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)}, {@code skipNBytes(long)},
68 * and {@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 void skipNBytes(long n) throws IOException {
143 ensureOpen();
144 if (n > 0) {
145 throw new EOFException();
146 }
147 }
148
149 @Override
150 public long transferTo(OutputStream out) throws IOException {
151 Objects.requireNonNull(out);
152 ensureOpen();
153 return 0L;
154 }
155
156 @Override
157 public void close() throws IOException {
158 closed = true;
159 }
160 };
161 }
162
163 /**
164 * Reads the next byte of data from the input stream. The value byte is
165 * returned as an <code>int</code> in the range <code>0</code> to
166 * <code>255</code>. If no byte is available because the end of the stream
167 * has been reached, the value <code>-1</code> is returned. This method
168 * blocks until input data is available, the end of the stream is detected,
169 * or an exception is thrown.
170 *
171 * <p> A subclass must provide an implementation of this method.
172 *
173 * @return the next byte of data, or <code>-1</code> if the end of the
174 * stream is reached.
175 * @exception IOException if an I/O error occurs.
176 */
177 public abstract int read() throws IOException;
178
179 /**
180 * Reads some number of bytes from the input stream and stores them into
181 * the buffer array <code>b</code>. The number of bytes actually read is
182 * returned as an integer. This method blocks until input data is
183 * available, end of file is detected, or an exception is thrown.
184 *
185 * <p> If the length of <code>b</code> is zero, then no bytes are read and
186 * <code>0</code> is returned; otherwise, there is an attempt to read at
187 * least one byte. If no byte is available because the stream is at the
188 * end of the file, the value <code>-1</code> is returned; otherwise, at
189 * least one byte is read and stored into <code>b</code>.
190 *
191 * <p> The first byte read is stored into element <code>b[0]</code>, the
192 * next one into <code>b[1]</code>, and so on. The number of bytes read is,
193 * at most, equal to the length of <code>b</code>. Let <i>k</i> be the
194 * number of bytes actually read; these bytes will be stored in elements
195 * <code>b[0]</code> through <code>b[</code><i>k</i><code>-1]</code>,
196 * leaving elements <code>b[</code><i>k</i><code>]</code> through
197 * <code>b[b.length-1]</code> unaffected.
198 *
199 * <p> The <code>read(b)</code> method for class <code>InputStream</code>
200 * has the same effect as: <pre><code> read(b, 0, b.length) </code></pre>
201 *
202 * @param b the buffer into which the data is read.
203 * @return the total number of bytes read into the buffer, or
204 * <code>-1</code> if there is no more data because the end of
205 * the stream has been reached.
206 * @exception IOException If the first byte cannot be read for any reason
207 * other than the end of the file, if the input stream has been closed, or
208 * if some other I/O error occurs.
209 * @exception NullPointerException if <code>b</code> is <code>null</code>.
210 * @see java.io.InputStream#read(byte[], int, int)
211 */
212 public int read(byte b[]) throws IOException {
213 return read(b, 0, b.length);
214 }
215
216 /**
217 * Reads up to <code>len</code> bytes of data from the input stream into
218 * an array of bytes. An attempt is made to read as many as
219 * <code>len</code> bytes, but a smaller number may be read.
220 * The number of bytes actually read is returned as an integer.
221 *
222 * <p> This method blocks until input data is available, end of file is
223 * detected, or an exception is thrown.
224 *
225 * <p> If <code>len</code> is zero, then no bytes are read and
226 * <code>0</code> is returned; otherwise, there is an attempt to read at
227 * least one byte. If no byte is available because the stream is at end of
228 * file, the value <code>-1</code> is returned; otherwise, at least one
229 * byte is read and stored into <code>b</code>.
230 *
231 * <p> The first byte read is stored into element <code>b[off]</code>, the
232 * next one into <code>b[off+1]</code>, and so on. The number of bytes read
233 * is, at most, equal to <code>len</code>. Let <i>k</i> be the number of
234 * bytes actually read; these bytes will be stored in elements
235 * <code>b[off]</code> through <code>b[off+</code><i>k</i><code>-1]</code>,
236 * leaving elements <code>b[off+</code><i>k</i><code>]</code> through
237 * <code>b[off+len-1]</code> unaffected.
