
+ * </pre>
+ *
+ * @param path
+ * the path to the file
+ * @param attribute
+ * the attribute to set
+ * @param value
+ * the attribute value
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return the {@code path} parameter
+ *
+ * @throws UnsupportedOperationException
+ * if the attribute view is not available or it does not support
+ * updating the attribute
+ * @throws IllegalArgumentException
+ * if the attribute value is of the correct type but has an
+ * inappropriate value
+ * @throws ClassCastException
+ * if the attribute value is not of the expected type or is a
+ * collection containing elements that are not of the expected
+ * type
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkWrite(String) checkWrite}
+ * method denies write access to the file. If this method is invoked
+ * to set security sensitive attributes then the security manager
+ * may be invoked to check for additional permissions.
+ */
+ public static Path setAttribute(Path path, String attribute, Object value,
+ LinkOption... options)
+ throws IOException
+ {
+ provider(path).setAttribute(path, attribute, value, options);
+ return path;
+ }
+
+ /**
+ * Reads the value of a file attribute.
+ *
+ * <p> The {@code attribute} parameter identifies the attribute to be read
+ * and takes the form:
+ * <blockquote>
+ * [<i>view-name</i><b>:</b>]<i>attribute-name</i>
+ * </blockquote>
+ * where square brackets [...] delineate an optional component and the
+ * character {@code ':'} stands for itself.
+ *
+ * <p> <i>view-name</i> is the {@link FileAttributeView#name name} of a {@link
+ * FileAttributeView} that identifies a set of file attributes. If not
+ * specified then it defaults to {@code "basic"}, the name of the file
+ * attribute view that identifies the basic set of file attributes common to
+ * many file systems. <i>attribute-name</i> is the name of the attribute.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we require the user ID of the file owner on a system that
+ * supports a "{@code unix}" view:
+ * <pre>
+ * Path path = ...
+ * int uid = (Integer)Files.getAttribute(path, "unix:uid");
+ * </pre>
+ *
+ * @param path
+ * the path to the file
+ * @param attribute
+ * the attribute to read
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return the attribute value or {@code null} if the attribute view
+ * is not available or it does not support reading the attribute
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file. If this method is invoked
+ * to read security sensitive attributes then the security manager
+ * may be invoked to check for additional permissions.
+ */
+ public static Object getAttribute(Path path, String attribute,
+ LinkOption... options)
+ throws IOException
+ {
+ // only one attribute should be read
+ if (attribute.indexOf('*') >= 0 || attribute.indexOf(',') >= 0)
+ return null;
+ Map<String,Object> map = readAttributes(path, attribute, options);
+ String name;
+ int pos = attribute.indexOf(':');
+ if (pos == -1) {
+ name = attribute;
+ } else {
+ name = (pos == attribute.length()) ? "" : attribute.substring(pos+1);
+ }
+ return map.get(name);
+ }
+
+ /**
+ * Reads a set of file attributes as a bulk operation.
+ *
+ * <p> The {@code attributes} parameter identifies the attributes to be read
+ * and takes the form:
+ * <blockquote>
+ * [<i>view-name</i><b>:</b>]<i>attribute-list</i>
+ * </blockquote>
+ * where square brackets [...] delineate an optional component and the
+ * character {@code ':'} stands for itself.
+ *
+ * <p> <i>view-name</i> is the {@link FileAttributeView#name name} of a {@link
+ * FileAttributeView} that identifies a set of file attributes. If not
+ * specified then it defaults to {@code "basic"}, the name of the file
+ * attribute view that identifies the basic set of file attributes common to
+ * many file systems.
+ *
+ * <p> The <i>attribute-list</i> component is a comma separated list of
+ * zero or more names of attributes to read. If the list contains the value
+ * {@code "*"} then all attributes are read. Attributes that are not supported
+ * are ignored and will not be present in the returned map. It is
+ * implementation specific if all attributes are read as an atomic operation
+ * with respect to other file system operations.
+ *
+ * <p> The following examples demonstrate possible values for the {@code
+ * attributes} parameter:
+ *
+ * <blockquote>
+ * <table border="0">
+ * <tr>
+ * <td> {@code "*"} </td>
+ * <td> Read all {@link BasicFileAttributes basic-file-attributes}. </td>
+ * </tr>
+ * <tr>
+ * <td> {@code "size,lastModifiedTime,lastAccessTime"} </td>
+ * <td> Reads the file size, last modified time, and last access time
+ * attributes. </td>
+ * </tr>
+ * <tr>
+ * <td> {@code "posix:*"} </td>
+ * <td> Read all {@link PosixFileAttributes POSIX-file-attributes}. </td>
+ * </tr>
+ * <tr>
+ * <td> {@code "posix:permissions,owner,size"} </td>
+ * <td> Reads the POSX file permissions, owner, and file size. </td>
+ * </tr>
+ * </table>
+ * </blockquote>
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * @param path
+ * the path to the file
+ * @param attributes
+ * the attributes to read
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return a map of the attributes returned; may be empty. The map's keys
+ * are the attribute names, its values are the attribute values
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file. If this method is invoked
+ * to read security sensitive attributes then the security manager
+ * may be invoke to check for additional permissions.
+ */
+ public static Map<String,Object> readAttributes(Path path, String attributes,
+ LinkOption... options)
+ throws IOException
+ {
+ return provider(path).readAttributes(path, attributes, options);
+ }
+
+ /**
+ * Returns a file's POSIX file permissions.
+ *
+ * <p> The {@code path} parameter is associated with a {@code FileSystem}
+ * that supports the {@link PosixFileAttributeView}. This attribute view
+ * provides access to file attributes commonly associated with files on file
+ * systems used by operating systems that implement the Portable Operating
+ * System Interface (POSIX) family of standards.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * @param path
+ * the path to the file
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return the file permissions
+ *
+ * @throws UnsupportedOperationException
+ * if the associated file system does not support the {@code
+ * PosixFileAttributeView}
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, a security manager is
+ * installed, and it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>
+ * or its {@link SecurityManager#checkRead(String) checkRead} method
+ * denies read access to the file.
