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| 1 | /* | ||
| 2 | * Copyright (c) 2000, 2009, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 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.nio.channels; | ||
| 27 | |||
| 28 | import java.io.FileInputStream; | ||
| 29 | import java.io.FileOutputStream; | ||
| 30 | import java.io.InputStream; | ||
| 31 | import java.io.OutputStream; | ||
| 32 | import java.io.Reader; | ||
| 33 | import java.io.Writer; | ||
| 34 | import java.io.IOException; | ||
| 35 | import java.nio.ByteBuffer; | ||
| 36 | import java.nio.charset.Charset; | ||
| 37 | import java.nio.charset.CharsetDecoder; | ||
| 38 | import java.nio.charset.CharsetEncoder; | ||
| 39 | import java.nio.charset.UnsupportedCharsetException; | ||
| 40 | import java.nio.channels.spi.AbstractInterruptibleChannel; | ||
| 41 | import java.util.concurrent.ExecutionException; | ||
| 42 | import sun.nio.ch.ChannelInputStream; | ||
| 43 | import sun.nio.cs.StreamDecoder; | ||
| 44 | import sun.nio.cs.StreamEncoder; | ||
| 45 | |||
| 46 | |||
| 47 | /** | ||
| 48 | * Utility methods for channels and streams. | ||
| 49 | * | ||
| 50 | * <p> This class defines static methods that support the interoperation of the | ||
| 51 | * stream classes of the <tt>{@link java.io}</tt> package with the channel | ||
| 52 | * classes of this package. </p> | ||
| 53 | * | ||
| 54 | * | ||
| 55 | * @author Mark Reinhold | ||
| 56 | * @author Mike McCloskey | ||
| 57 | * @author JSR-51 Expert Group | ||
| 58 | * @since 1.4 | ||
| 59 | */ | ||
| 60 | |||
| 61 | public final class Channels { | ||
| 62 | |||
| 63 | private Channels() { } // No instantiation | ||
| 64 | |||
| 65 | private static void checkNotNull(Object o, String name) { | ||
| 66 | if (o == null) | ||
| 67 | throw new NullPointerException("\"" + name + "\" is null!"); | ||
| 68 | } | ||
| 69 | |||
| 70 | /** | ||
| 71 | * Write all remaining bytes in buffer to the given channel. | ||
| 72 | * If the channel is selectable then it must be configured blocking. | ||
| 73 | */ | ||
| 74 | private static void writeFullyImpl(WritableByteChannel ch, ByteBuffer bb) | ||
| 75 | throws IOException | ||
| 76 | { | ||
| 77 | while (bb.remaining() > 0) { | ||
| 78 | int n = ch.write(bb); | ||
| 79 | if (n <= 0) | ||
| 80 | throw new RuntimeException("no bytes written"); | ||
| 81 | } | ||
| 82 | } | ||
| 83 | |||
| 84 | /** | ||
| 85 | * Write all remaining bytes in buffer to the given channel. | ||
| 86 | * | ||
| 87 | * @throws IllegalBlockingException | ||
| 88 | * If the channel is selectable and configured non-blocking. | ||
| 89 | */ | ||
| 90 | private static void writeFully(WritableByteChannel ch, ByteBuffer bb) | ||
| 91 | throws IOException | ||
| 92 | { | ||
| 93 | if (ch instanceof SelectableChannel) { | ||
| 94 | SelectableChannel sc = (SelectableChannel)ch; | ||
| 95 | synchronized (sc.blockingLock()) { | ||
| 96 | if (!sc.isBlocking()) | ||
| 97 | throw new IllegalBlockingModeException(); | ||
| 98 | writeFullyImpl(ch, bb); | ||
| 99 | } | ||
| 100 | } else { | ||
| 101 | writeFullyImpl(ch, bb); | ||
| 102 | } | ||
| 103 | } | ||
| 104 | |||
| 105 | // -- Byte streams from channels -- | ||
