1 /* 2 * Copyright (c) 1994, 2018, 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.io; 27 28 import java.util.ArrayList; 29 import java.util.Arrays; 30 import java.util.List; 31 import java.util.Objects; 32 33 /** 34 * This abstract class is the superclass of all classes representing 35 * an input stream of bytes. 36 * 37 * <p> Applications that need to define a subclass of <code>InputStream</code> 38 * must always provide a method that returns the next byte of input. 39 * 40 * @author Arthur van Hoff 41 * @see java.io.BufferedInputStream 42 * @see java.io.ByteArrayInputStream 43 * @see java.io.DataInputStream 44 * @see java.io.FilterInputStream 45 * @see java.io.InputStream#read() 46 * @see java.io.OutputStream 47 * @see java.io.PushbackInputStream 48 * @since 1.0 49 */ 50 public abstract class InputStream implements Closeable { 51 52 // MAX_SKIP_BUFFER_SIZE is used to determine the maximum buffer size to 53 // use when skipping. 54 private static final int MAX_SKIP_BUFFER_SIZE = 2048; 55 56 private static final int DEFAULT_BUFFER_SIZE = 8192; 57 58 /** 59 * Returns a new {@code InputStream} that reads no bytes. The returned 60 * stream is initially open. The stream is closed by calling the 61 * {@code close()} method. Subsequent calls to {@code close()} have no 62 * effect. 63 * 64 * <p> While the stream is open, the {@code available()}, {@code read()}, 65 * {@code read(byte[])}, {@code read(byte[], int, int)}, 66 * {@code readAllBytes()}, {@code readNBytes(byte[], int, int)}, 67 * {@code readNBytes(int)}, {@code skip(long)}, and 68 * {@code transferTo()} methods all behave as if end of stream has been 69 * reached. After the stream has been closed, these methods all throw 70 * {@code IOException}. 71 * 72 * <p> The {@code markSupported()} method returns {@code false}. The 73 * {@code mark()} method does nothing, and the {@code reset()} method 74 * throws {@code IOException}. 75 * 76 * @return an {@code InputStream} which contains no bytes 77 * 78 * @since 11 79 */ nullInputStream()80 public static InputStream nullInputStream() { 81 return new InputStream() { 82 private volatile boolean closed; 83 84 private void ensureOpen() throws IOException { 85 if (closed) { 86 throw new IOException("Stream closed"); 87 } 88 } 89 90 @Override 91 public int available () throws IOException { 92 ensureOpen(); 93 return 0; 94 } 95 96 @Override 97 public int read() throws IOException { 98 ensureOpen(); 99 return -1; 100 } 101 102 @Override 103 public int read(byte[] b, int off, int len) throws IOException { 104 Objects.checkFromIndexSize(off, len, b.length); 105 if (len == 0) { 106 return 0; 107 } 108 ensureOpen(); 109 return -1; 110 } 111 112 @Override 113 public byte[] readAllBytes() throws IOException { 114 ensureOpen(); 115 return new byte[0]; 116 } 117 118 @Override 119 public int readNBytes(byte[] b, int off, int len) 120 throws IOException { 121 Objects.checkFromIndexSize(off, len, b.length); 122 ensureOpen(); 123 return 0; 124 } 125 126 @Override 127 public byte[] readNBytes(int len) throws IOException { 128 if (len < 0) { 129 throw new IllegalArgumentException("len < 0"); 130 } 131 ensureOpen(); 132 return new byte[0]; 133 } 134 135 @Override 136 public long skip(long n) throws IOException { 137 ensureOpen(); 138 return 0L; 139 } 140 141 @Override 142 public long transferTo(OutputStream out) throws IOException { 143 Objects.requireNonNull(out); 144 ensureOpen(); 145 return 0L; 146 } 147 148 @Override 149 public void close() throws IOException { 150 closed = true; 151 } 152 }; 153 } 154 155 /** 156 * Reads the next byte of data from the input stream. The value byte is 157 * returned as an <code>int</code> in the range <code>0</code> to 158 * <code>255</code>. If no byte is available because the end of the stream 159 * has been reached, the value <code>-1</code> is returned. This method 160 * blocks until input data is available, the end of the stream is detected, 161 * or an exception is thrown. 162 * 163 * <p> A subclass must provide an implementation of this method. 164 * 165 * @return the next byte of data, or <code>-1</code> if the end of the 166 * stream is reached. 167 * @exception IOException if an I/O error occurs. 168 */ read()169 public abstract int read() throws IOException; 170 171 /** 172 * Reads some number of bytes from the input stream and stores them into 173 * the buffer array <code>b</code>. The number of bytes actually read is 174 * returned as an integer. This method blocks until input data is 175 * available, end of file is detected, or an exception is thrown. 