10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.io;
27
28 import java.nio.channels.FileChannel;
29 import sun.nio.ch.FileChannelImpl;
30
31
32 /**
33 * A file output stream is an output stream for writing data to a
34 * <code>File</code> or to a <code>FileDescriptor</code>. Whether or not
35 * a file is available or may be created depends upon the underlying
36 * platform. Some platforms, in particular, allow a file to be opened
37 * for writing by only one <tt>FileOutputStream</tt> (or other
38 * file-writing object) at a time. In such situations the constructors in
39 * this class will fail if the file involved is already open.
40 *
41 * <p><code>FileOutputStream</code> is meant for writing streams of raw bytes
42 * such as image data. For writing streams of characters, consider using
43 * <code>FileWriter</code>.
44 *
45 * @author Arthur van Hoff
46 * @see java.io.File
47 * @see java.io.FileDescriptor
48 * @see java.io.FileInputStream
49 * @see java.nio.file.Files#newOutputStream
50 * @since JDK1.0
51 */
52 public
53 class FileOutputStream extends OutputStream
54 {
55 /**
56 * The system dependent file descriptor.
57 */
58 private final FileDescriptor fd;
59
60 /**
61 * True if the file is opened for append.
62 */
63 private final boolean append;
64
65 /**
66 * The associated channel, initialized lazily.
67 */
68 private FileChannel channel;
69
70 private final Object closeLock = new Object();
71 private volatile boolean closed = false;
72
73 /**
74 * Creates a file output stream to write to the file with the
75 * specified name. A new <code>FileDescriptor</code> object is
76 * created to represent this file connection.
77 * <p>
78 * First, if there is a security manager, its <code>checkWrite</code>
79 * method is called with <code>name</code> as its argument.
80 * <p>
182 * to the file.
183 * @see java.io.File#getPath()
184 * @see java.lang.SecurityException
185 * @see java.lang.SecurityManager#checkWrite(java.lang.String)
186 * @since 1.4
187 */
188 public FileOutputStream(File file, boolean append)
189 throws FileNotFoundException
190 {
191 String name = (file != null ? file.getPath() : null);
192 SecurityManager security = System.getSecurityManager();
193 if (security != null) {
194 security.checkWrite(name);
195 }
196 if (name == null) {
197 throw new NullPointerException();
198 }
199 this.fd = new FileDescriptor();
200 fd.attach(this);
201 this.append = append;
202
203 open(name, append);
204 }
205
206 /**
207 * Creates a file output stream to write to the specified file
208 * descriptor, which represents an existing connection to an actual
209 * file in the file system.
210 * <p>
211 * First, if there is a security manager, its <code>checkWrite</code>
212 * method is called with the file descriptor <code>fdObj</code>
213 * argument as its argument.
214 * <p>
215 * If <code>fdObj</code> is null then a <code>NullPointerException</code>
216 * is thrown.
217 * <p>
218 * This constructor does not throw an exception if <code>fdObj</code>
219 * is {@link java.io.FileDescriptor#valid() invalid}.
220 * However, if the methods are invoked on the resulting stream to attempt
221 * I/O on the stream, an <code>IOException</code> is thrown.
222 *
223 * @param fdObj the file descriptor to be opened for writing
224 * @exception SecurityException if a security manager exists and its
225 * <code>checkWrite</code> method denies
226 * write access to the file descriptor
227 * @see java.lang.SecurityManager#checkWrite(java.io.FileDescriptor)
228 */
229 public FileOutputStream(FileDescriptor fdObj) {
230 SecurityManager security = System.getSecurityManager();
231 if (fdObj == null) {
232 throw new NullPointerException();
233 }
234 if (security != null) {
235 security.checkWrite(fdObj);
236 }
237 this.fd = fdObj;
238 this.append = false;
239
240 fd.attach(this);
241 }
242
243 /**
244 * Opens a file, with the specified name, for overwriting or appending.
