231 * integrity</a>). </td>
232 * <tr>
233 * <tr>
234 * <td> {@link StandardOpenOption#DSYNC DSYNC} </td>
235 * <td> Requires that every update to the file's content be written
236 * synchronously to the underlying storage device. (see <a
237 * href="../file/package-summary.html#integrity"> Synchronized I/O file
238 * integrity</a>). </td>
239 * </tr>
240 * </table>
241 *
242 * <p> An implementation may also support additional options.
243 *
244 * <p> The {@code attrs} parameter is an optional array of file {@link
245 * FileAttribute file-attributes} to set atomically when creating the file.
246 *
247 * <p> The new channel is created by invoking the {@link
248 * FileSystemProvider#newFileChannel newFileChannel} method on the
249 * provider that created the {@code Path}.
250 *
251 * @param file
252 * The path of the file to open or create
253 * @param options
254 * Options specifying how the file is opened
255 * @param attrs
256 * An optional list of file attributes to set atomically when
257 * creating the file
258 *
259 * @return A new file channel
260 *
261 * @throws IllegalArgumentException
262 * If the set contains an invalid combination of options
263 * @throws UnsupportedOperationException
264 * If the {@code file} is associated with a provider that does not
265 * support creating file channels, or an unsupported open option is
266 * specified, or the array contains an attribute that cannot be set
267 * atomically when creating the file
268 * @throws IOException
269 * If an I/O error occurs
270 * @throws SecurityException
271 * If a security manager is installed and it denies an
272 * unspecified permission required by the implementation.
273 * In the case of the default provider, the {@link
274 * SecurityManager#checkRead(String)} method is invoked to check
275 * read access if the file is opened for reading. The {@link
276 * SecurityManager#checkWrite(String)} method is invoked to check
277 * write access if the file is opened for writing
278 *
279 * @since 1.7
280 */
281 public static FileChannel open(Path file,
282 Set<? extends OpenOption> options,
283 FileAttribute<?>... attrs)
284 throws IOException
285 {
286 FileSystemProvider provider = file.getFileSystem().provider();
287 return provider.newFileChannel(file, options, attrs);
288 }
289
290 private static final FileAttribute<?>[] NO_ATTRIBUTES = new FileAttribute[0];
291
292 /**
293 * Opens or creates a file, returning a file channel to access the file.
294 *
295 * <p> An invocation of this method behaves in exactly the same way as the
296 * invocation
297 * <pre>
298 * fc.{@link #open(Path,Set,FileAttribute[]) open}(file, options, new FileAttribute<?>[0]);
299 * </pre>
300 *
301 * @param file
302 * The path of the file to open or create
303 * @param options
304 * Options specifying how the file is opened
305 *
306 * @return A new file channel
307 *
308 * @throws IllegalArgumentException
309 * If the set contains an invalid combination of options
310 * @throws UnsupportedOperationException
311 * If the {@code file} is associated with a provider that does not
312 * support creating file channels, or an unsupported open option is
313 * specified
314 * @throws IOException
315 * If an I/O error occurs
316 * @throws SecurityException
317 * If a security manager is installed and it denies an
318 * unspecified permission required by the implementation.
319 * In the case of the default provider, the {@link
320 * SecurityManager#checkRead(String)} method is invoked to check
321 * read access if the file is opened for reading. The {@link
322 * SecurityManager#checkWrite(String)} method is invoked to check
323 * write access if the file is opened for writing
324 *
325 * @since 1.7
326 */
327 public static FileChannel open(Path file, OpenOption... options)
328 throws IOException
329 {
330 Set<OpenOption> set = new HashSet<OpenOption>(options.length);
331 Collections.addAll(set, options);
332 return open(file, set, NO_ATTRIBUTES);
333 }
334
335 // -- Channel operations --
336
337 /**
338 * Reads a sequence of bytes from this channel into the given buffer.
339 *
340 * <p> Bytes are read starting at this channel's current file position, and
341 * then the file position is updated with the number of bytes actually
342 * read. Otherwise this method behaves exactly as specified in the {@link
343 * ReadableByteChannel} interface. </p>
344 */
345 public abstract int read(ByteBuffer dst) throws IOException;
346
347 /**
348 * Reads a sequence of bytes from this channel into a subsequence of the
349 * given buffers.