176 * 177 * <p> If the length of <code>b</code> is zero, then no bytes are read and 178 * <code>0</code> is returned; otherwise, there is an attempt to read at 179 * least one byte. If no byte is available because the stream is at the 180 * end of the file, the value <code>-1</code> is returned; otherwise, at 181 * least one byte is read and stored into <code>b</code>. 182 * 183 * <p> The first byte read is stored into element <code>b[0]</code>, the 184 * next one into <code>b[1]</code>, and so on. The number of bytes read is, 185 * at most, equal to the length of <code>b</code>. Let <i>k</i> be the 186 * number of bytes actually read; these bytes will be stored in elements 187 * <code>b[0]</code> through <code>b[</code><i>k</i><code>-1]</code>, 188 * leaving elements <code>b[</code><i>k</i><code>]</code> through 189 * <code>b[b.length-1]</code> unaffected. 190 * 191 * <p> The <code>read(b)</code> method for class <code>InputStream</code> 192 * has the same effect as: <pre><code> read(b, 0, b.length) </code></pre> 193 * 194 * @param b the buffer into which the data is read. 195 * @return the total number of bytes read into the buffer, or 196 * <code>-1</code> if there is no more data because the end of 197 * the stream has been reached. 198 * @exception IOException If the first byte cannot be read for any reason 199 * other than the end of the file, if the input stream has been closed, or 200 * if some other I/O error occurs. 201 * @exception NullPointerException if <code>b</code> is <code>null</code>. 202 * @see java.io.InputStream#read(byte[], int, int) 203 */ read(byte b[])204 public int read(byte b[]) throws IOException { 205 return read(b, 0, b.length); 206 } 207 208 /** 209 * Reads up to <code>len</code> bytes of data from the input stream into 210 * an array of bytes. An attempt is made to read as many as 211 * <code>len</code> bytes, but a smaller number may be read. 212 * The number of bytes actually read is returned as an integer. 213 * 214 * <p> This method blocks until input data is available, end of file is 215 * detected, or an exception is thrown. 216 * 217 * <p> If <code>len</code> is zero, then no bytes are read and 218 * <code>0</code> is returned; otherwise, there is an attempt to read at 219 * least one byte. If no byte is available because the stream is at end of 220 * file, the value <code>-1</code> is returned; otherwise, at least one 221 * byte is read and stored into <code>b</code>. 222 * 223 * <p> The first byte read is stored into element <code>b[off]</code>, the 224 * next one into <code>b[off+1]</code>, and so on. The number of bytes read 225 * is, at most, equal to <code>len</code>. Let <i>k</i> be the number of 226 * bytes actually read; these bytes will be stored in elements 227 * <code>b[off]</code> through <code>b[off+</code><i>k</i><code>-1]</code>, 228 * leaving elements <code>b[off+</code><i>k</i><code>]</code> through 229 * <code>b[off+len-1]</code> unaffected. 230 * 231 * <p> In every case, elements <code>b[0]</code> through 232 * <code>b[off]</code> and elements <code>b[off+len]</code> through 233 * <code>b[b.length-1]</code> are unaffected. 234 * 235 * <p> The <code>read(b,</code> <code>off,</code> <code>len)</code> method 236 * for class <code>InputStream</code> simply calls the method 237 * <code>read()</code> repeatedly. If the first such call results in an 238 * <code>IOException</code>, that exception is returned from the call to 239 * the <code>read(b,</code> <code>off,</code> <code>len)</code> method. If 240 * any subsequent call to <code>read()</code> results in a 241 * <code>IOException</code>, the exception is caught and treated as if it 242 * were end of file; the bytes read up to that point are stored into 243 * <code>b</code> and the number of bytes read before the exception 244 * occurred is returned. The default implementation of this method blocks 245 * until the requested amount of input data <code>len</code> has been read, 246 * end of file is detected, or an exception is thrown. Subclasses are 247 * encouraged to provide a more efficient implementation of this method. 248 * 249 * @param b the buffer into which the data is read. 250 * @param off the start offset in array <code>b</code> 251 * at which the data is written. 252 * @param len the maximum number of bytes to read. 253 * @return the total number of bytes read into the buffer, or 254 * <code>-1</code> if there is no more data because the end of 255 * the stream has been reached. 256 * @exception IOException If the first byte cannot be read for any reason 257 * other than end of file, or if the input stream has been closed, or if 258 * some other I/O error occurs. 