245 * @param name name of file to be opened
246 * @param append whether the file is to be opened in append mode
247 */
248 private native void open(String name, boolean append)
249 throws FileNotFoundException;
250
251 /**
252 * Writes the specified byte to this file output stream.
253 *
254 * @param b the byte to be written.
255 * @param append {@code true} if the write operation first
256 * advances the position to the end of file
257 */
258 private native void write(int b, boolean append) throws IOException;
259
260 /**
261 * Writes the specified byte to this file output stream. Implements
262 * the <code>write</code> method of <code>OutputStream</code>.
263 *
264 * @param b the byte to be written.
265 * @exception IOException if an I/O error occurs.
266 */
267 public void write(int b) throws IOException {
268 write(b, append);
269 }
270
271 /**
272 * Writes a sub array as a sequence of bytes.
273 * @param b the data to be written
274 * @param off the start offset in the data
275 * @param len the number of bytes that are written
276 * @param append {@code true} to first advance the position to the
277 * end of file
278 * @exception IOException If an I/O error has occurred.
279 */
280 private native void writeBytes(byte b[], int off, int len, boolean append)
281 throws IOException;
282
283 /**
284 * Writes <code>b.length</code> bytes from the specified byte array
285 * to this file output stream.
286 *
287 * @param b the data.
288 * @exception IOException if an I/O error occurs.
289 */
290 public void write(byte b[]) throws IOException {
291 writeBytes(b, 0, b.length, append);
292 }
293
294 /**
295 * Writes <code>len</code> bytes from the specified byte array
296 * starting at offset <code>off</code> to this file output stream.
297 *
298 * @param b the data.
299 * @param off the start offset in the data.
300 * @param len the number of bytes to write.
301 * @exception IOException if an I/O error occurs.
302 */
303 public void write(byte b[], int off, int len) throws IOException {
304 writeBytes(b, off, len, append);
305 }
306
307 /**
308 * Closes this file output stream and releases any system resources
309 * associated with this stream. This file output stream may no longer
310 * be used for writing bytes.
311 *
312 * <p> If this stream has an associated channel then the channel is closed
313 * as well.
314 *
315 * @exception IOException if an I/O error occurs.
316 *
317 * @revised 1.4
318 * @spec JSR-51
319 */
320 public void close() throws IOException {
321 synchronized (closeLock) {
322 if (closed) {
323 return;
324 }
356 /**
357 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
358 * object associated with this file output stream. </p>
359 *
360 * <p> The initial {@link java.nio.channels.FileChannel#position()
361 * </code>position<code>} of the returned channel will be equal to the
362 * number of bytes written to the file so far unless this stream is in
363 * append mode, in which case it will be equal to the size of the file.
364 * Writing bytes to this stream will increment the channel's position
365 * accordingly. Changing the channel's position, either explicitly or by
366 * writing, will change this stream's file position.
367 *
368 * @return the file channel associated with this file output stream
369 *
370 * @since 1.4
371 * @spec JSR-51
372 */
373 public FileChannel getChannel() {
374 synchronized (this) {
375 if (channel == null) {
376 channel = FileChannelImpl.open(fd, false, true, append, this);
377 }
378 return channel;
379 }
380 }
381
382 /**
383 * Cleans up the connection to the file, and ensures that the
384 * <code>close</code> method of this file output stream is
385 * called when there are no more references to this stream.
386 *
387 * @exception IOException if an I/O error occurs.
388 * @see java.io.FileInputStream#close()
389 */
390 protected void finalize() throws IOException {
391 if (fd != null) {
392 if (fd == FileDescriptor.out || fd == FileDescriptor.err) {
393 flush();
394 } else {
395 /* if fd is shared, the references in FileDescriptor
396 * will ensure that finalizer is only called when
|
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.io;
27
28 import java.nio.channels.FileChannel;
29 import sun.nio.ch.FileChannelImpl;
30 import sun.misc.IoTrace;
31
32
33 /**
34 * A file output stream is an output stream for writing data to a
35 * <code>File</code> or to a <code>FileDescriptor</code>. Whether or not
36 * a file is available or may be created depends upon the underlying
37 * platform. Some platforms, in particular, allow a file to be opened
38 * for writing by only one <tt>FileOutputStream</tt> (or other
39 * file-writing object) at a time. In such situations the constructors in
40 * this class will fail if the file involved is already open.