238 *
239 * <p> In every case, elements <code>b[0]</code> through
240 * <code>b[off]</code> and elements <code>b[off+len]</code> through
241 * <code>b[b.length-1]</code> are unaffected.
242 *
243 * <p> The <code>read(b,</code> <code>off,</code> <code>len)</code> method
244 * for class <code>InputStream</code> simply calls the method
245 * <code>read()</code> repeatedly. If the first such call results in an
246 * <code>IOException</code>, that exception is returned from the call to
247 * the <code>read(b,</code> <code>off,</code> <code>len)</code> method. If
248 * any subsequent call to <code>read()</code> results in a
249 * <code>IOException</code>, the exception is caught and treated as if it
250 * were end of file; the bytes read up to that point are stored into
251 * <code>b</code> and the number of bytes read before the exception
252 * occurred is returned. The default implementation of this method blocks
253 * until the requested amount of input data <code>len</code> has been read,
254 * end of file is detected, or an exception is thrown. Subclasses are
255 * encouraged to provide a more efficient implementation of this method.
256 *
257 * @param b the buffer into which the data is read.
258 * @param off the start offset in array <code>b</code>
259 * at which the data is written.
260 * @param len the maximum number of bytes to read.
261 * @return the total number of bytes read into the buffer, or
262 * <code>-1</code> if there is no more data because the end of
263 * the stream has been reached.
264 * @exception IOException If the first byte cannot be read for any reason
265 * other than end of file, or if the input stream has been closed, or if
266 * some other I/O error occurs.
267 * @exception NullPointerException If <code>b</code> is <code>null</code>.
268 * @exception IndexOutOfBoundsException If <code>off</code> is negative,
269 * <code>len</code> is negative, or <code>len</code> is greater than
270 * <code>b.length - off</code>
271 * @see java.io.InputStream#read()
272 */
273 public int read(byte b[], int off, int len) throws IOException {
274 Objects.checkFromIndexSize(off, len, b.length);
275 if (len == 0) {
276 return 0;
277 }
278
279 int c = read();
280 if (c == -1) {
281 return -1;
282 }
283 b[off] = (byte)c;
284
285 int i = 1;
286 try {
287 for (; i < len ; i++) {
288 c = read();
289 if (c == -1) {
290 break;
291 }
292 b[off + i] = (byte)c;
293 }
294 } catch (IOException ee) {
295 }
296 return i;
297 }
298
299 /**
300 * The maximum size of array to allocate.
301 * Some VMs reserve some header words in an array.
302 * Attempts to allocate larger arrays may result in
303 * OutOfMemoryError: Requested array size exceeds VM limit
304 */
305 private static final int MAX_BUFFER_SIZE = Integer.MAX_VALUE - 8;
306
307 /**
308 * Reads all remaining bytes from the input stream. This method blocks until
309 * all remaining bytes have been read and end of stream is detected, or an
310 * exception is thrown. This method does not close the input stream.
311 *
312 * <p> When this stream reaches end of stream, further invocations of this
313 * method will return an empty byte array.
314 *
315 * <p> Note that this method is intended for simple cases where it is
316 * convenient to read all bytes into a byte array. It is not intended for
317 * reading input streams with large amounts of data.
318 *
319 * <p> The behavior for the case where the input stream is <i>asynchronously
320 * closed</i>, or the thread interrupted during the read, is highly input
321 * stream specific, and therefore not specified.
322 *
323 * <p> If an I/O error occurs reading from the input stream, then it may do
324 * so after some, but not all, bytes have been read. Consequently the input
325 * stream may not be at end of stream and may be in an inconsistent state.
326 * It is strongly recommended that the stream be promptly closed if an I/O
327 * error occurs.
