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 */
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 */
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 */
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 */
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 */
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 * @param len the maximum number of bytes to read
369 * @return a byte array containing the bytes read from this input stream
370 * @throws IllegalArgumentException if {@code length} is negative
371 * @throws IOException if an I/O error occurs
372 * @throws OutOfMemoryError if an array of the required size cannot be
373 * allocated.
374 *
375 * @since 11
376 */
377 public byte[] readNBytes(int len) throws IOException {
378 if (len < 0) {
379 throw new IllegalArgumentException("len < 0");
380 }
381
382 List<byte[]> bufs = null;
383 byte[] result = null;
384 int total = 0;
385 int remaining = len;
386 int n;
387 do {
388 byte[] buf = new byte[Math.min(len, DEFAULT_BUFFER_SIZE)];
389 int nread = 0;
390
391 // read to EOF which may read more or less than buffer size
392 while ((n = read(buf, nread,
393 Math.min(buf.length - nread, remaining))) > 0) {
394 nread += n;
395 remaining -= n;
396 }
397
398 if (nread > 0) {
399 if (MAX_BUFFER_SIZE - total < nread) {
400 throw new OutOfMemoryError("Required array size too large");
401 }
402 total += nread;
403 if (result == null) {
404 result = buf;
405 } else {
406 if (bufs == null) {
407 bufs = new ArrayList<>();
408 bufs.add(result);
409 }
410 bufs.add(buf);
411 }
412 }
413 // if the last call to read returned -1 or the number of bytes
414 // requested have been read then break
415 } while (n >= 0 && remaining > 0);
416
417 if (bufs == null) {
418 if (result == null) {
419 return new byte[0];
420 }
421 return result.length == total ?
422 result : Arrays.copyOf(result, total);
423 }
424
425 result = new byte[total];
426 int offset = 0;
427 remaining = total;
428 for (byte[] b : bufs) {
429 int count = Math.min(b.length, remaining);
430 System.arraycopy(b, 0, result, offset, count);
431 offset += count;
432 remaining -= count;
433 }
434
435 return result;
436 }
437
438 /**
439 * Reads the requested number of bytes from the input stream into the given
440 * byte array. This method blocks until {@code len} bytes of input data have
441 * been read, end of stream is detected, or an exception is thrown. The
442 * number of bytes actually read, possibly zero, is returned. This method
443 * does not close the input stream.
444 *
445 * <p> In the case where end of stream is reached before {@code len} bytes
446 * have been read, then the actual number of bytes read will be returned.
447 * When this stream reaches end of stream, further invocations of this
448 * method will return zero.
449 *
450 * <p> If {@code len} is zero, then no bytes are read and {@code 0} is
451 * returned; otherwise, there is an attempt to read up to {@code len} bytes.
452 *
453 * <p> The first byte read is stored into element {@code b[off]}, the next
454 * one in to {@code b[off+1]}, and so on. The number of bytes read is, at
455 * most, equal to {@code len}. Let <i>k</i> be the number of bytes actually
456 * read; these bytes will be stored in elements {@code b[off]} through
457 * {@code b[off+}<i>k</i>{@code -1]}, leaving elements {@code b[off+}<i>k</i>
458 * {@code ]} through {@code b[off+len-1]} unaffected.
459 *
460 * <p> The behavior for the case where the input stream is <i>asynchronously
461 * closed</i>, or the thread interrupted during the read, is highly input
462 * stream specific, and therefore not specified.
463 *
464 * <p> If an I/O error occurs reading from the input stream, then it may do
465 * so after some, but not all, bytes of {@code b} have been updated with
466 * data from the input stream. Consequently the input stream and {@code b}
467 * may be in an inconsistent state. It is strongly recommended that the
468 * stream be promptly closed if an I/O error occurs.
469 *
470 * @param b the byte array into which the data is read
471 * @param off the start offset in {@code b} at which the data is written
472 * @param len the maximum number of bytes to read
473 * @return the actual number of bytes read into the buffer
474 * @throws IOException if an I/O error occurs
475 * @throws NullPointerException if {@code b} is {@code null}
476 * @throws IndexOutOfBoundsException If {@code off} is negative, {@code len}
477 * is negative, or {@code len} is greater than {@code b.length - off}
478 *
479 * @since 9
480 */
481 public int readNBytes(byte[] b, int off, int len) throws IOException {
482 Objects.checkFromIndexSize(off, len, b.length);
483
484 int n = 0;
485 while (n < len) {
486 int count = read(b, off + n, len - n);
487 if (count < 0)
488 break;
489 n += count;
490 }
491 return n;
492 }
493
494 /**
495 * Skips over and discards <code>n</code> bytes of data from this input
496 * stream. The <code>skip</code> method may, for a variety of reasons, end
497 * up skipping over some smaller number of bytes, possibly <code>0</code>.