259 * @exception NullPointerException If <code>b</code> is <code>null</code>. 260 * @exception IndexOutOfBoundsException If <code>off</code> is negative, 261 * <code>len</code> is negative, or <code>len</code> is greater than 262 * <code>b.length - off</code> 263 * @see java.io.InputStream#read() 264 */ read(byte b[], int off, int len)265 public int read(byte b[], int off, int len) throws IOException { 266 Objects.checkFromIndexSize(off, len, b.length); 267 if (len == 0) { 268 return 0; 269 } 270 271 int c = read(); 272 if (c == -1) { 273 return -1; 274 } 275 b[off] = (byte)c; 276 277 int i = 1; 278 try { 279 for (; i < len ; i++) { 280 c = read(); 281 if (c == -1) { 282 break; 283 } 284 b[off + i] = (byte)c; 285 } 286 } catch (IOException ee) { 287 } 288 return i; 289 } 290 291 /** 292 * The maximum size of array to allocate. 293 * Some VMs reserve some header words in an array. 294 * Attempts to allocate larger arrays may result in 295 * OutOfMemoryError: Requested array size exceeds VM limit 296 */ 297 private static final int MAX_BUFFER_SIZE = Integer.MAX_VALUE - 8; 298 299 /** 300 * Reads all remaining bytes from the input stream. This method blocks until 301 * all remaining bytes have been read and end of stream is detected, or an 302 * exception is thrown. This method does not close the input stream. 303 * 304 * <p> When this stream reaches end of stream, further invocations of this 305 * method will return an empty byte array. 306 * 307 * <p> Note that this method is intended for simple cases where it is 308 * convenient to read all bytes into a byte array. It is not intended for 309 * reading input streams with large amounts of data. 310 * 311 * <p> The behavior for the case where the input stream is <i>asynchronously 312 * closed</i>, or the thread interrupted during the read, is highly input 313 * stream specific, and therefore not specified. 314 * 315 * <p> If an I/O error occurs reading from the input stream, then it may do 316 * so after some, but not all, bytes have been read. Consequently the input 317 * stream may not be at end of stream and may be in an inconsistent state. 318 * It is strongly recommended that the stream be promptly closed if an I/O 319 * error occurs. 320 * 321 * @implSpec 322 * This method invokes {@link #readNBytes(int)} with a length of 323 * {@link Integer#MAX_VALUE}. 324 * 325 * @return a byte array containing the bytes read from this input stream 326 * @throws IOException if an I/O error occurs 327 * @throws OutOfMemoryError if an array of the required size cannot be 328 * allocated. 329 * 330 * @since 9 331 */ readAllBytes()332 public byte[] readAllBytes() throws IOException { 333 return readNBytes(Integer.MAX_VALUE); 334 } 335 336 /** 337 * Reads up to a specified number of bytes from the input stream. This 338 * method blocks until the requested number of bytes have been read, end 339 * of stream is detected, or an exception is thrown. This method does not 340 * close the input stream. 341 * 342 * <p> The length of the returned array equals the number of bytes read 343 * from the stream. If {@code len} is zero, then no bytes are read and 344 * an empty byte array is returned. Otherwise, up to {@code len} bytes 345 * are read from the stream. Fewer than {@code len} bytes may be read if 346 * end of stream is encountered. 347 * 348 * <p> When this stream reaches end of stream, further invocations of this 349 * method will return an empty byte array. 350 * 351 * <p> Note that this method is intended for simple cases where it is 352 * convenient to read the specified number of bytes into a byte array. The 353 * total amount of memory allocated by this method is proportional to the 354 * number of bytes read from the stream which is bounded by {@code len}. 355 * Therefore, the method may be safely called with very large values of 356 * {@code len} provided sufficient memory is available. 357 * 358 * <p> The behavior for the case where the input stream is <i>asynchronously 359 * closed</i>, or the thread interrupted during the read, is highly input 360 * stream specific, and therefore not specified. 361 * 362 * <p> If an I/O error occurs reading from the input stream, then it may do 363 * so after some, but not all, bytes have been read. Consequently the input 364 * stream may not be at end of stream and may be in an inconsistent state. 365 * It is strongly recommended that the stream be promptly closed if an I/O 366 * error occurs. 