+ */
+ public static Set<PosixFilePermission> getPosixFilePermissions(Path path,
+ LinkOption... options)
+ throws IOException
+ {
+ return readAttributes(path, PosixFileAttributes.class, options).permissions();
+ }
+
+ /**
+ * Sets a file's POSIX permissions.
+ *
+ * <p> The {@code path} parameter is associated with a {@code FileSystem}
+ * that supports the {@link PosixFileAttributeView}. This attribute view
+ * provides access to file attributes commonly associated with files on file
+ * systems used by operating systems that implement the Portable Operating
+ * System Interface (POSIX) family of standards.
+ *
+ * @param path
+ * A file reference that locates the file
+ * @param perms
+ * The new set of permissions
+ *
+ * @throws UnsupportedOperationException
+ * if the associated file system does not support the {@code
+ * PosixFileAttributeView}
+ * @throws ClassCastException
+ * if the sets contains elements that are not of type {@code
+ * PosixFilePermission}
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>
+ * or its {@link SecurityManager#checkWrite(String) checkWrite}
+ * method denies write access to the file.
+ */
+ public static Path setPosixFilePermissions(Path path,
+ Set<PosixFilePermission> perms)
+ throws IOException
+ {
+ PosixFileAttributeView view =
+ getFileAttributeView(path, PosixFileAttributeView.class);
+ if (view == null)
+ throw new UnsupportedOperationException();
+ view.setPermissions(perms);
+ return path;
+ }
+
+ /**
+ * Returns the owner of a file.
+ *
+ * <p> The {@code path} parameter is associated with a file system that
+ * supports {@link FileOwnerAttributeView}. This file attribute view provides
+ * access to a file attribute that is the owner of the file.
+ *
+ * @param path
+ * A file reference that locates the file
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return A user principal representing the owner of the file
+ *
+ * @throws UnsupportedOperationException
+ * if the associated file system does not support the {@code
+ * FileOwnerAttributeView}
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>
+ * or its {@link SecurityManager#checkRead(String) checkRead} method
+ * denies read access to the file.
+ */
+ public static UserPrincipal getOwner(Path path, LinkOption... options) throws IOException {
+ FileOwnerAttributeView view =
+ getFileAttributeView(path, FileOwnerAttributeView.class, options);
+ if (view == null)
+ throw new UnsupportedOperationException();
+ return view.getOwner();
+ }
+
+ /**
+ * Updates the file owner.
+ *
+ * <p> The {@code path} parameter is associated with a file system that
+ * supports {@link FileOwnerAttributeView}. This file attribute view provides
+ * access to a file attribute that is the owner of the file.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want to make "joe" the owner of a file:
+ * <pre>
+ * Path path = ...
+ * UserPrincipalLookupService lookupService =
+ * provider(path).getUserPrincipalLookupService();
+ * UserPrincipal joe = lookupService.lookupPrincipalByName("joe");
+ * Files.setOwner(path, joe);
+ * </pre>
+ *
+ * @param path
+ * A file reference that locates the file
+ * @param owner
+ * The new file owner
+ *
+ * @throws UnsupportedOperationException
+ * if the associated file system does not support the {@code
+ * FileOwnerAttributeView}
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>
+ * or its {@link SecurityManager#checkWrite(String) checkWrite}
+ * method denies write access to the file.
+ *
+ * @see FileSystem#getUserPrincipalLookupService
+ * @see java.nio.file.attribute.UserPrincipalLookupService
+ */
+ public static Path setOwner(Path path, UserPrincipal owner)
+ throws IOException
+ {
+ FileOwnerAttributeView view =
+ getFileAttributeView(path, FileOwnerAttributeView.class);
+ if (view == null)
+ throw new UnsupportedOperationException();
+ view.setOwner(owner);
+ return path;
+ }
+
+ /**
+ * Tests whether a file is a symbolic link.
+ *
+ * <p> Where is it required to distinguish an I/O exception from the case
+ * that the file is not a symbolic link then the file attributes can be
+ * read with the {@link #readAttributes(Path,Class,LinkOption[])
+ * readAttributes} method and the file type tested with the {@link
+ * BasicFileAttributes#isSymbolicLink} method.
+ *
+ * @return {@code true} if the file is a symbolic link; {@code false} if
+ * the file does not exist, is not a symbolic link, or it cannot
+ * be determined if the file is symbolic link or not.
+ *
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file.
+ */
+ public static boolean isSymbolicLink(Path path) {
+ try {
+ return readAttributes(path,
+ BasicFileAttributes.class,
+ LinkOption.NOFOLLOW_LINKS).isSymbolicLink();
+ } catch (IOException ioe) {
+ return false;
+ }
+ }
+
+ /**
+ * Tests whether a file is a directory.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> Where is it required to distinguish an I/O exception from the case
+ * that the file is not a directory then the file attributes can be
+ * read with the {@link #readAttributes(Path,Class,LinkOption[])
+ * readAttributes} method and the file type tested with the {@link
+ * BasicFileAttributes#isDirectory} method.
+ *
+ * @param path
+ * the path to the file to test
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return {@code true} if the file is a directory; {@code false} if
+ * the file does not exist, is not a directory, or it cannot
+ * be determined if the file is directory or not.
+ *
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file.