| 106 | |||
| 107 | /** | ||
| 108 | * Constructs a stream that reads bytes from the given channel. | ||
| 109 | * | ||
| 110 | * <p> The <tt>read</tt> methods of the resulting stream will throw an | ||
| 111 | * {@link IllegalBlockingModeException} if invoked while the underlying | ||
| 112 | * channel is in non-blocking mode. The stream will not be buffered, and | ||
| 113 | * it will not support the {@link InputStream#mark mark} or {@link | ||
| 114 | * InputStream#reset reset} methods. The stream will be safe for access by | ||
| 115 | * multiple concurrent threads. Closing the stream will in turn cause the | ||
| 116 | * channel to be closed. </p> | ||
| 117 | * | ||
| 118 | * @param ch | ||
| 119 | * The channel from which bytes will be read | ||
| 120 | * | ||
| 121 | * @return A new input stream | ||
| 122 | */ | ||
| 123 | public static InputStream newInputStream(ReadableByteChannel ch) { | ||
| 124 | checkNotNull(ch, "ch"); | ||
| 125 | return new sun.nio.ch.ChannelInputStream(ch); | ||
| 126 | } | ||
| 127 | |||
| 128 | /** | ||
| 129 | * Constructs a stream that writes bytes to the given channel. | ||
| 130 | * | ||
| 131 | * <p> The <tt>write</tt> methods of the resulting stream will throw an | ||
| 132 | * {@link IllegalBlockingModeException} if invoked while the underlying | ||
| 133 | * channel is in non-blocking mode. The stream will not be buffered. The | ||
| 134 | * stream will be safe for access by multiple concurrent threads. Closing | ||
| 135 | * the stream will in turn cause the channel to be closed. </p> | ||
| 136 | * | ||
| 137 | * @param ch | ||
| 138 | * The channel to which bytes will be written | ||
| 139 | * | ||
| 140 | * @return A new output stream | ||
| 141 | */ | ||
| 142 | public static OutputStream newOutputStream(final WritableByteChannel ch) { | ||
| 143 | checkNotNull(ch, "ch"); | ||
| 144 | |||
| 145 | return new OutputStream() { | ||
| 146 | |||
| 147 | private ByteBuffer bb = null; | ||
| 148 | private byte[] bs = null; // Invoker's previous array | ||
| 149 | private byte[] b1 = null; | ||
| 150 | |||
| 151 | public synchronized void write(int b) throws IOException { | ||
| 152 | if (b1 == null) | ||
| 153 | b1 = new byte[1]; | ||
| 154 | b1[0] = (byte)b; | ||
| 155 | this.write(b1); | ||
| 156 | } | ||
| 157 | |||
| 158 | public synchronized void write(byte[] bs, int off, int len) | ||
| 159 | throws IOException | ||
| 160 | { | ||
| 161 | if ((off < 0) || (off > bs.length) || (len < 0) || | ||
| 162 | ((off + len) > bs.length) || ((off + len) < 0)) { | ||
| 163 | throw new IndexOutOfBoundsException(); | ||
| 164 | } else if (len == 0) { | ||
| 165 | return; | ||
| 166 | } | ||
| 167 | ByteBuffer bb = ((this.bs == bs) | ||
| 168 | ? this.bb | ||
| 169 | : ByteBuffer.wrap(bs)); | ||
| 170 | bb.limit(Math.min(off + len, bb.capacity())); | ||
| 171 | bb.position(off); | ||
| 172 | this.bb = bb; | ||
| 173 | this.bs = bs; | ||
| 174 | Channels.writeFully(ch, bb); | ||
| 175 | } | ||
| 176 | |||
| 177 | public void close() throws IOException { | ||
| 178 | ch.close(); | ||
| 179 | } | ||
| 180 | |||
| 181 | }; | ||
| 182 | } | ||
| 183 | |||
| 184 | /** | ||