328 *
329 * @implSpec
330 * This method invokes {@link #readNBytes(int)} with a length of
331 * {@link Integer#MAX_VALUE}.
332 *
333 * @return a byte array containing the bytes read from this input stream
334 * @throws IOException if an I/O error occurs
335 * @throws OutOfMemoryError if an array of the required size cannot be
336 * allocated.
337 *
338 * @since 9
339 */
340 public byte[] readAllBytes() throws IOException {
341 return readNBytes(Integer.MAX_VALUE);
342 }
343
344 /**
345 * Reads up to a specified number of bytes from the input stream. This
346 * method blocks until the requested number of bytes have been read, end
347 * of stream is detected, or an exception is thrown. This method does not
348 * close the input stream.
349 *
350 * <p> The length of the returned array equals the number of bytes read
351 * from the stream. If {@code len} is zero, then no bytes are read and
352 * an empty byte array is returned. Otherwise, up to {@code len} bytes
353 * are read from the stream. Fewer than {@code len} bytes may be read if
354 * end of stream is encountered.
355 *
356 * <p> When this stream reaches end of stream, further invocations of this
357 * method will return an empty byte array.
358 *
359 * <p> Note that this method is intended for simple cases where it is
360 * convenient to read the specified number of bytes into a byte array. The
361 * total amount of memory allocated by this method is proportional to the
362 * number of bytes read from the stream which is bounded by {@code len}.
363 * Therefore, the method may be safely called with very large values of
364 * {@code len} provided sufficient memory is available.
365 *
366 * <p> The behavior for the case where the input stream is <i>asynchronously
367 * closed</i>, or the thread interrupted during the read, is highly input
368 * stream specific, and therefore not specified.
369 *
370 * <p> If an I/O error occurs reading from the input stream, then it may do
371 * so after some, but not all, bytes have been read. Consequently the input
372 * stream may not be at end of stream and may be in an inconsistent state.
373 * It is strongly recommended that the stream be promptly closed if an I/O
374 * error occurs.
375 *
376 * @implNote
377 * The number of bytes allocated to read data from this stream and return
378 * the result is bounded by {@code 2*(long)len}, inclusive.
379 *
380 * @param len the maximum number of bytes to read
381 * @return a byte array containing the bytes read from this input stream
382 * @throws IllegalArgumentException if {@code length} is negative
383 * @throws IOException if an I/O error occurs
384 * @throws OutOfMemoryError if an array of the required size cannot be
385 * allocated.
386 *
387 * @since 11
388 */
389 public byte[] readNBytes(int len) throws IOException {
390 if (len < 0) {
391 throw new IllegalArgumentException("len < 0");
392 }
393
394 List<byte[]> bufs = null;
395 byte[] result = null;
396 int total = 0;
397 int remaining = len;
398 int n;
399 do {
400 byte[] buf = new byte[Math.min(remaining, DEFAULT_BUFFER_SIZE)];
401 int nread = 0;
402
403 // read to EOF which may read more or less than buffer size
404 while ((n = read(buf, nread,
405 Math.min(buf.length - nread, remaining))) > 0) {
406 nread += n;
407 remaining -= n;
408 }
409
410 if (nread > 0) {
411 if (MAX_BUFFER_SIZE - total < nread) {
412 throw new OutOfMemoryError("Required array size too large");
413 }
414 total += nread;
415 if (result == null) {
416 result = buf;
417 } else {
418 if (bufs == null) {
419 bufs = new ArrayList<>();
420 bufs.add(result);
421 }
422 bufs.add(buf);
423 }
424 }
425 // if the last call to read returned -1 or the number of bytes
426 // requested have been read then break
427 } while (n >= 0 && remaining > 0);
428
429 if (bufs == null) {
430 if (result == null) {
431 return new byte[0];
432 }
433 return result.length == total ?