+ */
+ public static boolean isDirectory(Path path, LinkOption... options) {
+ try {
+ return readAttributes(path, BasicFileAttributes.class, options).isDirectory();
+ } catch (IOException ioe) {
+ return false;
+ }
+ }
+
+ /**
+ * Tests whether a file is a regular file with opaque content.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> Where is it required to distinguish an I/O exception from the case
+ * that the file is not a regular file then the file attributes can be
+ * read with the {@link #readAttributes(Path,Class,LinkOption[])
+ * readAttributes} method and the file type tested with the {@link
+ * BasicFileAttributes#isRegularFile} method.
+ *
+ * @param path
+ * the path to the file
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return {@code true} if the file is a regular file; {@code false} if
+ * the file does not exist, is not a direcregular filetory, or it
+ * cannot be determined if the file is regular file or not.
+ *
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file.
+ */
+ public static boolean isRegularFile(Path path, LinkOption... options) {
+ try {
+ return readAttributes(path, BasicFileAttributes.class, options).isRegularFile();
+ } catch (IOException ioe) {
+ return false;
+ }
+ }
+
+ /**
+ * Returns a file's last modified time.
+ *
+ * <p> The {@code options} array may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed and the file attribute of the final target
+ * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * @param path
+ * the path to the file
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return a {@code FileTime} representing the time the file was last
+ * modified, or an implementation specific default when a time
+ * stamp to indicate the time of last modification is not supported
+ * by the file system
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file.
+ *
+ * @see BasicFileAttributes#lastModifiedTime
+ */
+ public static FileTime getLastModifiedTime(Path path, LinkOption... options)
+ throws IOException
+ {
+ return readAttributes(path, BasicFileAttributes.class, options).lastModifiedTime();
+ }
+
+ /**
+ * Updates a file's last modified time attribute. The file time is converted
+ * to the epoch and precision supported by the file system. Converting from
+ * finer to coarser granularities result in precision loss. The behavior of
+ * this method when attempting to set a timestamp to a value that is outside
+ * the range supported by the underlying file store is not defined. It may
+ * or not fail by throwing an {@code IOException}.
+ *
+ * <p> <b>Usage Example:</b>
+ * Suppose we want to set the last modified time to the current time:
+ * <pre>
+ * Path path = ...
+ * FileTime now = FileTime.fromMillis(System.currentTimeMillis());
+ * Files.setLastModifiedTime(path, now);
+ * </pre>
+ *
+ * @param path
+ * the path to the file
+ * @param time
+ * the new last modified time
+ *
+ * @return the file
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, the security manager's {@link
+ * SecurityManager#checkWrite(String) checkWrite} method is invoked
+ * to check write access to file
+ *
+ * @see BasicFileAttributeView#setTimes
+ */
+ public static Path setLastModifiedTime(Path path, FileTime time)
+ throws IOException
+ {
+ getFileAttributeView(path, BasicFileAttributeView.class)
+ .setTimes(time, null, null);
+ return path;
+ }
+
+ /**
+ * Returns the size of a file (in bytes). The size may differ from the
+ * actual size on the file system due to compression, support for sparse
+ * files, or other reasons. The size of files that are not {@link
+ * #isRegularFile regular} files is implementation specific and
+ * therefore unspecified.
+ *
+ * @param path
+ * the path to the file
+ *
+ * @return the file size, in bytes
+ *
+ * @throws IOException
+ * if an I/O error occurs
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, its {@link SecurityManager#checkRead(String) checkRead}
+ * method denies read access to the file.
+ *
+ * @see BasicFileAttributes#size
+ */
+ public static long size(Path path) throws IOException {
+ return readAttributes(path, BasicFileAttributes.class).size();
+ }
+
+ // -- Accessibility --
+
+ /**
+ * Returns {@code false} if NOFOLLOW_LINKS is present.
+ */
+ private static boolean followLinks(LinkOption... options) {
+ boolean followLinks = true;
+ for (LinkOption opt: options) {
+ if (opt == LinkOption.NOFOLLOW_LINKS) {
+ followLinks = false;
+ continue;
+ }
+ if (opt == null)
+ throw new NullPointerException();
+ throw new AssertionError("Should not get here");
+ }
+ return followLinks;
+ }
+
+ /**
+ * Tests whether a file exists.
+ *
+ * <p> The {@code options} parameter may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> Note that the result of this method is immediately outdated. If this
+ * method indicates the file exists then there is no guarantee that a
+ * subsequence access will succeed. Care should be taken when using this
+ * method in security sensitive applications.
+ *
+ * @param path
+ * the path to the file to test
+ * @param options
+ * options indicating how symbolic links are handled
+ * .
+ * @return {@code true} if the file exists; {@code false} if the file does
+ * not exist or its existence cannot be determined.
+ *
+ * @throws SecurityException
+ * In the case of the default provider, the {@link
+ * SecurityManager#checkRead(String)} is invoked to check
+ * read access to the file.
+ *
+ * @see #notExists
+ */
+ public static boolean exists(Path path, LinkOption... options) {
+ try {
+ if (followLinks(options)) {
+ provider(path).checkAccess(path);
+ } else {
+ // attempt to read attributes without following links
+ readAttributes(path, BasicFileAttributes.class,
+ LinkOption.NOFOLLOW_LINKS);
+ }
+ // file exists
+ return true;
+ } catch (IOException x) {
+ // does not exist or unable to determine if file exists
+ return false;
+ }
+
+ }
+
+ /**
+ * Tests whether the file located by this path does not exist. This method
+ * is intended for cases where it is required to take action when it can be
+ * confirmed that a file does not exist.
+ *
+ * <p> The {@code options} parameter may be used to indicate how symbolic links
+ * are handled for the case that the file is a symbolic link. By default,
+ * symbolic links are followed. If the option {@link LinkOption#NOFOLLOW_LINKS
+ * NOFOLLOW_LINKS} is present then symbolic links are not followed.
