9 * by Oracle in the LICENSE file that accompanied this code.
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 <code>FileInputStream</code> obtains input bytes
34 * from a file in a file system. What files
35 * are available depends on the host environment.
36 *
37 * <p><code>FileInputStream</code> is meant for reading streams of raw bytes
38 * such as image data. For reading streams of characters, consider using
39 * <code>FileReader</code>.
40 *
41 * @author Arthur van Hoff
42 * @see java.io.File
43 * @see java.io.FileDescriptor
44 * @see java.io.FileOutputStream
45 * @see java.nio.file.Files#newInputStream
46 * @since 1.0
47 */
48 public
49 class FileInputStream extends InputStream
50 {
51 /* File Descriptor - handle to the open file */
52 private final FileDescriptor fd;
53
54 /**
55 * The path of the referenced file
56 * (null if the stream is created with a file descriptor)
57 */
58 private final String path;
59
60 private FileChannel channel = null;
61
62 private final Object closeLock = new Object();
63 private volatile boolean closed = false;
64
65 /**
66 * Creates a <code>FileInputStream</code> by
67 * opening a connection to an actual file,
68 * the file named by the path name <code>name</code>
69 * in the file system. A new <code>FileDescriptor</code>
70 * object is created to represent this file
71 * connection.
72 * <p>
73 * First, if there is a security
74 * manager, its <code>checkRead</code> method
75 * is called with the <code>name</code> argument
76 * as its argument.
77 * <p>
78 * If the named file does not exist, is a directory rather than a regular
79 * file, or for some other reason cannot be opened for reading then a
80 * <code>FileNotFoundException</code> is thrown.
81 *
82 * @param name the system-dependent file name.
83 * @exception FileNotFoundException if the file does not exist,
296 * @return an estimate of the number of remaining bytes that can be read
297 * (or skipped over) from this input stream without blocking.
298 * @exception IOException if this file input stream has been closed by calling
299 * {@code close} or an I/O error occurs.
300 */
301 public native int available() throws IOException;
302
303 /**
304 * Closes this file input stream and releases any system resources
305 * associated with the stream.
306 *
307 * <p> If this stream has an associated channel then the channel is closed
308 * as well.
309 *
310 * @exception IOException if an I/O error occurs.
311 *
312 * @revised 1.4
313 * @spec JSR-51
314 */
315 public void close() throws IOException {
316 synchronized (closeLock) {
317 if (closed) {
318 return;
319 }
320 closed = true;
321 }
322 if (channel != null) {
323 channel.close();
324 }
325
326 fd.closeAll(new Closeable() {
327 public void close() throws IOException {
328 close0();
329 }
330 });
331 }
332
333 /**
334 * Returns the <code>FileDescriptor</code>
335 * object that represents the connection to
336 * the actual file in the file system being
337 * used by this <code>FileInputStream</code>.
338 *
339 * @return the file descriptor object associated with this stream.
340 * @exception IOException if an I/O error occurs.
341 * @see java.io.FileDescriptor
350 /**
351 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
352 * object associated with this file input stream.
353 *
354 * <p> The initial {@link java.nio.channels.FileChannel#position()
355 * position} of the returned channel will be equal to the
356 * number of bytes read from the file so far. Reading bytes from this
357 * stream will increment the channel's position. Changing the channel's
358 * position, either explicitly or by reading, will change this stream's
359 * file position.
360 *
361 * @return the file channel associated with this file input stream
362 *
363 * @since 1.4
364 * @spec JSR-51
365 */
366 public FileChannel getChannel() {
367 synchronized (this) {
368 if (channel == null) {
369 channel = FileChannelImpl.open(fd, path, true, false, this);
370 }
371 return channel;
372 }
373 }
374
375 private static native void initIDs();
376
377 private native void close0() throws IOException;
378
379 static {
380 initIDs();
381 }
382
383 /**
384 * Ensures that the <code>close</code> method of this file input stream is
385 * called when there are no more references to it.
386 *
387 * @exception IOException if an I/O error occurs.
388 * @see java.io.FileInputStream#close()
389 */
|
9 * by Oracle in the LICENSE file that accompanied this code.