498 * This may result from any of a number of conditions; reaching end of file
499 * before <code>n</code> bytes have been skipped is only one possibility.
500 * The actual number of bytes skipped is returned. If {@code n} is
501 * negative, the {@code skip} method for class {@code InputStream} always
502 * returns 0, and no bytes are skipped. Subclasses may handle the negative
503 * value differently.
504 *
505 * <p> The <code>skip</code> method implementation of this class creates a
506 * byte array and then repeatedly reads into it until <code>n</code> bytes
507 * have been read or the end of the stream has been reached. Subclasses are
508 * encouraged to provide a more efficient implementation of this method.
509 * For instance, the implementation may depend on the ability to seek.
510 *
511 * @param n the number of bytes to be skipped.
512 * @return the actual number of bytes skipped.
513 * @throws IOException if an I/O error occurs.
514 */
515 public long skip(long n) throws IOException {
516
517 long remaining = n;
518 int nr;
519
520 if (n <= 0) {
521 return 0;
522 }
523
524 int size = (int)Math.min(MAX_SKIP_BUFFER_SIZE, remaining);
525 byte[] skipBuffer = new byte[size];
526 while (remaining > 0) {
527 nr = read(skipBuffer, 0, (int)Math.min(size, remaining));
528 if (nr < 0) {
529 break;
530 }
531 remaining -= nr;
532 }
533
534 return n - remaining;
535 }
536
537 /**
538 * Returns an estimate of the number of bytes that can be read (or
539 * skipped over) from this input stream without blocking by the next
540 * invocation of a method for this input stream. The next invocation
541 * might be the same thread or another thread. A single read or skip of this
542 * many bytes will not block, but may read or skip fewer bytes.
543 *
544 * <p> Note that while some implementations of {@code InputStream} will return
545 * the total number of bytes in the stream, many will not. It is
546 * never correct to use the return value of this method to allocate
547 * a buffer intended to hold all data in this stream.
548 *
549 * <p> A subclass' implementation of this method may choose to throw an
550 * {@link IOException} if this input stream has been closed by
551 * invoking the {@link #close()} method.
552 *
553 * <p> The {@code available} method for class {@code InputStream} always
554 * returns {@code 0}.
555 *
556 * <p> This method should be overridden by subclasses.
557 *
558 * @return an estimate of the number of bytes that can be read (or skipped
559 * over) from this input stream without blocking or {@code 0} when
560 * it reaches the end of the input stream.
561 * @exception IOException if an I/O error occurs.
562 */
563 public int available() throws IOException {
564 return 0;
565 }
566
567 /**
568 * Closes this input stream and releases any system resources associated
569 * with the stream.
570 *
571 * <p> The <code>close</code> method of <code>InputStream</code> does
572 * nothing.
573 *
574 * @exception IOException if an I/O error occurs.
575 */
576 public void close() throws IOException {}
577
578 /**
579 * Marks the current position in this input stream. A subsequent call to
580 * the <code>reset</code> method repositions this stream at the last marked
581 * position so that subsequent reads re-read the same bytes.
582 *
583 * <p> The <code>readlimit</code> arguments tells this input stream to
584 * allow that many bytes to be read before the mark position gets
585 * invalidated.
586 *
587 * <p> The general contract of <code>mark</code> is that, if the method
588 * <code>markSupported</code> returns <code>true</code>, the stream somehow
589 * remembers all the bytes read after the call to <code>mark</code> and
590 * stands ready to supply those same bytes again if and whenever the method
591 * <code>reset</code> is called. However, the stream is not required to
592 * remember any data at all if more than <code>readlimit</code> bytes are
593 * read from the stream before <code>reset</code> is called.
594 *
595 * <p> Marking a closed stream should not have any effect on the stream.
596 *
597 * <p> The <code>mark</code> method of <code>InputStream</code> does
598 * nothing.