+ *
+ * <p> Note that this method is not the complement of the {@link #exists
+ * exists} method. Where it is not possible to determine if a file exists
+ * or not then both methods return {@code false}. As with the {@code exists}
+ * method, the result of this method is immediately outdated. If this
+ * method indicates the file does exist then there is no guarantee that a
+ * subsequence attempt to create the file will succeed. Care should be taken
+ * when using this method in security sensitive applications.
+ *
+ * @param path
+ * the path to the file to test
+ * @param options
+ * options indicating how symbolic links are handled
+ *
+ * @return {@code true} if the file does not exist; {@code false} if the
+ * file exists or its existence cannot be determined
+ *
+ * @throws SecurityException
+ * In the case of the default provider, the {@link
+ * SecurityManager#checkRead(String)} is invoked to check
+ * read access to the file.
+ */
+ public static boolean notExists(Path path, LinkOption... options) {
+ try {
+ if (followLinks(options)) {
+ provider(path).checkAccess(path);
+ } else {
+ // attempt to read attributes without following links
+ readAttributes(path, BasicFileAttributes.class,
+ LinkOption.NOFOLLOW_LINKS);
+ }
+ // file exists
+ return false;
+ } catch (NoSuchFileException x) {
+ // file confirmed not to exist
+ return true;
+ } catch (IOException x) {
+ return false;
+ }
+ }
+
+ /**
+ * Used by isReadbale, isWritable, isExecutable to test access to a file.
+ */
+ private static boolean isAccessible(Path path, AccessMode... modes) {
+ try {
+ provider(path).checkAccess(path, modes);
+ return true;
+ } catch (IOException x) {
+ return false;
+ }
+ }
+
+ /**
+ * Tests whether a file is readable. This method checks that a file exists
+ * and that this Java virtual machine has appropriate privileges that would
+ * allow it open the file for reading. Depending on the implementation, this
+ * method may require to read file permissions, access control lists, or
+ * other file attributes in order to check the effective access to the file.
+ * Consequently, this method may not be atomic with respect to other file
+ * system operations.
+ *
+ * <p> Note that the result of this method is immediately outdated, there is
+ * no guarantee that a subsequent attempt to open the file for reading will
+ * succeed (or even that it will access the same file). Care should be taken
+ * when using this method in security sensitive applications.
+ *
+ * @param path
+ * the path to the file to check
+ *
+ * @return {@code true} if the file exists and is readable; {@code false}
+ * if the file does not exist, read access would be denied because
+ * the Java virtual machine has insufficient privileges, or access
+ * cannot be determined
+ *
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * is invoked to check read access to the file.
+ */
+ public static boolean isReadable(Path path) {
+ return isAccessible(path, AccessMode.READ);
+ }
+
+ /**
+ * Tests whether a file is writable. This method checks that a file exists
+ * and that this Java virtual machine has appropriate privileges that would
+ * allow it open the file for writing. Depending on the implementation, this
+ * method may require to read file permissions, access control lists, or
+ * other file attributes in order to check the effective access to the file.
+ * Consequently, this method may not be atomic with respect to other file
+ * system operations.
+ *
+ * <p> Note that result of this method is immediately outdated, there is no
+ * guarantee that a subsequent attempt to open the file for writing will
+ * succeed (or even that it will access the same file). Care should be taken
+ * when using this method in security sensitive applications.
+ *
+ * @param path
+ * the path to the file to check
+ *
+ * @return {@code true} if the file exists and is writable; {@code false}
+ * if the file does not exist, write access would be denied because
+ * the Java virtual machine has insufficient privileges, or access
+ * cannot be determined
+ *
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * is invoked to check write access to the file.
+ */
+ public static boolean isWritable(Path path) {
+ return isAccessible(path, AccessMode.WRITE);
+ }
+
+ /**
+ * Tests whether a file is executable. This method checks that a file exists
+ * and that this Java virtual machine has appropriate privileges to {@link
+ * Runtime#exec execute} the file. The semantics may differ when checking
+ * access to a directory. For example, on UNIX systems, checking for
+ * execute access checks that the Java virtual machine has permission to
+ * search the directory in order to access file or subdirectories.
+ *
+ * <p> Depending on the implementation, this method may require to read file
+ * permissions, access control lists, or other file attributes in order to
+ * check the effective access to the file. Consequently, this method may not
+ * be atomic with respect to other file system operations.
+ *
+ * <p> Note that the result of this method is immediately outdated, there is
+ * no guarantee that a subsequent attempt to execute the file will succeed
+ * (or even that it will access the same file). Care should be taken when
+ * using this method in security sensitive applications.
+ *
+ * @param path
+ * the path to the file to check
+ *
+ * @return {@code true} if the file exists and is executable; {@code false}
+ * if the file does not exist, execute access would be denied because
+ * the Java virtual machine has insufficient privileges, or access
+ * cannot be determined
+ *
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkExec(String)
+ * checkExec} is invoked to check execute access to the file.
+ */
+ public static boolean isExecutable(Path path) {
+ return isAccessible(path, AccessMode.EXECUTE);
+ }
+
+ // -- Recursive operations --
+
+ /**
* Walks a file tree.
*
* <p> This method walks a file tree rooted at a given starting file. The
* file tree traversal is <em>depth-first</em> with the given {@link
* FileVisitor} invoked for each file encountered. File tree traversal
@@ -137,11 +2475,11 @@
* visit method returns a result of {@link FileVisitResult#TERMINATE
* TERMINATE}. Where a visit method terminates due an {@code IOException},
* an uncaught error, or runtime exception, then the traversal is terminated
* and the error or exception is propagated to the caller of this method.
*
- * <p> For each file encountered this method attempts to gets its {@link
+ * <p> For each file encountered this method attempts to read its {@link
* java.nio.file.attribute.BasicFileAttributes}. If the file is not a
* directory then the {@link FileVisitor#visitFile visitFile} method is
* invoked with the file attributes. If the file attributes cannot be read,
* due to an I/O exception, then the {@link FileVisitor#visitFileFailed
* visitFileFailed} method is invoked with the I/O exception.