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 java.util.concurrent.atomic.AtomicBoolean;
30 import sun.nio.ch.FileChannelImpl;
31
32
33 /**
34 * A <code>FileInputStream</code> obtains input bytes
35 * from a file in a file system. What files
36 * are available depends on the host environment.
37 *
38 * <p><code>FileInputStream</code> is meant for reading streams of raw bytes
39 * such as image data. For reading streams of characters, consider using
40 * <code>FileReader</code>.
41 *
42 * @author Arthur van Hoff
43 * @see java.io.File
44 * @see java.io.FileDescriptor
45 * @see java.io.FileOutputStream
46 * @see java.nio.file.Files#newInputStream
47 * @since 1.0
48 */
49 public
50 class FileInputStream extends InputStream
51 {
52 /* File Descriptor - handle to the open file */
53 private final FileDescriptor fd;
54
55 /**
56 * The path of the referenced file
57 * (null if the stream is created with a file descriptor)
58 */
59 private final String path;
60
61 private FileChannel channel = null;
62
63 private AtomicBoolean closed = new AtomicBoolean(false);
64
65 /**
66 * Creates a <code>FileInputStream</code> by
67 * opening a connection to an actual file,
68 * the file named by the path name <code>name</code>
69 * in the file system. A new <code>FileDescriptor</code>
70 * object is created to represent this file
71 * connection.
72 * <p>
73 * First, if there is a security
74 * manager, its <code>checkRead</code> method
75 * is called with the <code>name</code> argument
76 * as its argument.
77 * <p>
78 * If the named file does not exist, is a directory rather than a regular
79 * file, or for some other reason cannot be opened for reading then a
80 * <code>FileNotFoundException</code> is thrown.
81 *
82 * @param name the system-dependent file name.
83 * @exception FileNotFoundException if the file does not exist,
296 * @return an estimate of the number of remaining bytes that can be read
297 * (or skipped over) from this input stream without blocking.
298 * @exception IOException if this file input stream has been closed by calling
299 * {@code close} or an I/O error occurs.
300 */
301 public native int available() throws IOException;
302
303 /**
304 * Closes this file input stream and releases any system resources
305 * associated with the stream.
306 *
307 * <p> If this stream has an associated channel then the channel is closed
308 * as well.
309 *
310 * @exception IOException if an I/O error occurs.
311 *
312 * @revised 1.4
313 * @spec JSR-51
314 */
315 public void close() throws IOException {
316 if (!closed.compareAndSet(false, true)) {
317 // if compareAndSet() returns false closed was already true
318 return;
319 }
320
321 if (channel != null) {
322 channel.close();
323 }
324
325 fd.closeAll(new Closeable() {
326 public void close() throws IOException {
327 close0();
328 }
329 });
330 }
331
332 /**
333 * Returns the <code>FileDescriptor</code>
334 * object that represents the connection to
335 * the actual file in the file system being
336 * used by this <code>FileInputStream</code>.
337 *
338 * @return the file descriptor object associated with this stream.
339 * @exception IOException if an I/O error occurs.
340 * @see java.io.FileDescriptor
349 /**
350 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
351 * object associated with this file input stream.
352 *
353 * <p> The initial {@link java.nio.channels.FileChannel#position()
354 * position} of the returned channel will be equal to the
355 * number of bytes read from the file so far. Reading bytes from this
356 * stream will increment the channel's position. Changing the channel's
357 * position, either explicitly or by reading, will change this stream's
358 * file position.
359 *
360 * @return the file channel associated with this file input stream
361 *
362 * @since 1.4
363 * @spec JSR-51
364 */
365 public FileChannel getChannel() {
366 synchronized (this) {
367 if (channel == null) {
368 channel = FileChannelImpl.open(fd, path, true, false, this);
369 if (closed.get()) {
370 try {
371 channel.close();
372 } catch (IOException ioe) {
373 throw new InternalError(ioe); // should not happen
374 }
375 }
376 }
377 return channel;
378 }
379 }
380
381 private static native void initIDs();
382
383 private native void close0() throws IOException;
384
385 static {
386 initIDs();
387 }
388
389 /**
390 * Ensures that the <code>close</code> method of this file input stream is
391 * called when there are no more references to it.
392 *
393 * @exception IOException if an I/O error occurs.
394 * @see java.io.FileInputStream#close()
395 */
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