367 * 368 * @implNote 369 * The number of bytes allocated to read data from this stream and return 370 * the result is bounded by {@code 2*(long)len}, inclusive. 371 * 372 * @param len the maximum number of bytes to read 373 * @return a byte array containing the bytes read from this input stream 374 * @throws IllegalArgumentException if {@code length} is negative 375 * @throws IOException if an I/O error occurs 376 * @throws OutOfMemoryError if an array of the required size cannot be 377 * allocated. 378 * 379 * @since 11 380 */ readNBytes(int len)381 public byte[] readNBytes(int len) throws IOException { 382 if (len < 0) { 383 throw new IllegalArgumentException("len < 0"); 384 } 385 386 List<byte[]> bufs = null; 387 byte[] result = null; 388 int total = 0; 389 int remaining = len; 390 int n; 391 do { 392 byte[] buf = new byte[Math.min(remaining, DEFAULT_BUFFER_SIZE)]; 393 int nread = 0; 394 395 // read to EOF which may read more or less than buffer size 396 while ((n = read(buf, nread, 397 Math.min(buf.length - nread, remaining))) > 0) { 398 nread += n; 399 remaining -= n; 400 } 401 402 if (nread > 0) { 403 if (MAX_BUFFER_SIZE - total < nread) { 404 throw new OutOfMemoryError("Required array size too large"); 405 } 406 total += nread; 407 if (result == null) { 408 result = buf; 409 } else { 410 if (bufs == null) { 411 bufs = new ArrayList<>(); 412 bufs.add(result); 413 } 414 bufs.add(buf); 415 } 416 } 417 // if the last call to read returned -1 or the number of bytes 418 // requested have been read then break 419 } while (n >= 0 && remaining > 0); 420 421 if (bufs == null) { 422 if (result == null) { 423 return new byte[0]; 424 } 425 return result.length == total ? 426 result : Arrays.copyOf(result, total); 427 } 428 429 result = new byte[total]; 430 int offset = 0; 431 remaining = total; 432 for (byte[] b : bufs) { 433 int count = Math.min(b.length, remaining); 434 System.arraycopy(b, 0, result, offset, count); 435 offset += count; 436 remaining -= count; 437 } 438 439 return result; 440 } 441 442 /** 443 * Reads the requested number of bytes from the input stream into the given 444 * byte array. This method blocks until {@code len} bytes of input data have 445 * been read, end of stream is detected, or an exception is thrown. The 446 * number of bytes actually read, possibly zero, is returned. This method 447 * does not close the input stream. 448 * 449 * <p> In the case where end of stream is reached before {@code len} bytes 450 * have been read, then the actual number of bytes read will be returned. 451 * When this stream reaches end of stream, further invocations of this 452 * method will return zero. 453 * 454 * <p> If {@code len} is zero, then no bytes are read and {@code 0} is 455 * returned; otherwise, there is an attempt to read up to {@code len} bytes. 456 * 457 * <p> The first byte read is stored into element {@code b[off]}, the next 458 * one in to {@code b[off+1]}, and so on. The number of bytes read is, at 459 * most, equal to {@code len}. Let <i>k</i> be the number of bytes actually 460 * read; these bytes will be stored in elements {@code b[off]} through 461 * {@code b[off+}<i>k</i>{@code -1]}, leaving elements {@code b[off+}<i>k</i> 462 * {@code ]} through {@code b[off+len-1]} unaffected. 463 * 464 * <p> The behavior for the case where the input stream is <i>asynchronously 465 * closed</i>, or the thread interrupted during the read, is highly input 466 * stream specific, and therefore not specified. 467 * 468 * <p> If an I/O error occurs reading from the input stream, then it may do 469 * so after some, but not all, bytes of {@code b} have been updated with 470 * data from the input stream. Consequently the input stream and {@code b} 471 * may be in an inconsistent state. It is strongly recommended that the 472 * stream be promptly closed if an I/O error occurs. 473 * 474 * @param b the byte array into which the data is read 475 * @param off the start offset in {@code b} at which the data is written 476 * @param len the maximum number of bytes to read 477 * @return the actual number of bytes read into the buffer 478 * @throws IOException if an I/O error occurs 479 * @throws NullPointerException if {@code b} is {@code null} 480 * @throws IndexOutOfBoundsException If {@code off} is negative, {@code len} 481 * is negative, or {@code len} is greater than {@code b.length - off} 482 * 483 * @since 9 484 */ readNBytes(byte[] b, int off, int len)485 public int readNBytes(byte[] b, int off, int len) throws IOException { 486 Objects.checkFromIndexSize(off, len, b.length); 487 488 int n = 0; 489 while (n < len) { 490 int count = read(b, off + n, len - n); 491 if (count < 0) 492 break; 493 n += count; 494 } 495 return n; 496 } 497 498 /** 499 * Skips over and discards <code>n</code> bytes of data from this input 500 * stream. The <code>skip</code> method may, for a variety of reasons, end 501 * up skipping over some smaller number of bytes, possibly <code>0</code>. 