| 185 | * Constructs a stream that reads bytes from the given channel. | ||
| 186 | * | ||
| 187 | * <p> The stream will not be buffered, and it will not support the {@link | ||
| 188 | * InputStream#mark mark} or {@link InputStream#reset reset} methods. The | ||
| 189 | * stream will be safe for access by multiple concurrent threads. Closing | ||
| 190 | * the stream will in turn cause the channel to be closed. </p> | ||
| 191 | * | ||
| 192 | * @param ch | ||
| 193 | * The channel from which bytes will be read | ||
| 194 | * | ||
| 195 | * @return A new input stream | ||
| 196 | * | ||
| 197 | * @since 1.7 | ||
| 198 | */ | ||
| 199 | public static InputStream newInputStream(final AsynchronousByteChannel ch) { | ||
| 200 | checkNotNull(ch, "ch"); | ||
| 201 | return new InputStream() { | ||
| 202 | |||
| 203 | private ByteBuffer bb = null; | ||
| 204 | private byte[] bs = null; // Invoker's previous array | ||
| 205 | private byte[] b1 = null; | ||
| 206 | |||
| 207 | @Override | ||
| 208 | public synchronized int read() throws IOException { | ||
| 209 | if (b1 == null) | ||
| 210 | b1 = new byte[1]; | ||
| 211 | int n = this.read(b1); | ||
| 212 | if (n == 1) | ||
| 213 | return b1[0] & 0xff; | ||
| 214 | return -1; | ||
| 215 | } | ||
| 216 | |||
| 217 | @Override | ||
| 218 | public synchronized int read(byte[] bs, int off, int len) | ||
| 219 | throws IOException | ||
| 220 | { | ||
| 221 | if ((off < 0) || (off > bs.length) || (len < 0) || | ||
| 222 | ((off + len) > bs.length) || ((off + len) < 0)) { | ||
| 223 | throw new IndexOutOfBoundsException(); | ||
| 224 | } else if (len == 0) | ||
| 225 | return 0; | ||
| 226 | |||
| 227 | ByteBuffer bb = ((this.bs == bs) | ||
| 228 | ? this.bb | ||
| 229 | : ByteBuffer.wrap(bs)); | ||
| 230 | bb.position(off); | ||
| 231 | bb.limit(Math.min(off + len, bb.capacity())); | ||
| 232 | this.bb = bb; | ||
| 233 | this.bs = bs; | ||
| 234 | |||
| 235 | boolean interrupted = false; | ||
| 236 | try { | ||
| 237 | for (;;) { | ||
| 238 | try { | ||
| 239 | return ch.read(bb).get(); | ||
| 240 | } catch (ExecutionException ee) { | ||
| 241 | throw new IOException(ee.getCause()); | ||
| 242 | } catch (InterruptedException ie) { | ||
| 243 | interrupted = true; | ||
| 244 | } | ||
| 245 | } | ||
| 246 | } finally { | ||
| 247 | if (interrupted) | ||
| 248 | Thread.currentThread().interrupt(); | ||
| 249 | } | ||
| 250 | } | ||
| 251 | |||
| 252 | @Override | ||
| 253 | public void close() throws IOException { | ||
| 254 | ch.close(); | ||
| 255 | } | ||
| 256 | }; | ||
| 257 | } | ||
| 258 | |||
| 259 | /** | ||
| 260 | * Constructs a stream that writes bytes to the given channel. | ||
| 261 | * | ||
| 262 | * <p> The stream will not be buffered. The stream will be safe for access | ||
| 263 | * by multiple concurrent threads. Closing the stream will in turn cause | ||
| 264 | * the channel to be closed. </p> | ||
| 265 | * | ||
| 266 | * @param ch | ||
| 267 | * The channel to which bytes will be written | ||
| 268 | * | ||
| 269 | * @return A new output stream | ||
| 270 | * | ||
| 271 | * @since 1.7 | ||
| 272 | */ | ||
| 273 | public static OutputStream newOutputStream(final AsynchronousByteChannel ch) { | ||