@@ -172,11 +2510,11 @@
* FileVisitOption#FOLLOW_LINKS FOLLOW_LINKS} option then this method keeps
* track of directories visited so that cycles can be detected. A cycle
* arises when there is an entry in a directory that is an ancestor of the
* directory. Cycle detection is done by recording the {@link
* java.nio.file.attribute.BasicFileAttributes#fileKey file-key} of directories,
- * or if file keys are not available, by invoking the {@link Path#isSameFile
+ * or if file keys are not available, by invoking the {@link #isSameFile
* isSameFile} method to test if a directory is the same file as an
* ancestor. When a cycle is detected it is treated as an I/O error, and the
* {@link FileVisitor#visitFileFailed visitFileFailed} method is invoked with
* an instance of {@link FileSystemLoopException}.
*
@@ -195,37 +2533,40 @@
* <p> When a security manager is installed and it denies access to a file
* (or directory), then it is ignored and the visitor is not invoked for
* that file (or directory).
*
* @param start
- * The starting file
+ * the starting file
* @param options
- * Options to configure the traversal
+ * options to configure the traversal
* @param maxDepth
- * The maximum number of directory levels to visit
+ * the maximum number of directory levels to visit
* @param visitor
- * The file visitor to invoke for each file
+ * the file visitor to invoke for each file
*
+ * @return the starting file
+ *
* @throws IllegalArgumentException
- * If the {@code maxDepth} parameter is negative
+ * if the {@code maxDepth} parameter is negative
* @throws SecurityException
* If the security manager denies access to the starting file.
* In the case of the default provider, the {@link
* SecurityManager#checkRead(String) checkRead} method is invoked
* to check read access to the directory.
* @throws IOException
- * If an I/O error is thrown by a visitor method
+ * if an I/O error is thrown by a visitor method
*/
- public static void walkFileTree(Path start,
+ public static Path walkFileTree(Path start,
Set<FileVisitOption> options,
int maxDepth,
FileVisitor<? super Path> visitor)
throws IOException
{
if (maxDepth < 0)
throw new IllegalArgumentException("'maxDepth' is negative");
new FileTreeWalker(options, visitor, maxDepth).walk(start);
+ return start;
}
/**
* Walks a file tree.
*
@@ -232,132 +2573,529 @@
* <p> This method works as if invoking it were equivalent to evaluating the
* expression:
* <blockquote><pre>
* walkFileTree(start, EnumSet.noneOf(FileVisitOption.class), Integer.MAX_VALUE, visitor)
* </pre></blockquote>
+ * In other words, it does not follow symbolic links, and visits all levels
+ * of the file level.
*
* @param start
- * The starting file
+ * the starting file
* @param visitor
- * The file visitor to invoke for each file
+ * the file visitor to invoke for each file
*
+ * @return the starting file
+ *
* @throws SecurityException
* If the security manager denies access to the starting file.
* In the case of the default provider, the {@link
* SecurityManager#checkRead(String) checkRead} method is invoked
* to check read access to the directory.
* @throws IOException
- * If an I/O error is thrown by a visitor method
+ * if an I/O error is thrown by a visitor method
*/
- public static void walkFileTree(Path start, FileVisitor<? super Path> visitor)
+ public static Path walkFileTree(Path start, FileVisitor<? super Path> visitor)
throws IOException
{
- walkFileTree(start,
+ return walkFileTree(start,
EnumSet.noneOf(FileVisitOption.class),
Integer.MAX_VALUE,
visitor);
}
+
+ // -- Utility methods for simple usages --
+
+ // buffer size used for reading and writing
+ private static final int BUFFER_SIZE = 8192;
+
/**
- * Creates a directory by creating all nonexistent parent directories first.
+ * Opens a file for reading, returning a {@code BufferedReader} that may be
+ * used to read text from the file in an efficient manner. Bytes from the
+ * file are decoded into characters using the specified charset. Reading
+ * commences at the beginning of the file.
*
- * <p> The {@code attrs} parameter is an optional array of {@link FileAttribute
- * file-attributes} to set atomically when creating the nonexistent
- * directories. Each file attribute is identified by its {@link
- * FileAttribute#name name}. If more than one attribute of the same name is
- * included in the array then all but the last occurrence is ignored.
+ * <p> The {@code Reader} methods that read from the file throw {@code
+ * IOException} if a malformed or unmappable byte sequence is read.
*
- * <p> If this method fails, then it may do so after creating some, but not
- * all, of the parent directories.
+ * @param path
+ * the path to the file
+ * @param cs
+ * the charset to use for decoding
*
- * @param dir
- * the directory to create
+ * @return a new buffered reader, with default buffer size, to read text
+ * from the file
*
- * @param attrs
- * an optional list of file attributes to set atomically when
- * creating the directory
+ * @throws IOException
+ * if an I/O error occurs opening the file
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file.
*
- * @throws UnsupportedOperationException
- * if the array contains an attribute that cannot be set atomically
- * when creating the directory
- * @throws FileAlreadyExistsException
- * if {@code dir} exists but is not a directory <i>(optional specific
- * exception)</i>
+ * @see #readAllLines
+ */
+ public static BufferedReader newBufferedReader(Path path, Charset cs)
+ throws IOException
+ {
+ CharsetDecoder decoder = cs.newDecoder();
+ Reader reader = new InputStreamReader(newInputStream(path), decoder);
+ return new BufferedReader(reader);
+ }
+
+ /**
+ * Opens or creates a file for writing, returning a {@code BufferedWriter}
+ * that may be used to write text to the file in an efficient manner.
