/* * Copyright 2007-2009 Sun Microsystems, Inc. All Rights Reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Sun designates this * particular file as subject to the "Classpath" exception as provided * by Sun in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. */ package java.nio.file; import java.nio.file.attribute.*; import java.util.Map; import java.io.InputStream; import java.io.OutputStream; import java.io.IOException; /** * A reference to a file. * *
A {@code FileRef} is an object that locates a file and defines methods to * open the file for reading or writing. It also provides access to associated * metadata or file attributes. * * @since 1.7 * @see java.nio.file.attribute.Attributes * @see java.io.File#toPath */ public interface FileRef { /** * Opens the file referenced by this object, 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. * *
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. * * @return an input stream to read bytes from the file * * @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. */ InputStream newInputStream(OpenOption... options) throws IOException; /** * Opens or creates the file located by this object for writing, returning * an output stream to write bytes to the file. * *
The {@code options} parameter determines how the file is opened. * If no options are present then this method creates a new file for writing * or truncates an existing file. In addition to the {@link StandardOpenOption * standard} options, an implementation may also support additional * implementation specific options. * *
The resulting stream will not be buffered. The stream will be safe * for access by multiple concurrent threads. * * @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. */ OutputStream newOutputStream(OpenOption... options) throws IOException; /** * Returns a file attribute view of a given type. * *
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. * *
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.
*
* @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
*
* @throws UnsupportedOperationException
* If options contains an unsupported option. This exception is
* specified to allow the {@code LinkOption} enum be extended
* in future releases.
*
* @see Attributes#readBasicFileAttributes
*/
The {@code attribute} parameter identifies the attribute to be set
* and takes the form:
* view-name 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. attribute-name is the name of the attribute
* within the set.
*
* Usage Example:
* Suppose we want to set the DOS "hidden" attribute:
* The {@code attribute} parameter identifies the attribute to be read
* and takes the form:
* view-name 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. attribute-name is the name of the attribute.
*
* 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 and so
* the method returns the file attribute of the symbolic link.
*
* Usage Example:
* Suppose we require the user ID of the file owner on a system that
* supports a "{@code unix}" view:
* The {@code attributes} parameter identifies the attributes to be read
* and takes the form:
* view-name 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.
*
* The attribute-list 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.
*
* The following examples demonstrate possible values for the {@code
* attributes} parameter:
*
* 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 and so
* the method returns the file attribute of the symbolic link.
*
* @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.
*/
Map
* [view-name:]attribute-name
*
* where square brackets [...] delineate an optional component and the
* character {@code ':'} stands for itself.
*
*
* file.setAttribute("dos:hidden", true);
*
*
* @param attribute
* the attribute to set
* @param value
* the attribute value
* @param options
* options indicating how symbolic links are handled
*
* @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.
*/
void setAttribute(String attribute, Object value, LinkOption... options)
throws IOException;
/**
* Reads the value of a file attribute.
*
*
* [view-name:]attribute-name
*
* where square brackets [...] delineate an optional component and the
* character {@code ':'} stands for itself.
*
*
* int uid = (Integer)file.getAttribute("unix:uid");
*
*
* @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
*
* 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.
*/
Object getAttribute(String attribute, LinkOption... options) throws IOException;
/**
* Reads a set of file attributes as a bulk operation.
*
*
* [view-name:]attribute-list
*
* where square brackets [...] delineate an optional component and the
* character {@code ':'} stands for itself.
*
*
*
*
*
*
*
*
* {@code "*"}
* Read all {@link BasicFileAttributes basic-file-attributes}.
*
*
* {@code "size,lastModifiedTime,lastAccessTime"}
* Reads the file size, last modified time, and last access time
* attributes.
*
*
* {@code "posix:*"}
* Read all {@link PosixFileAttributes POSIX-file-attributes}..
*
*
* {@code "posix:permissions,owner,size"}
* Reads the POSX file permissions, owner, and file size.
*