| 274 | checkNotNull(ch, "ch"); | ||
| 275 | return new OutputStream() { | ||
| 276 | |||
| 277 | private ByteBuffer bb = null; | ||
| 278 | private byte[] bs = null; // Invoker's previous array | ||
| 279 | private byte[] b1 = null; | ||
| 280 | |||
| 281 | @Override | ||
| 282 | public synchronized void write(int b) throws IOException { | ||
| 283 | if (b1 == null) | ||
| 284 | b1 = new byte[1]; | ||
| 285 | b1[0] = (byte)b; | ||
| 286 | this.write(b1); | ||
| 287 | } | ||
| 288 | |||
| 289 | @Override | ||
| 290 | public synchronized void write(byte[] bs, int off, int len) | ||
| 291 | throws IOException | ||
| 292 | { | ||
| 293 | if ((off < 0) || (off > bs.length) || (len < 0) || | ||
| 294 | ((off + len) > bs.length) || ((off + len) < 0)) { | ||
| 295 | throw new IndexOutOfBoundsException(); | ||
| 296 | } else if (len == 0) { | ||
| 297 | return; | ||
| 298 | } | ||
| 299 | ByteBuffer bb = ((this.bs == bs) | ||
| 300 | ? this.bb | ||
| 301 | : ByteBuffer.wrap(bs)); | ||
| 302 | bb.limit(Math.min(off + len, bb.capacity())); | ||
| 303 | bb.position(off); | ||
| 304 | this.bb = bb; | ||
| 305 | this.bs = bs; | ||
| 306 | |||
| 307 | boolean interrupted = false; | ||
| 308 | try { | ||
| 309 | while (bb.remaining() > 0) { | ||
| 310 | try { | ||
| 311 | ch.write(bb).get(); | ||
| 312 | } catch (ExecutionException ee) { | ||
| 313 | throw new IOException(ee.getCause()); | ||
| 314 | } catch (InterruptedException ie) { | ||
| 315 | interrupted = true; | ||
| 316 | } | ||
| 317 | } | ||
| 318 | } finally { | ||
| 319 | if (interrupted) | ||
| 320 | Thread.currentThread().interrupt(); | ||
| 321 | } | ||
| 322 | } | ||
| 323 | |||
| 324 | @Override | ||
| 325 | public void close() throws IOException { | ||
| 326 | ch.close(); | ||
| 327 | } | ||
| 328 | }; | ||
| 329 | } | ||
| 330 | |||
| 331 | |||
| 332 | // -- Channels from streams -- | ||
| 333 | |||
| 334 | /** | ||
| 335 | * Constructs a channel that reads bytes from the given stream. | ||
| 336 | * | ||
| 337 | * <p> The resulting channel will not be buffered; it will simply redirect | ||
| 338 | * its I/O operations to the given stream. Closing the channel will in | ||
| 339 | * turn cause the stream to be closed. </p> | ||
| 340 | * | ||
| 341 | * @param in | ||
| 342 | * The stream from which bytes are to be read | ||
| 343 | * | ||
| 344 | * @return A new readable byte channel | ||
| 345 | */ | ||
| 346 | public static ReadableByteChannel newChannel(final InputStream in) { | ||
| 347 | checkNotNull(in, "in"); | ||
| 348 | |||
| 349 | if (in instanceof FileInputStream && | ||
| 350 | FileInputStream.class.equals(in.getClass())) { | ||
| 351 | return ((FileInputStream)in).getChannel(); | ||
| 352 | } | ||
| 353 | |||
| 354 | return new ReadableByteChannelImpl(in); | ||
| 355 | } | ||
| 356 | |||
| 357 | private static class ReadableByteChannelImpl | ||
| 358 | extends AbstractInterruptibleChannel // Not really interruptible | ||
| 359 | implements ReadableByteChannel | ||
| 360 | { | ||
| 361 | InputStream in; | ||
| 362 | private static final int TRANSFER_SIZE = 8192; | ||
| 363 | private byte buf[] = new byte[0]; | ||
| 364 | private boolean open = true; | ||
| 365 | private Object readLock = new Object(); | ||