+ * The {@code options} parameter specifies how the the file is created or
+ * opened. If no options are present then this method works as if the {@link
+ * StandardOpenOption#CREATE CREATE}, {@link
+ * StandardOpenOption#TRUNCATE_EXISTING TRUNCATE_EXISTING}, and {@link
+ * StandardOpenOption#WRITE WRITE} options are present. In other words, it
+ * opens the file for writing, creating the file if it doesn't exist, or
+ * initially truncating an existing {@link #isRegularFile regular-file} to
+ * a size of {@code 0} if it exists.
+ *
+ * <p> The {@code Writer} methods to write text throw {@code IOException}
+ * if the text cannot be encoded using the specified charset.
+ *
+ * @param path
+ * the path to the file
+ * @param cs
+ * the charset to use for encoding
+ * @param options
+ * options specifying how the file is opened
+ *
+ * @return a new buffered writer, with default buffer size, to write text
+ * to the file
+ *
* @throws IOException
- * if an I/O error occurs
+ * if an I/O error occurs opening or creating the file
+ * @throws UnsupportedOperationException
+ * if an unsupported option is specified
* @throws SecurityException
- * in the case of the default provider, and a security manager is
+ * In the case of the default provider, and a security manager is
* installed, the {@link SecurityManager#checkWrite(String) checkWrite}
- * method is invoked prior to attempting to create a directory and
- * its {@link SecurityManager#checkRead(String) checkRead} is
- * invoked for each parent directory that is checked. If {@code
- * dir} is not an absolute path then its {@link Path#toAbsolutePath
- * toAbsolutePath} may need to be invoked to get its absolute path.
- * This may invoke the security manager's {@link
- * SecurityManager#checkPropertyAccess(String) checkPropertyAccess}
- * method to check access to the system property {@code user.dir}
+ * method is invoked to check write access to the file.
*
+ * @see #write(Path,Iterable,Charset,OpenOption[])
*/
- public static void createDirectories(Path dir, FileAttribute<?>... attrs)
+ public static BufferedWriter newBufferedWriter(Path path, Charset cs,
+ OpenOption... options)
throws IOException
{
- // attempt to create the directory
- try {
- createAndCheckIsDirectory(dir, attrs);
- return;
- } catch (FileAlreadyExistsException x) {
- // file exists and is not a directory
- throw x;
- } catch (IOException x) {
- // parent may not exist or other reason
+ CharsetEncoder encoder = cs.newEncoder();
+ Writer writer = new OutputStreamWriter(newOutputStream(path, options), encoder);
+ return new BufferedWriter(writer);
}
- // find existing parent (may require absolute path)
+ /**
+ * Reads all bytes from an input stream and writes them to an output stream.
+ */
+ private static long copy(InputStream source, OutputStream sink)
+ throws IOException
+ {
+ long nread = 0L;
+ byte[] buf = new byte[BUFFER_SIZE];
+ int n;
+ while ((n = source.read(buf)) > 0) {
+ sink.write(buf, 0, n);
+ nread += n;
+ }
+ return nread;
+ }
+
+ /**
+ * Copies all bytes from an input stream to a file. On return, the input
+ * stream will be at end of stream.
+ *
+ * <p> By default, the copy fails if the target file already exists or is a
+ * symbolic link. If the {@link StandardCopyOption#REPLACE_EXISTING
+ * REPLACE_EXISTING} option is specified, and the target file already exists,
+ * then it is replaced if it is not a non-empty directory. If the target
+ * file exists and is a symbolic link, then the symbolic link is replaced.
+ * In this release, the {@code REPLACE_EXISTING} option is the only option
+ * required to be supported by this method. Additional options may be
+ * supported in future releases.
+ *
+ * <p> If an I/O error occurs reading from the input stream or writing to
+ * the file, then it may do so after the target file has been created and
+ * after some bytes have been read or written. Consequently the input
+ * stream may not be at end of stream and may be in an inconsistent state.
+ * It is strongly recommended that the input stream be promptly closed if an
+ * I/O error occurs.
+ *
+ * <p> This method may block indefinitely reading from the input stream (or
+ * writing to the file). The behavior for the case that the input stream is
+ * <i>asynchronously closed</i> or the thread interrupted during the copy is
+ * highly input stream and file system provider specific and therefore not
+ * specified.
+ *
+ * <p> <b>Usage example</b>: Suppose we want to capture a web page and save
+ * it to a file:
+ * <pre>
+ * Path path = ...
+ * URI u = URI.create("http://java.sun.com/");
+ * try (InputStream in = u.toURL().openStream()) {
+ * Files.copy(in, path);
+ * }
+ * </pre>
+ *
+ * @param in
+ * the input stream to read from
+ * @param target
+ * the path to the file
+ * @param options
+ * options specifying how the copy should be done
+ *
+ * @return the number of bytes read or written
+ *
+ * @throws IOException
+ * if an I/O error occurs when reading or writing
+ * @throws FileAlreadyExistsException
+ * if the target file exists but cannot be replaced because the
+ * {@code REPLACE_EXISTING} option is not specified <i>(optional
+ * specific exception)</i>
+ * @throws DirectoryNotEmptyException
+ * the {@code REPLACE_EXISTING} option is specified but the file
+ * cannot be replaced because it is a non-empty directory
+ * <i>(optional specific exception)</i> *
+ * @throws UnsupportedOperationException
+ * if {@code options} contains a copy option that is not supported
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the file. Where the
+ * {@code REPLACE_EXISTING} option is specified, the security
+ * manager's {@link SecurityManager#checkDelete(String) checkDelete}
+ * method is invoked to check that an existing file can be deleted.
