2
|
1 |
/*
|
5506
|
2 |
* Copyright (c) 2000, 2001, Oracle and/or its affiliates. All rights reserved.
|
2
|
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
|
5506
|
7 |
* published by the Free Software Foundation. Oracle designates this
|
2
|
8 |
* particular file as subject to the "Classpath" exception as provided
|
5506
|
9 |
* by Oracle in the LICENSE file that accompanied this code.
|
2
|
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 |
*
|
5506
|
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.
|
2
|
24 |
*/
|
|
25 |
|
|
26 |
package java.nio.channels;
|
|
27 |
|
|
28 |
import java.io.IOException;
|
|
29 |
import java.nio.ByteBuffer;
|
|
30 |
|
|
31 |
|
|
32 |
/**
|
|
33 |
* A channel that can read bytes.
|
|
34 |
*
|
|
35 |
* <p> Only one read operation upon a readable channel may be in progress at
|
|
36 |
* any given time. If one thread initiates a read operation upon a channel
|
|
37 |
* then any other thread that attempts to initiate another read operation will
|
|
38 |
* block until the first operation is complete. Whether or not other kinds of
|
|
39 |
* I/O operations may proceed concurrently with a read operation depends upon
|
|
40 |
* the type of the channel. </p>
|
|
41 |
*
|
|
42 |
*
|
|
43 |
* @author Mark Reinhold
|
|
44 |
* @author JSR-51 Expert Group
|
|
45 |
* @since 1.4
|
|
46 |
*/
|
|
47 |
|
|
48 |
public interface ReadableByteChannel extends Channel {
|
|
49 |
|
|
50 |
/**
|
|
51 |
* Reads a sequence of bytes from this channel into the given buffer.
|
|
52 |
*
|
|
53 |
* <p> An attempt is made to read up to <i>r</i> bytes from the channel,
|
|
54 |
* where <i>r</i> is the number of bytes remaining in the buffer, that is,
|
|
55 |
* <tt>dst.remaining()</tt>, at the moment this method is invoked.
|
|
56 |
*
|
|
57 |
* <p> Suppose that a byte sequence of length <i>n</i> is read, where
|
|
58 |
* <tt>0</tt> <tt><=</tt> <i>n</i> <tt><=</tt> <i>r</i>.
|
|
59 |
* This byte sequence will be transferred into the buffer so that the first
|
|
60 |
* byte in the sequence is at index <i>p</i> and the last byte is at index
|
|
61 |
* <i>p</i> <tt>+</tt> <i>n</i> <tt>-</tt> <tt>1</tt>,
|
|
62 |
* where <i>p</i> is the buffer's position at the moment this method is
|
|
63 |
* invoked. Upon return the buffer's position will be equal to
|
|
64 |
* <i>p</i> <tt>+</tt> <i>n</i>; its limit will not have changed.
|
|
65 |
*
|
|
66 |
* <p> A read operation might not fill the buffer, and in fact it might not
|
|
67 |
* read any bytes at all. Whether or not it does so depends upon the
|
|
68 |
* nature and state of the channel. A socket channel in non-blocking mode,
|
|
69 |
* for example, cannot read any more bytes than are immediately available
|
|
70 |
* from the socket's input buffer; similarly, a file channel cannot read
|
|
71 |
* any more bytes than remain in the file. It is guaranteed, however, that
|
|
72 |
* if a channel is in blocking mode and there is at least one byte
|
|
73 |
* remaining in the buffer then this method will block until at least one
|
|
74 |
* byte is read.
|
|
75 |
*
|
|
76 |
* <p> This method may be invoked at any time. If another thread has
|
|
77 |
* already initiated a read operation upon this channel, however, then an
|
|
78 |
* invocation of this method will block until the first operation is
|
|
79 |
* complete. </p>
|
|
80 |
*
|
|
81 |
* @param dst
|
|
82 |
* The buffer into which bytes are to be transferred
|
|
83 |
*
|
|
84 |
* @return The number of bytes read, possibly zero, or <tt>-1</tt> if the
|
|
85 |
* channel has reached end-of-stream
|
|
86 |
*
|
|
87 |
* @throws NonReadableChannelException
|
|
88 |
* If this channel was not opened for reading
|
|
89 |
*
|
|
90 |
* @throws ClosedChannelException
|
|
91 |
* If this channel is closed
|
|
92 |
*
|
|
93 |
* @throws AsynchronousCloseException
|
|
94 |
* If another thread closes this channel
|
|
95 |
* while the read operation is in progress
|
|
96 |
*
|
|
97 |
* @throws ClosedByInterruptException
|
|
98 |
* If another thread interrupts the current thread
|
|
99 |
* while the read operation is in progress, thereby
|
|
100 |
* closing the channel and setting the current thread's
|
|
101 |
* interrupt status
|
|
102 |
*
|
|
103 |
* @throws IOException
|
|
104 |
* If some other I/O error occurs
|
|
105 |
*/
|
|
106 |
public int read(ByteBuffer dst) throws IOException;
|
|
107 |
|
|
108 |
}
|