107 * @param file the file to be opened for reading.
108 * @exception FileNotFoundException if the file does not exist,
109 * is a directory rather than a regular file,
110 * or for some other reason cannot be opened for
111 * reading.
112 * @exception SecurityException if a security manager exists and its
113 * <code>checkRead</code> method denies read access to the file.
114 * @see java.io.File#getPath()
115 * @see java.lang.SecurityManager#checkRead(java.lang.String)
116 */
117 public FileInputStream(File file) throws FileNotFoundException {
118 String name = (file != null ? file.getPath() : null);
119 SecurityManager security = System.getSecurityManager();
120 if (security != null) {
121 security.checkRead(name);
122 }
123 if (name == null) {
124 throw new NullPointerException();
125 }
126 fd = new FileDescriptor();
127 fd.incrementAndGetUseCount();
128 open(name);
129 }
130
131 /**
132 * Creates a <code>FileInputStream</code> by using the file descriptor
133 * <code>fdObj</code>, which represents an existing connection to an
134 * actual file in the file system.
135 * <p>
136 * If there is a security manager, its <code>checkRead</code> method is
137 * called with the file descriptor <code>fdObj</code> as its argument to
138 * see if it's ok to read the file descriptor. If read access is denied
139 * to the file descriptor a <code>SecurityException</code> is thrown.
140 * <p>
141 * If <code>fdObj</code> is null then a <code>NullPointerException</code>
142 * is thrown.
143 * <p>
144 * This constructor does not throw an exception if <code>fdObj</code>
145 * is {@link java.io.FileDescriptor#valid() invalid}.
146 * However, if the methods are invoked on the resulting stream to attempt
147 * I/O on the stream, an <code>IOException</code> is thrown.
148 *
149 * @param fdObj the file descriptor to be opened for reading.
150 * @throws SecurityException if a security manager exists and its
151 * <code>checkRead</code> method denies read access to the
152 * file descriptor.
153 * @see SecurityManager#checkRead(java.io.FileDescriptor)
154 */
155 public FileInputStream(FileDescriptor fdObj) {
156 SecurityManager security = System.getSecurityManager();
157 if (fdObj == null) {
158 throw new NullPointerException();
159 }
160 if (security != null) {
161 security.checkRead(fdObj);
162 }
163 fd = fdObj;
164
165 /*
166 * FileDescriptor is being shared by streams.
167 * Ensure that it's GC'ed only when all the streams/channels are done
168 * using it.
169 */
170 fd.incrementAndGetUseCount();
171 }
172
173 /**
174 * Opens the specified file for reading.
175 * @param name the name of the file
176 */
177 private native void open(String name) throws FileNotFoundException;
178
179 /**
180 * Reads a byte of data from this input stream. This method blocks
181 * if no input is yet available.
182 *
183 * @return the next byte of data, or <code>-1</code> if the end of the
184 * file is reached.
185 * @exception IOException if an I/O error occurs.
186 */
187 public native int read() throws IOException;
188
189 /**
190 * Reads a subarray as a sequence of bytes.
277 /**
278 * Closes this file input stream and releases any system resources
279 * associated with the stream.
280 *
281 * <p> If this stream has an associated channel then the channel is closed
282 * as well.
283 *
284 * @exception IOException if an I/O error occurs.
285 *
286 * @revised 1.4
287 * @spec JSR-51
288 */
289 public void close() throws IOException {
290 synchronized (closeLock) {
291 if (closed) {
292 return;
293 }
294 closed = true;
295 }
296 if (channel != null) {
297 /*
298 * Decrement the FD use count associated with the channel
299 * The use count is incremented whenever a new channel
300 * is obtained from this stream.
301 */
302 fd.decrementAndGetUseCount();
303 channel.close();
304 }
305
306 /*
307 * Decrement the FD use count associated with this stream
308 */
309 int useCount = fd.decrementAndGetUseCount();
310
311 /*
312 * If FileDescriptor is still in use by another stream, we
313 * will not close it.
314 */
315 if (useCount <= 0) {
316 close0();
317 }
318 }
319
320 /**
321 * Returns the <code>FileDescriptor</code>
322 * object that represents the connection to
323 * the actual file in the file system being
324 * used by this <code>FileInputStream</code>.
325 *
326 * @return the file descriptor object associated with this stream.
327 * @exception IOException if an I/O error occurs.
328 * @see java.io.FileDescriptor
329 */
330 public final FileDescriptor getFD() throws IOException {
331 if (fd != null) return fd;
332 throw new IOException();
333 }
334
335 /**
336 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
337 * object associated with this file input stream.
338 *
339 * <p> The initial {@link java.nio.channels.FileChannel#position()
340 * </code>position<code>} of the returned channel will be equal to the
341 * number of bytes read from the file so far. Reading bytes from this
342 * stream will increment the channel's position. Changing the channel's
343 * position, either explicitly or by reading, will change this stream's
344 * file position.
345 *
346 * @return the file channel associated with this file input stream
347 *
348 * @since 1.4
349 * @spec JSR-51
350 */
351 public FileChannel getChannel() {
352 synchronized (this) {
353 if (channel == null) {
354 channel = FileChannelImpl.open(fd, true, false, this);
355
356 /*
357 * Increment fd's use count. Invoking the channel's close()
358 * method will result in decrementing the use count set for
359 * the channel.
360 */
361 fd.incrementAndGetUseCount();
362 }
363 return channel;
364 }
365 }
366
367 private static native void initIDs();
368
369 private native void close0() throws IOException;
370
371 static {
372 initIDs();
373 }
374
375 /**
376 * Ensures that the <code>close</code> method of this file input stream is
377 * called when there are no more references to it.
378 *
379 * @exception IOException if an I/O error occurs.