+ */
+ public static long copy(InputStream in, Path target, CopyOption... options)
+ throws IOException
+ {
+ // ensure not null before opening file
+ Objects.nonNull(in);
+
+ // check for REPLACE_EXISTING
+ boolean replaceExisting = false;
+ for (CopyOption opt: options) {
+ if (opt == StandardCopyOption.REPLACE_EXISTING) {
+ replaceExisting = true;
+ } else {
+ if (opt == null) {
+ throw new NullPointerException("options contains 'null'");
+ } else {
+ throw new UnsupportedOperationException(opt + " not supported");
+ }
+ }
+ }
+
+ // attempt to delete an existing file
SecurityException se = null;
+ if (replaceExisting) {
try {
- dir = dir.toAbsolutePath();
+ deleteIfExists(target);
} catch (SecurityException x) {
- // don't have permission to get absolute path
se = x;
}
- Path parent = dir.getParent();
- while (parent != null) {
+ }
+
+ // attempt to create target file. If it fails with
+ // FileAlreadyExistsException then it may be because the security
+ // manager prevented us from deleting the file, in which case we just
+ // throw the SecurityException.
+ OutputStream ostream;
try {
- parent.checkAccess();
+ ostream = newOutputStream(target, StandardOpenOption.CREATE_NEW,
+ StandardOpenOption.WRITE);
+ } catch (FileAlreadyExistsException x) {
+ if (se != null)
+ throw se;
+ // someone else won the race and created the file
+ throw x;
+ }
+
+ // do the copy
+ try (OutputStream out = ostream) {
+ return copy(in, out);
+ }
+ }
+
+ /**
+ * Copies all bytes from a file to an output stream.
+ *
+ * <p> If an I/O error occurs reading from the file or writing to the output
+ * stream, then it may do so after some bytes have been read or written.
+ * Consequently the output stream may be in an inconsistent state. It is
+ * strongly recommended that the output stream be promptly closed if an I/O
+ * error occurs.
+ *
+ * <p> This method may block indefinitely writing to the output stream (or
+ * reading from the file). The behavior for the case that the output stream
+ * is <i>asynchronously closed</i> or the thread interrupted during the copy
+ * is highly output stream and file system provider specific and therefore
+ * not specified.
+ *
+ * <p> Note that if the given output stream is {@link java.io.Flushable}
+ * then its {@link java.io.Flushable#flush flush} method may need to invoked
+ * after this method completes so as to flush any buffered output.
+ *
+ * @param source
+ * the path to the file
+ * @param out
+ * the output stream to write to
+ *
+ * @return the number of bytes read or written
+ *
+ * @throws IOException
+ * if an I/O error occurs when reading or writing
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file.
+ */
+ public static long copy(Path source, OutputStream out) throws IOException {
+ // ensure not null before opening file
+ Objects.nonNull(out);
+
+ try (InputStream in = newInputStream(source)) {
+ return copy(in, out);
+ }
+ }
+
+ /**
+ * Read all the bytes from an input stream. The {@code initialSize}
+ * parameter indicates the initial size of the byte[] to allocate.
+ */
+ private static byte[] read(InputStream source, int initialSize)
+ throws IOException
+ {
+ int capacity = initialSize;
+ byte[] buf = new byte[capacity];
+ int nread = 0;
+ int rem = buf.length;
+ int n;
+ // read to EOF which may read more or less than initialSize (eg: file
+ // is truncated while we are reading)
+ while ((n = source.read(buf, nread, rem)) > 0) {
+ nread += n;
+ rem -= n;
+ assert rem >= 0;
+ if (rem == 0) {
+ // need larger buffer
+ int newCapacity = capacity << 1;
+ if (newCapacity < 0) {
+ if (capacity == Integer.MAX_VALUE)
+ throw new OutOfMemoryError("Required array size too large");
+ newCapacity = Integer.MAX_VALUE;
+ }
+ rem = newCapacity - capacity;
+ buf = Arrays.copyOf(buf, newCapacity);
+ capacity = newCapacity;
+ }
+ }
+ return (capacity == nread) ? buf : Arrays.copyOf(buf, nread);
+ }
+
+ /**
+ * Read all the bytes from a file. The method ensures that the file is
+ * closed when all bytes have been read or an I/O error, or other runtime
+ * exception, is thrown.
+ *
+ * <p> Note that this method is intended for simple cases where it is
+ * convenient to read all bytes into a byte array. It is not intended for
+ * reading in large files.
+ *
+ * @param path
+ * the path to the file
+ *
+ * @return a byte array containing the bytes read from the file
+ *
+ * @throws IOException
+ * if an I/O error occurs reading from the stream
+ * @throws OutOfMemoryError
+ * if an array of the required size cannot be allocated, for
+ * example the file is larger that {@code 2GB}
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file.
+ */
+ public static byte[] readAllBytes(Path path) throws IOException {
+ long size = size(path);
+ if (size > (long)Integer.MAX_VALUE)
+ throw new OutOfMemoryError("Required array size too large");
+
+ try (InputStream in = newInputStream(path)) {
+ return read(in, (int)size);
+ }
+ }
+
+ /**
+ * Read all lines from a file. This method ensures that the file is
+ * closed when all bytes have been read or an I/O error, or other runtime
+ * exception, is thrown. Bytes from the file are decoded into characters
+ * using the specified charset.
+ *
+ * <p> This method recognizes the following as line terminators:
+ * <ul>
+ * <li> <code>\u000D</code> followed by <code>\u000A</code>,
+ * CARRIAGE RETURN followed by LINE FEED </li>
+ * <li> <code>\u000A</code>, LINE FEED </li>
+ * <li> <code>\u000D</code>, CARRIAGE RETURN </li>
+ * </ul>
+ * <p> Additional Unicode line terminators may be recognized in future
+ * releases.
+ *
+ * <p> Note that this method is intended for simple cases where it is
+ * convenient to read all lines in a single operation. It is not intended
+ * for reading in large files.