41 *
42 * <p><code>FileOutputStream</code> is meant for writing streams of raw bytes
43 * such as image data. For writing streams of characters, consider using
44 * <code>FileWriter</code>.
45 *
46 * @author Arthur van Hoff
47 * @see java.io.File
48 * @see java.io.FileDescriptor
49 * @see java.io.FileInputStream
50 * @see java.nio.file.Files#newOutputStream
51 * @since JDK1.0
52 */
53 public
54 class FileOutputStream extends OutputStream
55 {
56 /**
57 * The system dependent file descriptor.
58 */
59 private final FileDescriptor fd;
60
61 /**
62 * The path of the referenced file (null if there is no file)
63 */
64 private final String path;
65
66 /**
67 * True if the file is opened for append.
68 */
69 private final boolean append;
70
71 /**
72 * The associated channel, initialized lazily.
73 */
74 private FileChannel channel;
75
76 private final Object closeLock = new Object();
77 private volatile boolean closed = false;
78
79 /**
80 * Creates a file output stream to write to the file with the
81 * specified name. A new <code>FileDescriptor</code> object is
82 * created to represent this file connection.
83 * <p>
84 * First, if there is a security manager, its <code>checkWrite</code>
85 * method is called with <code>name</code> as its argument.
86 * <p>
188 * to the file.
189 * @see java.io.File#getPath()
190 * @see java.lang.SecurityException
191 * @see java.lang.SecurityManager#checkWrite(java.lang.String)
192 * @since 1.4
193 */
194 public FileOutputStream(File file, boolean append)
195 throws FileNotFoundException
196 {
197 String name = (file != null ? file.getPath() : null);
198 SecurityManager security = System.getSecurityManager();
199 if (security != null) {
200 security.checkWrite(name);
201 }
202 if (name == null) {
203 throw new NullPointerException();
204 }
205 this.fd = new FileDescriptor();
206 fd.attach(this);
207 this.append = append;
208 this.path = name;
209 open(name, append);
210 }
211
212 /**
213 * Creates a file output stream to write to the specified file
214 * descriptor, which represents an existing connection to an actual
215 * file in the file system.
216 * <p>
217 * First, if there is a security manager, its <code>checkWrite</code>
218 * method is called with the file descriptor <code>fdObj</code>
219 * argument as its argument.
220 * <p>
221 * If <code>fdObj</code> is null then a <code>NullPointerException</code>
222 * is thrown.
223 * <p>
224 * This constructor does not throw an exception if <code>fdObj</code>
225 * is {@link java.io.FileDescriptor#valid() invalid}.
226 * However, if the methods are invoked on the resulting stream to attempt
227 * I/O on the stream, an <code>IOException</code> is thrown.
228 *
229 * @param fdObj the file descriptor to be opened for writing
230 * @exception SecurityException if a security manager exists and its
231 * <code>checkWrite</code> method denies
232 * write access to the file descriptor
233 * @see java.lang.SecurityManager#checkWrite(java.io.FileDescriptor)
234 */
235 public FileOutputStream(FileDescriptor fdObj) {
236 SecurityManager security = System.getSecurityManager();
237 if (fdObj == null) {
238 throw new NullPointerException();
239 }
240 if (security != null) {
241 security.checkWrite(fdObj);
242 }
243 this.fd = fdObj;
244 this.path = null;
245 this.append = false;
246
247 fd.attach(this);
248 }
249
250 /**
251 * Opens a file, with the specified name, for overwriting or appending.
252 * @param name name of file to be opened
253 * @param append whether the file is to be opened in append mode
254 */
255 private native void open(String name, boolean append)
256 throws FileNotFoundException;
257
258 /**
259 * Writes the specified byte to this file output stream.