502 * This may result from any of a number of conditions; reaching end of file 503 * before <code>n</code> bytes have been skipped is only one possibility. 504 * The actual number of bytes skipped is returned. If {@code n} is 505 * negative, the {@code skip} method for class {@code InputStream} always 506 * returns 0, and no bytes are skipped. Subclasses may handle the negative 507 * value differently. 508 * 509 * <p> The <code>skip</code> method implementation of this class creates a 510 * byte array and then repeatedly reads into it until <code>n</code> bytes 511 * have been read or the end of the stream has been reached. Subclasses are 512 * encouraged to provide a more efficient implementation of this method. 513 * For instance, the implementation may depend on the ability to seek. 514 * 515 * @param n the number of bytes to be skipped. 516 * @return the actual number of bytes skipped. 517 * @throws IOException if an I/O error occurs. 518 */ skip(long n)519 public long skip(long n) throws IOException { 520 521 long remaining = n; 522 int nr; 523 524 if (n <= 0) { 525 return 0; 526 } 527 528 int size = (int)Math.min(MAX_SKIP_BUFFER_SIZE, remaining); 529 byte[] skipBuffer = new byte[size]; 530 while (remaining > 0) { 531 nr = read(skipBuffer, 0, (int)Math.min(size, remaining)); 532 if (nr < 0) { 533 break; 534 } 535 remaining -= nr; 536 } 537 538 return n - remaining; 539 } 540 541 /** 542 * Returns an estimate of the number of bytes that can be read (or skipped 543 * over) from this input stream without blocking, which may be 0, or 0 when 544 * end of stream is detected. The read might be on the same thread or 545 * another thread. A single read or skip of this many bytes will not block, 546 * but may read or skip fewer bytes. 547 * 548 * <p> Note that while some implementations of {@code InputStream} will 549 * return the total number of bytes in the stream, many will not. It is 550 * never correct to use the return value of this method to allocate 551 * a buffer intended to hold all data in this stream. 552 * 553 * <p> A subclass's implementation of this method may choose to throw an 554 * {@link IOException} if this input stream has been closed by invoking the 555 * {@link #close()} method. 556 * 557 * <p> The {@code available} method of {@code InputStream} always returns 558 * {@code 0}. 559 * 560 * <p> This method should be overridden by subclasses. 561 * 562 * @return an estimate of the number of bytes that can be read (or 563 * skipped over) from this input stream without blocking or 564 * {@code 0} when it reaches the end of the input stream. 565 * @exception IOException if an I/O error occurs. 566 */ available()567 public int available() throws IOException { 568 return 0; 569 } 570 571 /** 572 * Closes this input stream and releases any system resources associated 573 * with the stream. 574 * 575 * <p> The <code>close</code> method of <code>InputStream</code> does 576 * nothing. 577 * 578 * @exception IOException if an I/O error occurs. 579 */ close()580 public void close() throws IOException {} 581 582 /** 583 * Marks the current position in this input stream. A subsequent call to 584 * the <code>reset</code> method repositions this stream at the last marked 585 * position so that subsequent reads re-read the same bytes. 586 * 587 * <p> The <code>readlimit</code> arguments tells this input stream to 588 * allow that many bytes to be read before the mark position gets 589 * invalidated. 590 * 591 * <p> The general contract of <code>mark</code> is that, if the method 592 * <code>markSupported</code> returns <code>true</code>, the stream somehow 593 * remembers all the bytes read after the call to <code>mark</code> and 594 * stands ready to supply those same bytes again if and whenever the method 595 * <code>reset</code> is called. However, the stream is not required to 596 * remember any data at all if more than <code>readlimit</code> bytes are 597 * read from the stream before <code>reset</code> is called. 598 * 599 * <p> Marking a closed stream should not have any effect on the stream. 600 * 601 * <p> The <code>mark</code> method of <code>InputStream</code> does 602 * nothing. 603 * 604 * @param readlimit the maximum limit of bytes that can be read before 605 * the mark position becomes invalid. 