+ *
+ * @param path
+ * the path to the file
+ * @param cs
+ * the charset to use for decoding
+ *
+ * @return the lines from the file as a {@code List}; whether the {@code
+ * List} is modifiable or not is implementation dependent and
+ * therefore not specified
+ *
+ * @throws IOException
+ * if an I/O error occurs reading from the file or a malformed or
+ * unmappable byte sequence is read
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkRead(String) checkRead}
+ * method is invoked to check read access to the file.
+ *
+ * @see #newBufferedReader
+ */
+ public static List<String> readAllLines(Path path, Charset cs)
+ throws IOException
+ {
+ try (BufferedReader reader = newBufferedReader(path, cs)) {
+ List<String> result = new ArrayList<>();
+ for (;;) {
+ String line = reader.readLine();
+ if (line == null)
break;
- } catch (NoSuchFileException x) {
- // does not exist
+ result.add(line);
}
- parent = parent.getParent();
+ return result;
}
- if (parent == null) {
- // unable to find existing parent
- if (se != null)
- throw se;
- throw new IOException("Root directory does not exist");
}
- // create directories
- Path child = parent;
- for (Path name: parent.relativize(dir)) {
- child = child.resolve(name);
- createAndCheckIsDirectory(child, attrs);
+ /**
+ * Writes bytes to a file. The {@code options} parameter specifies how the
+ * the file is created or opened. If no options are present then this method
+ * works as if the {@link StandardOpenOption#CREATE CREATE}, {@link
+ * StandardOpenOption#TRUNCATE_EXISTING TRUNCATE_EXISTING}, and {@link
+ * StandardOpenOption#WRITE WRITE} options are present. In other words, it
+ * opens the file for writing, creating the file if it doesn't exist, or
+ * initially truncating an existing {@link #isRegularFile regular-file} to
+ * a size of {@code 0}. All bytes in the byte array are written to the file.
+ * The method ensures that the file is closed when all bytes have been
+ * written (or an I/O error or other runtime exception is thrown). If an I/O
+ * error occurs then it may do so after the file has created or truncated,
+ * or after some bytes have been written to the file.
+ *
+ * <p> <b>Usage example</b>: By default the method creates a new file or
+ * overrides an existing file. Suppose you instead want to append bytes
+ * to an existing file:
+ * <pre>
+ * Path path = ...
+ * byte[] bytes = ...
+ * Files.write(path, bytes, StandardOpenOption.APPEND);
+ * </pre>
+ *
+ * @param path
+ * the path to the file
+ * @param bytes
+ * the byte array with the bytes to write
+ * @param options
+ * options specifying how the file is opened
+ *
+ * @return the path
+ *
+ * @throws IOException
+ * if an I/O error occurs writing to or creating the file
+ * @throws UnsupportedOperationException
+ * if an unsupported option is specified
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the file.
+ */
+ public static Path write(Path path, byte[] bytes, OpenOption... options)
+ throws IOException
+ {
+ // ensure bytes is not null before opening file
+ Objects.nonNull(bytes);
+
+ try (OutputStream out = Files.newOutputStream(path, options)) {
+ int len = bytes.length;
+ int rem = len;
+ while (rem > 0) {
+ int n = Math.min(rem, BUFFER_SIZE);
+ out.write(bytes, (len-rem), n);
+ rem -= n;
}
}
+ return path;
+ }
/**
- * Attempts to create a directory. Does nothing if the directory already
- * exists.
+ * Write lines of text to a file. Each line is a char sequence and is
+ * written to the file in sequence with each line terminated by the
+ * platform's line separator, as defined by the system property {@code
+ * line.separator}. Characters are encoded into bytes using the specified
+ * charset.
+ *
+ * <p> The {@code options} parameter specifies how the the file is created
+ * or opened. If no options are present then this method works as if the
+ * {@link StandardOpenOption#CREATE CREATE}, {@link
+ * StandardOpenOption#TRUNCATE_EXISTING TRUNCATE_EXISTING}, and {@link
+ * StandardOpenOption#WRITE WRITE} options are present. In other words, it
+ * opens the file for writing, creating the file if it doesn't exist, or
+ * initially truncating an existing {@link #isRegularFile regular-file} to
+ * a size of {@code 0}. The method ensures that the file is closed when all
+ * lines have been written (or an I/O error or other runtime exception is
+ * thrown). If an I/O error occurs then it may do so after the file has
+ * created or truncated, or after some bytes have been written to the file.
+ *
+ * @param path
+ * the path to the file
+ * @param lines
+ * an object to iterate over the char sequences
+ * @param cs
+ * the charset to use for encoding
+ * @param options
+ * options specifying how the file is opened
+ *
+ * @return the path
+ *
+ * @throws IOException
+ * if an I/O error occurs writing to or creating the file, or the
+ * text cannot be encoded using the specified charset
+ * @throws UnsupportedOperationException
+ * if an unsupported option is specified
+ * @throws SecurityException
+ * In the case of the default provider, and a security manager is
+ * installed, the {@link SecurityManager#checkWrite(String) checkWrite}
+ * method is invoked to check write access to the file.
*/
- private static void createAndCheckIsDirectory(Path dir, FileAttribute<?>... attrs)
+ public static Path write(Path path, Iterable<? extends CharSequence> lines,
+ Charset cs, OpenOption... options)
throws IOException
{
- try {
- dir.createDirectory(attrs);
- } catch (FileAlreadyExistsException x) {
- boolean isDirectory = Attributes
- .readBasicFileAttributes(dir, LinkOption.NOFOLLOW_LINKS).isDirectory();
- if (!isDirectory)
- throw x;
+ // ensure lines is not null before opening file
+ Objects.nonNull(lines);
+ CharsetEncoder encoder = cs.newEncoder();
+ OutputStream out = newOutputStream(path, options);
+ try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, encoder))) {
+ for (CharSequence line: lines) {
+ writer.append(line);
+ writer.newLine();
}
}
+ return path;
+ }
}