380 * @see java.io.FileInputStream#close()
381 */
382 protected void finalize() throws IOException {
383 if ((fd != null) && (fd != FileDescriptor.in)) {
384 close();
385 }
386 }
387 }
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107 * @param file the file to be opened for reading.
108 * @exception FileNotFoundException if the file does not exist,
109 * is a directory rather than a regular file,
110 * or for some other reason cannot be opened for
111 * reading.
112 * @exception SecurityException if a security manager exists and its
113 * <code>checkRead</code> method denies read access to the file.
114 * @see java.io.File#getPath()
115 * @see java.lang.SecurityManager#checkRead(java.lang.String)
116 */
117 public FileInputStream(File file) throws FileNotFoundException {
118 String name = (file != null ? file.getPath() : null);
119 SecurityManager security = System.getSecurityManager();
120 if (security != null) {
121 security.checkRead(name);
122 }
123 if (name == null) {
124 throw new NullPointerException();
125 }
126 fd = new FileDescriptor();
127 fd.attach(this);
128 open(name);
129 }
130
131 /**
132 * Creates a <code>FileInputStream</code> by using the file descriptor
133 * <code>fdObj</code>, which represents an existing connection to an
134 * actual file in the file system.
135 * <p>
136 * If there is a security manager, its <code>checkRead</code> method is
137 * called with the file descriptor <code>fdObj</code> as its argument to
138 * see if it's ok to read the file descriptor. If read access is denied
139 * to the file descriptor a <code>SecurityException</code> is thrown.
140 * <p>
141 * If <code>fdObj</code> is null then a <code>NullPointerException</code>
142 * is thrown.
143 * <p>
144 * This constructor does not throw an exception if <code>fdObj</code>
145 * is {@link java.io.FileDescriptor#valid() invalid}.
146 * However, if the methods are invoked on the resulting stream to attempt
147 * I/O on the stream, an <code>IOException</code> is thrown.
148 *
149 * @param fdObj the file descriptor to be opened for reading.
150 * @throws SecurityException if a security manager exists and its
151 * <code>checkRead</code> method denies read access to the
152 * file descriptor.
153 * @see SecurityManager#checkRead(java.io.FileDescriptor)
154 */
155 public FileInputStream(FileDescriptor fdObj) {
156 SecurityManager security = System.getSecurityManager();
157 if (fdObj == null) {
158 throw new NullPointerException();
159 }
160 if (security != null) {
161 security.checkRead(fdObj);
162 }
163 fd = fdObj;
164
165 /*
166 * FileDescriptor is being shared by streams.
167 * Register this stream with FileDescriptor tracker.
168 */
169 fd.attach(this);
170 }
171
172 /**
173 * Opens the specified file for reading.
174 * @param name the name of the file
175 */
176 private native void open(String name) throws FileNotFoundException;
177
178 /**
179 * Reads a byte of data from this input stream. This method blocks
180 * if no input is yet available.
181 *
182 * @return the next byte of data, or <code>-1</code> if the end of the
183 * file is reached.
184 * @exception IOException if an I/O error occurs.
185 */
186 public native int read() throws IOException;
187
188 /**
189 * Reads a subarray as a sequence of bytes.
276 /**
277 * Closes this file input stream and releases any system resources
278 * associated with the stream.
279 *
280 * <p> If this stream has an associated channel then the channel is closed
281 * as well.
282 *
283 * @exception IOException if an I/O error occurs.
284 *
285 * @revised 1.4
286 * @spec JSR-51
287 */
288 public void close() throws IOException {
289 synchronized (closeLock) {
290 if (closed) {
291 return;
292 }
293 closed = true;
294 }
295 if (channel != null) {
296 channel.close();
297 }
298
299 fd.closeAll(new Closeable() {
300 public void close() throws IOException {
301 close0();
302 }
303 });
304 }
305
306 /**
307 * Returns the <code>FileDescriptor</code>
308 * object that represents the connection to
309 * the actual file in the file system being
310 * used by this <code>FileInputStream</code>.
311 *
312 * @return the file descriptor object associated with this stream.
313 * @exception IOException if an I/O error occurs.
314 * @see java.io.FileDescriptor
315 */
316 public final FileDescriptor getFD() throws IOException {
317 if (fd != null) {
318 return fd;
319 }
320 throw new IOException();
321 }
322
323 /**
324 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
325 * object associated with this file input stream.
326 *
327 * <p> The initial {@link java.nio.channels.FileChannel#position()
328 * </code>position<code>} of the returned channel will be equal to the
329 * number of bytes read from the file so far. Reading bytes from this
330 * stream will increment the channel's position. Changing the channel's
331 * position, either explicitly or by reading, will change this stream's
332 * file position.
333 *
334 * @return the file channel associated with this file input stream
335 *
336 * @since 1.4
337 * @spec JSR-51
338 */
339 public FileChannel getChannel() {
340 synchronized (this) {
341 if (channel == null) {
342 channel = FileChannelImpl.open(fd, true, false, this);
343 }
344 return channel;
345 }
346 }
347
348 private static native void initIDs();
349
350 private native void close0() throws IOException;
351
352 static {
353 initIDs();
354 }
355
356 /**
357 * Ensures that the <code>close</code> method of this file input stream is
358 * called when there are no more references to it.
359 *
360 * @exception IOException if an I/O error occurs.
361 * @see java.io.FileInputStream#close()
362 */
363 protected void finalize() throws IOException {
364 if ((fd != null) && (fd != FileDescriptor.in)) {
365 /* if fd is shared, the references in FileDescriptor
366 * will ensure that finalizer is only called when
367 * safe to do so. All references using the fd have
368 * become unreachable. We can call close()
369 */
370 close();
371 }
372 }
373 }
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