| 366 | |||
| 367 | ReadableByteChannelImpl(InputStream in) { | ||
| 368 | this.in = in; | ||
| 369 | } | ||
| 370 | |||
| 371 | public int read(ByteBuffer dst) throws IOException { | ||
| 372 | int len = dst.remaining(); | ||
| 373 | int totalRead = 0; | ||
| 374 | int bytesRead = 0; | ||
| 375 | synchronized (readLock) { | ||
| 376 | while (totalRead < len) { | ||
| 377 | int bytesToRead = Math.min((len - totalRead), | ||
| 378 | TRANSFER_SIZE); | ||
| 379 | if (buf.length < bytesToRead) | ||
| 380 | buf = new byte[bytesToRead]; | ||
| 381 | if ((totalRead > 0) && !(in.available() > 0)) | ||
| 382 | break; // block at most once | ||
| 383 | try { | ||
| 384 | begin(); | ||
| 385 | bytesRead = in.read(buf, 0, bytesToRead); | ||
| 386 | } finally { | ||
| 387 | end(bytesRead > 0); | ||
| 388 | } | ||
| 389 | if (bytesRead < 0) | ||
| 390 | break; | ||
| 391 | else | ||
| 392 | totalRead += bytesRead; | ||
| 393 | dst.put(buf, 0, bytesRead); | ||
| 394 | } | ||
| 395 | if ((bytesRead < 0) && (totalRead == 0)) | ||
| 396 | return -1; | ||
| 397 | |||
| 398 | return totalRead; | ||
| 399 | } | ||
| 400 | } | ||
| 401 | |||
| 402 | protected void implCloseChannel() throws IOException { | ||
| 403 | in.close(); | ||
| 404 | open = false; | ||
| 405 | } | ||
| 406 | } | ||
| 407 | |||
| 408 | |||
| 409 | /** | ||
| 410 | * Constructs a channel that writes bytes to the given stream. | ||
| 411 | * | ||
| 412 | * <p> The resulting channel will not be buffered; it will simply redirect | ||
| 413 | * its I/O operations to the given stream. Closing the channel will in | ||
| 414 | * turn cause the stream to be closed. </p> | ||
| 415 | * | ||
| 416 | * @param out | ||
| 417 | * The stream to which bytes are to be written | ||
| 418 | * | ||
| 419 | * @return A new writable byte channel | ||
| 420 | */ | ||
| 421 | public static WritableByteChannel newChannel(final OutputStream out) { | ||
| 422 | checkNotNull(out, "out"); | ||
| 423 | |||
| 424 | if (out instanceof FileOutputStream && | ||
| 425 | FileOutputStream.class.equals(out.getClass())) { | ||
| 426 | return ((FileOutputStream)out).getChannel(); | ||
| 427 | } | ||
| 428 | |||
| 429 | return new WritableByteChannelImpl(out); | ||
| 430 | } | ||
| 431 | |||
| 432 | private static class WritableByteChannelImpl | ||
| 433 | extends AbstractInterruptibleChannel // Not really interruptible | ||
| 434 | implements WritableByteChannel | ||
| 435 | { | ||
| 436 | OutputStream out; | ||
| 437 | private static final int TRANSFER_SIZE = 8192; | ||
| 438 | private byte buf[] = new byte[0]; | ||
| 439 | private boolean open = true; | ||
| 440 | private Object writeLock = new Object(); | ||
| 441 | |||
| 442 | WritableByteChannelImpl(OutputStream out) { | ||
| 443 | this.out = out; | ||
| 444 | } | ||
| 445 | |||
| 446 | public int write(ByteBuffer src) throws IOException { | ||
| 447 | int len = src.remaining(); | ||
| 448 | int totalWritten = 0; | ||
| 449 | synchronized (writeLock) { | ||
| 450 | while (totalWritten < len) { | ||
| 451 | int bytesToWrite = Math.min((len - totalWritten), | ||
| 452 | TRANSFER_SIZE); | ||
| 453 | if (buf.length < bytesToWrite) | ||