350 *
351 * <p> Bytes are read starting at this channel's current file position, and
352 * then the file position is updated with the number of bytes actually
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231 * integrity</a>). </td>
232 * <tr>
233 * <tr>
234 * <td> {@link StandardOpenOption#DSYNC DSYNC} </td>
235 * <td> Requires that every update to the file's content be written
236 * synchronously to the underlying storage device. (see <a
237 * href="../file/package-summary.html#integrity"> Synchronized I/O file
238 * integrity</a>). </td>
239 * </tr>
240 * </table>
241 *
242 * <p> An implementation may also support additional options.
243 *
244 * <p> The {@code attrs} parameter is an optional array of file {@link
245 * FileAttribute file-attributes} to set atomically when creating the file.
246 *
247 * <p> The new channel is created by invoking the {@link
248 * FileSystemProvider#newFileChannel newFileChannel} method on the
249 * provider that created the {@code Path}.
250 *
251 * @param path
252 * The path of the file to open or create
253 * @param options
254 * Options specifying how the file is opened
255 * @param attrs
256 * An optional list of file attributes to set atomically when
257 * creating the file
258 *
259 * @return A new file channel
260 *
261 * @throws IllegalArgumentException
262 * If the set contains an invalid combination of options
263 * @throws UnsupportedOperationException
264 * If the {@code path} is associated with a provider that does not
265 * support creating file channels, or an unsupported open option is
266 * specified, or the array contains an attribute that cannot be set
267 * atomically when creating the file
268 * @throws IOException
269 * If an I/O error occurs
270 * @throws SecurityException
271 * If a security manager is installed and it denies an
272 * unspecified permission required by the implementation.
273 * In the case of the default provider, the {@link
274 * SecurityManager#checkRead(String)} method is invoked to check
275 * read access if the file is opened for reading. The {@link
276 * SecurityManager#checkWrite(String)} method is invoked to check
277 * write access if the file is opened for writing
278 *
279 * @since 1.7
280 */
281 public static FileChannel open(Path path,
282 Set<? extends OpenOption> options,
283 FileAttribute<?>... attrs)
284 throws IOException
285 {
286 FileSystemProvider provider = path.getFileSystem().provider();
287 return provider.newFileChannel(path, options, attrs);
288 }
289
290 private static final FileAttribute<?>[] NO_ATTRIBUTES = new FileAttribute[0];
291
292 /**
293 * Opens or creates a file, returning a file channel to access the file.
294 *
295 * <p> An invocation of this method behaves in exactly the same way as the
296 * invocation
297 * <pre>
298 * fc.{@link #open(Path,Set,FileAttribute[]) open}(file, opts, new FileAttribute<?>[0]);
299 * </pre>
300 * where {@code opts} is a set of the options specified in the {@code
301 * options} array.
302 *
303 * @param path
304 * The path of the file to open or create
305 * @param options
306 * Options specifying how the file is opened
307 *
308 * @return A new file channel
309 *
310 * @throws IllegalArgumentException
311 * If the set contains an invalid combination of options
312 * @throws UnsupportedOperationException
313 * If the {@code path} is associated with a provider that does not
314 * support creating file channels, or an unsupported open option is
315 * specified
316 * @throws IOException
317 * If an I/O error occurs
318 * @throws SecurityException
319 * If a security manager is installed and it denies an
320 * unspecified permission required by the implementation.
321 * In the case of the default provider, the {@link
322 * SecurityManager#checkRead(String)} method is invoked to check
323 * read access if the file is opened for reading. The {@link
324 * SecurityManager#checkWrite(String)} method is invoked to check
325 * write access if the file is opened for writing
326 *
327 * @since 1.7
328 */
329 public static FileChannel open(Path path, OpenOption... options)
330 throws IOException
331 {
332 Set<OpenOption> set = new HashSet<OpenOption>(options.length);
333 Collections.addAll(set, options);
334 return open(path, set, NO_ATTRIBUTES);
335 }
336
337 // -- Channel operations --
338
339 /**
340 * Reads a sequence of bytes from this channel into the given buffer.
341 *
342 * <p> Bytes are read starting at this channel's current file position, and
343 * then the file position is updated with the number of bytes actually
344 * read. Otherwise this method behaves exactly as specified in the {@link
345 * ReadableByteChannel} interface. </p>
346 */
347 public abstract int read(ByteBuffer dst) throws IOException;
348
349 /**
350 * Reads a sequence of bytes from this channel into a subsequence of the
351 * given buffers.
352 *
353 * <p> Bytes are read starting at this channel's current file position, and
354 * then the file position is updated with the number of bytes actually
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