434 result : Arrays.copyOf(result, total);
435 }
436
437 result = new byte[total];
438 int offset = 0;
439 remaining = total;
440 for (byte[] b : bufs) {
441 int count = Math.min(b.length, remaining);
442 System.arraycopy(b, 0, result, offset, count);
443 offset += count;
444 remaining -= count;
445 }
446
447 return result;
448 }
449
450 /**
451 * Reads the requested number of bytes from the input stream into the given
452 * byte array. This method blocks until {@code len} bytes of input data have
453 * been read, end of stream is detected, or an exception is thrown. The
454 * number of bytes actually read, possibly zero, is returned. This method
455 * does not close the input stream.
456 *
457 * <p> In the case where end of stream is reached before {@code len} bytes
458 * have been read, then the actual number of bytes read will be returned.
459 * When this stream reaches end of stream, further invocations of this
460 * method will return zero.
461 *
462 * <p> If {@code len} is zero, then no bytes are read and {@code 0} is
463 * returned; otherwise, there is an attempt to read up to {@code len} bytes.
464 *
465 * <p> The first byte read is stored into element {@code b[off]}, the next
466 * one in to {@code b[off+1]}, and so on. The number of bytes read is, at
467 * most, equal to {@code len}. Let <i>k</i> be the number of bytes actually
468 * read; these bytes will be stored in elements {@code b[off]} through
469 * {@code b[off+}<i>k</i>{@code -1]}, leaving elements {@code b[off+}<i>k</i>
470 * {@code ]} through {@code b[off+len-1]} unaffected.
471 *
472 * <p> The behavior for the case where the input stream is <i>asynchronously
473 * closed</i>, or the thread interrupted during the read, is highly input
474 * stream specific, and therefore not specified.
475 *
476 * <p> If an I/O error occurs reading from the input stream, then it may do
477 * so after some, but not all, bytes of {@code b} have been updated with
478 * data from the input stream. Consequently the input stream and {@code b}
479 * may be in an inconsistent state. It is strongly recommended that the
480 * stream be promptly closed if an I/O error occurs.
481 *
482 * @param b the byte array into which the data is read
483 * @param off the start offset in {@code b} at which the data is written
484 * @param len the maximum number of bytes to read
485 * @return the actual number of bytes read into the buffer
486 * @throws IOException if an I/O error occurs
487 * @throws NullPointerException if {@code b} is {@code null}
488 * @throws IndexOutOfBoundsException If {@code off} is negative, {@code len}
489 * is negative, or {@code len} is greater than {@code b.length - off}
490 *
491 * @since 9
492 */
493 public int readNBytes(byte[] b, int off, int len) throws IOException {
494 Objects.checkFromIndexSize(off, len, b.length);
495
496 int n = 0;
497 while (n < len) {
498 int count = read(b, off + n, len - n);
499 if (count < 0)
500 break;
501 n += count;
502 }
503 return n;
504 }
505
506 /**
507 * Skips over and discards <code>n</code> bytes of data from this input
508 * stream. The <code>skip</code> method may, for a variety of reasons, end
509 * up skipping over some smaller number of bytes, possibly <code>0</code>.
510 * This may result from any of a number of conditions; reaching end of file
511 * before <code>n</code> bytes have been skipped is only one possibility.
512 * The actual number of bytes skipped is returned. If {@code n} is
513 * negative, the {@code skip} method for class {@code InputStream} always
514 * returns 0, and no bytes are skipped. Subclasses may handle the negative
515 * value differently.
516 *
517 * <p> The <code>skip</code> method implementation of this class creates a
518 * byte array and then repeatedly reads into it until <code>n</code> bytes
519 * have been read or the end of the stream has been reached. Subclasses are
520 * encouraged to provide a more efficient implementation of this method.
521 * For instance, the implementation may depend on the ability to seek.
522 *
523 * @param n the number of bytes to be skipped.
524 * @return the actual number of bytes skipped which might be zero.
525 * @throws IOException if an I/O error occurs.