260 *
261 * @param b the byte to be written.
262 * @param append {@code true} if the write operation first
263 * advances the position to the end of file
264 */
265 private native void write(int b, boolean append) throws IOException;
266
267 /**
268 * Writes the specified byte to this file output stream. Implements
269 * the <code>write</code> method of <code>OutputStream</code>.
270 *
271 * @param b the byte to be written.
272 * @exception IOException if an I/O error occurs.
273 */
274 public void write(int b) throws IOException {
275 Object traceHandle = IoTrace.fileWriteBegin(path);
276 write(b, append);
277 IoTrace.fileWriteEnd(traceHandle, 1);
278 }
279
280 /**
281 * Writes a sub array as a sequence of bytes.
282 * @param b the data to be written
283 * @param off the start offset in the data
284 * @param len the number of bytes that are written
285 * @param append {@code true} to first advance the position to the
286 * end of file
287 * @exception IOException If an I/O error has occurred.
288 */
289 private native void writeBytes(byte b[], int off, int len, boolean append)
290 throws IOException;
291
292 /**
293 * Writes <code>b.length</code> bytes from the specified byte array
294 * to this file output stream.
295 *
296 * @param b the data.
297 * @exception IOException if an I/O error occurs.
298 */
299 public void write(byte b[]) throws IOException {
300 Object traceHandle = IoTrace.fileWriteBegin(path);
301 writeBytes(b, 0, b.length, append);
302 IoTrace.fileWriteEnd(traceHandle, b.length);
303 }
304
305 /**
306 * Writes <code>len</code> bytes from the specified byte array
307 * starting at offset <code>off</code> to this file output stream.
308 *
309 * @param b the data.
310 * @param off the start offset in the data.
311 * @param len the number of bytes to write.
312 * @exception IOException if an I/O error occurs.
313 */
314 public void write(byte b[], int off, int len) throws IOException {
315 Object traceHandle = IoTrace.fileWriteBegin(path);
316 writeBytes(b, off, len, append);
317 IoTrace.fileWriteEnd(traceHandle, len);
318 }
319
320 /**
321 * Closes this file output stream and releases any system resources
322 * associated with this stream. This file output stream may no longer
323 * be used for writing bytes.
324 *
325 * <p> If this stream has an associated channel then the channel is closed
326 * as well.
327 *
328 * @exception IOException if an I/O error occurs.
329 *
330 * @revised 1.4
331 * @spec JSR-51
332 */
333 public void close() throws IOException {
334 synchronized (closeLock) {
335 if (closed) {
336 return;
337 }
369 /**
370 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
371 * object associated with this file output stream. </p>
372 *
373 * <p> The initial {@link java.nio.channels.FileChannel#position()
374 * </code>position<code>} of the returned channel will be equal to the
375 * number of bytes written to the file so far unless this stream is in
376 * append mode, in which case it will be equal to the size of the file.
377 * Writing bytes to this stream will increment the channel's position
378 * accordingly. Changing the channel's position, either explicitly or by
379 * writing, will change this stream's file position.
380 *
381 * @return the file channel associated with this file output stream
382 *
383 * @since 1.4
384 * @spec JSR-51
385 */
386 public FileChannel getChannel() {
387 synchronized (this) {
388 if (channel == null) {
389 channel = FileChannelImpl.open(fd, path, false, true, append, this);
390 }
391 return channel;
392 }
393 }
394
395 /**
396 * Cleans up the connection to the file, and ensures that the
397 * <code>close</code> method of this file output stream is
398 * called when there are no more references to this stream.
399 *
400 * @exception IOException if an I/O error occurs.
401 * @see java.io.FileInputStream#close()
402 */
403 protected void finalize() throws IOException {
404 if (fd != null) {
405 if (fd == FileDescriptor.out || fd == FileDescriptor.err) {
406 flush();
407 } else {
408 /* if fd is shared, the references in FileDescriptor
409 * will ensure that finalizer is only called when
|