606 * @see java.io.InputStream#reset() 607 */ mark(int readlimit)608 public synchronized void mark(int readlimit) {} 609 610 /** 611 * Repositions this stream to the position at the time the 612 * <code>mark</code> method was last called on this input stream. 613 * 614 * <p> The general contract of <code>reset</code> is: 615 * 616 * <ul> 617 * <li> If the method <code>markSupported</code> returns 618 * <code>true</code>, then: 619 * 620 * <ul><li> If the method <code>mark</code> has not been called since 621 * the stream was created, or the number of bytes read from the stream 622 * since <code>mark</code> was last called is larger than the argument 623 * to <code>mark</code> at that last call, then an 624 * <code>IOException</code> might be thrown. 625 * 626 * <li> If such an <code>IOException</code> is not thrown, then the 627 * stream is reset to a state such that all the bytes read since the 628 * most recent call to <code>mark</code> (or since the start of the 629 * file, if <code>mark</code> has not been called) will be resupplied 630 * to subsequent callers of the <code>read</code> method, followed by 631 * any bytes that otherwise would have been the next input data as of 632 * the time of the call to <code>reset</code>. </ul> 633 * 634 * <li> If the method <code>markSupported</code> returns 635 * <code>false</code>, then: 636 * 637 * <ul><li> The call to <code>reset</code> may throw an 638 * <code>IOException</code>. 639 * 640 * <li> If an <code>IOException</code> is not thrown, then the stream 641 * is reset to a fixed state that depends on the particular type of the 642 * input stream and how it was created. The bytes that will be supplied 643 * to subsequent callers of the <code>read</code> method depend on the 644 * particular type of the input stream. </ul></ul> 645 * 646 * <p>The method <code>reset</code> for class <code>InputStream</code> 647 * does nothing except throw an <code>IOException</code>. 648 * 649 * @exception IOException if this stream has not been marked or if the 650 * mark has been invalidated. 651 * @see java.io.InputStream#mark(int) 652 * @see java.io.IOException 653 */ reset()654 public synchronized void reset() throws IOException { 655 throw new IOException("mark/reset not supported"); 656 } 657 658 /** 659 * Tests if this input stream supports the <code>mark</code> and 660 * <code>reset</code> methods. Whether or not <code>mark</code> and 661 * <code>reset</code> are supported is an invariant property of a 662 * particular input stream instance. The <code>markSupported</code> method 663 * of <code>InputStream</code> returns <code>false</code>. 664 * 665 * @return <code>true</code> if this stream instance supports the mark 666 * and reset methods; <code>false</code> otherwise. 667 * @see java.io.InputStream#mark(int) 668 * @see java.io.InputStream#reset() 669 */ markSupported()670 public boolean markSupported() { 671 return false; 672 } 673 674 /** 675 * Reads all bytes from this input stream and writes the bytes to the 676 * given output stream in the order that they are read. On return, this 677 * input stream will be at end of stream. This method does not close either 678 * stream. 679 * <p> 680 * This method may block indefinitely reading from the input stream, or 681 * writing to the output stream. The behavior for the case where the input 682 * and/or output stream is <i>asynchronously closed</i>, or the thread 683 * interrupted during the transfer, is highly input and output stream 684 * specific, and therefore not specified. 685 * <p> 686 * If an I/O error occurs reading from the input stream or writing to the 687 * output stream, then it may do so after some bytes have been read or 688 * written. Consequently the input stream may not be at end of stream and 689 * one, or both, streams may be in an inconsistent state. It is strongly 690 * recommended that both streams be promptly closed if an I/O error occurs. 691 * 692 * @param out the output stream, non-null 693 * @return the number of bytes transferred 694 * @throws IOException if an I/O error occurs when reading or writing 695 * @throws NullPointerException if {@code out} is {@code null} 696 * 697 * @since 9 698 */ transferTo(OutputStream out)699 public long transferTo(OutputStream out) throws IOException { 700 Objects.requireNonNull(out, "out"); 701 long transferred = 0; 702 byte[] buffer = new byte[DEFAULT_BUFFER_SIZE]; 703 int read; 704 while ((read = this.read(buffer, 0, DEFAULT_BUFFER_SIZE)) >= 0) { 705 out.write(buffer, 0, read); 706 transferred += read; 707 } 708 return transferred; 709 } 710 } 711