599 *
600 * @param readlimit the maximum limit of bytes that can be read before
601 * the mark position becomes invalid.
602 * @see java.io.InputStream#reset()
603 */
604 public synchronized void mark(int readlimit) {}
605
606 /**
607 * Repositions this stream to the position at the time the
608 * <code>mark</code> method was last called on this input stream.
609 *
610 * <p> The general contract of <code>reset</code> is:
611 *
612 * <ul>
613 * <li> If the method <code>markSupported</code> returns
614 * <code>true</code>, then:
615 *
616 * <ul><li> If the method <code>mark</code> has not been called since
617 * the stream was created, or the number of bytes read from the stream
618 * since <code>mark</code> was last called is larger than the argument
619 * to <code>mark</code> at that last call, then an
620 * <code>IOException</code> might be thrown.
621 *
622 * <li> If such an <code>IOException</code> is not thrown, then the
623 * stream is reset to a state such that all the bytes read since the
624 * most recent call to <code>mark</code> (or since the start of the
625 * file, if <code>mark</code> has not been called) will be resupplied
626 * to subsequent callers of the <code>read</code> method, followed by
627 * any bytes that otherwise would have been the next input data as of
628 * the time of the call to <code>reset</code>. </ul>
629 *
630 * <li> If the method <code>markSupported</code> returns
631 * <code>false</code>, then:
632 *
633 * <ul><li> The call to <code>reset</code> may throw an
634 * <code>IOException</code>.
635 *
636 * <li> If an <code>IOException</code> is not thrown, then the stream
637 * is reset to a fixed state that depends on the particular type of the
638 * input stream and how it was created. The bytes that will be supplied
639 * to subsequent callers of the <code>read</code> method depend on the
640 * particular type of the input stream. </ul></ul>
641 *
642 * <p>The method <code>reset</code> for class <code>InputStream</code>
643 * does nothing except throw an <code>IOException</code>.
644 *
645 * @exception IOException if this stream has not been marked or if the
646 * mark has been invalidated.
647 * @see java.io.InputStream#mark(int)
648 * @see java.io.IOException
649 */
650 public synchronized void reset() throws IOException {
651 throw new IOException("mark/reset not supported");
652 }
653
654 /**
655 * Tests if this input stream supports the <code>mark</code> and
656 * <code>reset</code> methods. Whether or not <code>mark</code> and
657 * <code>reset</code> are supported is an invariant property of a
658 * particular input stream instance. The <code>markSupported</code> method
659 * of <code>InputStream</code> returns <code>false</code>.
660 *
661 * @return <code>true</code> if this stream instance supports the mark
662 * and reset methods; <code>false</code> otherwise.
663 * @see java.io.InputStream#mark(int)
664 * @see java.io.InputStream#reset()
665 */
666 public boolean markSupported() {
667 return false;
668 }
669
670 /**
671 * Reads all bytes from this input stream and writes the bytes to the
672 * given output stream in the order that they are read. On return, this
673 * input stream will be at end of stream. This method does not close either
674 * stream.
675 * <p>
676 * This method may block indefinitely reading from the input stream, or
677 * writing to the output stream. The behavior for the case where the input
678 * and/or output stream is <i>asynchronously closed</i>, or the thread
679 * interrupted during the transfer, is highly input and output stream
680 * specific, and therefore not specified.
681 * <p>
682 * If an I/O error occurs reading from the input stream or writing to the
683 * output stream, then it may do so after some bytes have been read or
684 * written. Consequently the input stream may not be at end of stream and
685 * one, or both, streams may be in an inconsistent state. It is strongly
686 * recommended that both streams be promptly closed if an I/O error occurs.
687 *
688 * @param out the output stream, non-null
689 * @return the number of bytes transferred
690 * @throws IOException if an I/O error occurs when reading or writing
691 * @throws NullPointerException if {@code out} is {@code null}
692 *
693 * @since 9
694 */
695 public long transferTo(OutputStream out) throws IOException {
696 Objects.requireNonNull(out, "out");
697 long transferred = 0;
698 byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
699 int read;
700 while ((read = this.read(buffer, 0, DEFAULT_BUFFER_SIZE)) >= 0) {
701 out.write(buffer, 0, read);
702 transferred += read;
703 }
704 return transferred;
705 }
706 }