526 */
527 public long skip(long n) throws IOException {
528 long remaining = n;
529 int nr;
530
531 if (n <= 0) {
532 return 0;
533 }
534
535 int size = (int)Math.min(MAX_SKIP_BUFFER_SIZE, remaining);
536 byte[] skipBuffer = new byte[size];
537 while (remaining > 0) {
538 nr = read(skipBuffer, 0, (int)Math.min(size, remaining));
539 if (nr < 0) {
540 break;
541 }
542 remaining -= nr;
543 }
544
545 return n - remaining;
546 }
547
548 /**
549 * Skips over and discards exactly {@code n} bytes of data from this input
550 * stream. If {@code n <= 0}, no bytes are skipped. If {@code n > 0},
551 * then {@code n} bytes of data are skipped unless end of stream is
552 * encountered first, in which case an {@code EOFException} is thrown.
553 *
554 * <p> This method blocks until data is available to skip, end of file is
555 * detected, or an exception is thrown.
556 *
557 * @param n the number of bytes to be skipped.
558 * @throws EOFException if end of stream is encountered before {@code n}
559 * bytes are skipped.
560 * @throws IOException if an I/O error occurs.
561 */
562 public void skipNBytes(long n) throws IOException {
563 if (n > 0 && skip(n) != n) {
564 throw new EOFException("End of stream before enough bytes skipped");
565 }
566 }
567
568 /**
569 * Returns an estimate of the number of bytes that can be read (or skipped
570 * over) from this input stream without blocking, which may be 0, or 0 when
571 * end of stream is detected. The read might be on the same thread or
572 * another thread. A single read or skip of this many bytes will not block,
573 * but may read or skip fewer bytes.
574 *
575 * <p> Note that while some implementations of {@code InputStream} will
576 * return the total number of bytes in the stream, many will not. It is
577 * never correct to use the return value of this method to allocate
578 * a buffer intended to hold all data in this stream.
579 *
580 * <p> A subclass's implementation of this method may choose to throw an
581 * {@link IOException} if this input stream has been closed by invoking the
582 * {@link #close()} method.
583 *
584 * <p> The {@code available} method of {@code InputStream} always returns
585 * {@code 0}.
586 *
587 * <p> This method should be overridden by subclasses.
588 *
589 * @return an estimate of the number of bytes that can be read (or
590 * skipped over) from this input stream without blocking or
591 * {@code 0} when it reaches the end of the input stream.
592 * @exception IOException if an I/O error occurs.
593 */
594 public int available() throws IOException {
595 return 0;
596 }
597
598 /**
599 * Closes this input stream and releases any system resources associated
600 * with the stream.
601 *
602 * <p> The <code>close</code> method of <code>InputStream</code> does
603 * nothing.
604 *
605 * @exception IOException if an I/O error occurs.
606 */
607 public void close() throws IOException {}
608
609 /**
610 * Marks the current position in this input stream. A subsequent call to
611 * the <code>reset</code> method repositions this stream at the last marked
612 * position so that subsequent reads re-read the same bytes.
613 *
614 * <p> The <code>readlimit</code> arguments tells this input stream to
615 * allow that many bytes to be read before the mark position gets
616 * invalidated.
617 *
618 * <p> The general contract of <code>mark</code> is that, if the method
619 * <code>markSupported</code> returns <code>true</code>, the stream somehow
620 * remembers all the bytes read after the call to <code>mark</code> and
621 * stands ready to supply those same bytes again if and whenever the method
622 * <code>reset</code> is called. However, the stream is not required to
623 * remember any data at all if more than <code>readlimit</code> bytes are
624 * read from the stream before <code>reset</code> is called.
625 *
626 * <p> Marking a closed stream should not have any effect on the stream.
627 *
628 * <p> The <code>mark</code> method of <code>InputStream</code> does
629 * nothing.
630 *
631 * @param readlimit the maximum limit of bytes that can be read before
632 * the mark position becomes invalid.
633 * @see java.io.InputStream#reset()
634 */
635 public synchronized void mark(int readlimit) {}
636
637 /**
638 * Repositions this stream to the position at the time the
639 * <code>mark</code> method was last called on this input stream.