| 454 | buf = new byte[bytesToWrite]; | ||
| 455 | src.get(buf, 0, bytesToWrite); | ||
| 456 | try { | ||
| 457 | begin(); | ||
| 458 | out.write(buf, 0, bytesToWrite); | ||
| 459 | } finally { | ||
| 460 | end(bytesToWrite > 0); | ||
| 461 | } | ||
| 462 | totalWritten += bytesToWrite; | ||
| 463 | } | ||
| 464 | return totalWritten; | ||
| 465 | } | ||
| 466 | } | ||
| 467 | |||
| 468 | protected void implCloseChannel() throws IOException { | ||
| 469 | out.close(); | ||
| 470 | open = false; | ||
| 471 | } | ||
| 472 | } | ||
| 473 | |||
| 474 | |||
| 475 | // -- Character streams from channels -- | ||
| 476 | |||
| 477 | /** | ||
| 478 | * Constructs a reader that decodes bytes from the given channel using the | ||
| 479 | * given decoder. | ||
| 480 | * | ||
| 481 | * <p> The resulting stream will contain an internal input buffer of at | ||
| 482 | * least <tt>minBufferCap</tt> bytes. The stream's <tt>read</tt> methods | ||
| 483 | * will, as needed, fill the buffer by reading bytes from the underlying | ||
| 484 | * channel; if the channel is in non-blocking mode when bytes are to be | ||
| 485 | * read then an {@link IllegalBlockingModeException} will be thrown. The | ||
| 486 | * resulting stream will not otherwise be buffered, and it will not support | ||
| 487 | * the {@link Reader#mark mark} or {@link Reader#reset reset} methods. | ||
| 488 | * Closing the stream will in turn cause the channel to be closed. </p> | ||
| 489 | * | ||
| 490 | * @param ch | ||
| 491 | * The channel from which bytes will be read | ||
| 492 | * | ||
| 493 | * @param dec | ||
| 494 | * The charset decoder to be used | ||
| 495 | * | ||
| 496 | * @param minBufferCap | ||
| 497 | * The minimum capacity of the internal byte buffer, | ||
| 498 | * or <tt>-1</tt> if an implementation-dependent | ||
| 499 | * default capacity is to be used | ||
| 500 | * | ||
| 501 | * @return A new reader | ||
| 502 | */ | ||
| 503 | public static Reader newReader(ReadableByteChannel ch, | ||
| 504 | CharsetDecoder dec, | ||
| 505 | int minBufferCap) | ||
| 506 | { | ||
| 507 | checkNotNull(ch, "ch"); | ||
| 508 | return StreamDecoder.forDecoder(ch, dec.reset(), minBufferCap); | ||
| 509 | } | ||
| 510 | |||
| 511 | /** | ||
| 512 | * Constructs a reader that decodes bytes from the given channel according | ||
| 513 | * to the named charset. | ||
| 514 | * | ||
| 515 | * <p> An invocation of this method of the form | ||
| 516 | * | ||
| 517 | * <blockquote><pre> | ||
| 518 | * Channels.newReader(ch, csname)</pre></blockquote> | ||
| 519 | * | ||
| 520 | * behaves in exactly the same way as the expression | ||
| 521 | * | ||
| 522 | * <blockquote><pre> | ||
| 523 | * Channels.newReader(ch, | ||
| 524 | * Charset.forName(csName) | ||
| 525 | * .newDecoder(), | ||
| 526 | * -1);</pre></blockquote> | ||
| 527 | * | ||
| 528 | * @param ch | ||
| 529 | * The channel from which bytes will be read | ||
| 530 | * | ||
| 531 | * @param csName | ||
| 532 | * The name of the charset to be used | ||
| 533 | * | ||
| 534 | * @return A new reader | ||
| 535 | * | ||
| 536 | * @throws UnsupportedCharsetException | ||
| 537 | * If no support for the named charset is available | ||