640 *
641 * <p> The general contract of <code>reset</code> is:
642 *
643 * <ul>
644 * <li> If the method <code>markSupported</code> returns
645 * <code>true</code>, then:
646 *
647 * <ul><li> If the method <code>mark</code> has not been called since
648 * the stream was created, or the number of bytes read from the stream
649 * since <code>mark</code> was last called is larger than the argument
650 * to <code>mark</code> at that last call, then an
651 * <code>IOException</code> might be thrown.
652 *
653 * <li> If such an <code>IOException</code> is not thrown, then the
654 * stream is reset to a state such that all the bytes read since the
655 * most recent call to <code>mark</code> (or since the start of the
656 * file, if <code>mark</code> has not been called) will be resupplied
657 * to subsequent callers of the <code>read</code> method, followed by
658 * any bytes that otherwise would have been the next input data as of
659 * the time of the call to <code>reset</code>. </ul>
660 *
661 * <li> If the method <code>markSupported</code> returns
662 * <code>false</code>, then:
663 *
664 * <ul><li> The call to <code>reset</code> may throw an
665 * <code>IOException</code>.
666 *
667 * <li> If an <code>IOException</code> is not thrown, then the stream
668 * is reset to a fixed state that depends on the particular type of the
669 * input stream and how it was created. The bytes that will be supplied
670 * to subsequent callers of the <code>read</code> method depend on the
671 * particular type of the input stream. </ul></ul>
672 *
673 * <p>The method <code>reset</code> for class <code>InputStream</code>
674 * does nothing except throw an <code>IOException</code>.
675 *
676 * @exception IOException if this stream has not been marked or if the
677 * mark has been invalidated.
678 * @see java.io.InputStream#mark(int)
679 * @see java.io.IOException
680 */
681 public synchronized void reset() throws IOException {
682 throw new IOException("mark/reset not supported");
683 }
684
685 /**
686 * Tests if this input stream supports the <code>mark</code> and
687 * <code>reset</code> methods. Whether or not <code>mark</code> and
688 * <code>reset</code> are supported is an invariant property of a
689 * particular input stream instance. The <code>markSupported</code> method
690 * of <code>InputStream</code> returns <code>false</code>.
691 *
692 * @return <code>true</code> if this stream instance supports the mark
693 * and reset methods; <code>false</code> otherwise.
694 * @see java.io.InputStream#mark(int)
695 * @see java.io.InputStream#reset()
696 */
697 public boolean markSupported() {
698 return false;
699 }
700
701 /**
702 * Reads all bytes from this input stream and writes the bytes to the
703 * given output stream in the order that they are read. On return, this
704 * input stream will be at end of stream. This method does not close either
705 * stream.
706 * <p>
707 * This method may block indefinitely reading from the input stream, or
708 * writing to the output stream. The behavior for the case where the input
709 * and/or output stream is <i>asynchronously closed</i>, or the thread
710 * interrupted during the transfer, is highly input and output stream
711 * specific, and therefore not specified.
712 * <p>
713 * If an I/O error occurs reading from the input stream or writing to the
714 * output stream, then it may do so after some bytes have been read or
715 * written. Consequently the input stream may not be at end of stream and
716 * one, or both, streams may be in an inconsistent state. It is strongly
717 * recommended that both streams be promptly closed if an I/O error occurs.
718 *
719 * @param out the output stream, non-null
720 * @return the number of bytes transferred
721 * @throws IOException if an I/O error occurs when reading or writing
722 * @throws NullPointerException if {@code out} is {@code null}
723 *
724 * @since 9
725 */
726 public long transferTo(OutputStream out) throws IOException {
727 Objects.requireNonNull(out, "out");
728 long transferred = 0;
729 byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
730 int read;
731 while ((read = this.read(buffer, 0, DEFAULT_BUFFER_SIZE)) >= 0) {
732 out.write(buffer, 0, read);
733 transferred += read;
734 }
735 return transferred;
736 }
737 }