| 538 | * in this instance of the Java virtual machine | ||
| 539 | */ | ||
| 540 | public static Reader newReader(ReadableByteChannel ch, | ||
| 541 | String csName) | ||
| 542 | { | ||
| 543 | checkNotNull(csName, "csName"); | ||
| 544 | return newReader(ch, Charset.forName(csName).newDecoder(), -1); | ||
| 545 | } | ||
| 546 | |||
| 547 | /** | ||
| 548 | * Constructs a writer that encodes characters using the given encoder and | ||
| 549 | * writes the resulting bytes to the given channel. | ||
| 550 | * | ||
| 551 | * <p> The resulting stream will contain an internal output buffer of at | ||
| 552 | * least <tt>minBufferCap</tt> bytes. The stream's <tt>write</tt> methods | ||
| 553 | * will, as needed, flush the buffer by writing bytes to the underlying | ||
| 554 | * channel; if the channel is in non-blocking mode when bytes are to be | ||
| 555 | * written then an {@link IllegalBlockingModeException} will be thrown. | ||
| 556 | * The resulting stream will not otherwise be buffered. Closing the stream | ||
| 557 | * will in turn cause the channel to be closed. </p> | ||
| 558 | * | ||
| 559 | * @param ch | ||
| 560 | * The channel to which bytes will be written | ||
| 561 | * | ||
| 562 | * @param enc | ||
| 563 | * The charset encoder to be used | ||
| 564 | * | ||
| 565 | * @param minBufferCap | ||
| 566 | * The minimum capacity of the internal byte buffer, | ||
| 567 | * or <tt>-1</tt> if an implementation-dependent | ||
| 568 | * default capacity is to be used | ||
| 569 | * | ||
| 570 | * @return A new writer | ||
| 571 | */ | ||
| 572 | public static Writer newWriter(final WritableByteChannel ch, | ||
| 573 | final CharsetEncoder enc, | ||
| 574 | final int minBufferCap) | ||
| 575 | { | ||
| 576 | checkNotNull(ch, "ch"); | ||
| 577 | return StreamEncoder.forEncoder(ch, enc.reset(), minBufferCap); | ||
| 578 | } | ||
| 579 | |||
| 580 | /** | ||
| 581 | * Constructs a writer that encodes characters according to the named | ||
| 582 | * charset and writes the resulting bytes to the given channel. | ||
| 583 | * | ||
| 584 | * <p> An invocation of this method of the form | ||
| 585 | * | ||
| 586 | * <blockquote><pre> | ||
| 587 | * Channels.newWriter(ch, csname)</pre></blockquote> | ||
| 588 | * | ||
| 589 | * behaves in exactly the same way as the expression | ||
| 590 | * | ||
| 591 | * <blockquote><pre> | ||
| 592 | * Channels.newWriter(ch, | ||
| 593 | * Charset.forName(csName) | ||
| 594 | * .newEncoder(), | ||
| 595 | * -1);</pre></blockquote> | ||
| 596 | * | ||
| 597 | * @param ch | ||
| 598 | * The channel to which bytes will be written | ||
| 599 | * | ||
| 600 | * @param csName | ||
| 601 | * The name of the charset to be used | ||
| 602 | * | ||
| 603 | * @return A new writer | ||
| 604 | * | ||
| 605 | * @throws UnsupportedCharsetException | ||
| 606 | * If no support for the named charset is available | ||
| 607 | * in this instance of the Java virtual machine | ||
| 608 | */ | ||
| 609 | public static Writer newWriter(WritableByteChannel ch, | ||
| 610 | String csName) | ||
| 611 | { | ||
| 612 | checkNotNull(csName, "csName"); | ||
| 613 | return newWriter(ch, Charset.forName(csName).newEncoder(), -1); | ||
| 614 | } | ||
| 615 | } | ||