1 /*
2 * Copyright (c) 1994, 2017, 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.Objects;
29
30 /**
31 * This abstract class is the superclass of all classes representing
32 * an output stream of bytes. An output stream accepts output bytes
33 * and sends them to some sink.
34 * <p>
35 * Applications that need to define a subclass of
36 * <code>OutputStream</code> must always provide at least a method
37 * that writes one byte of output.
38 *
39 * @author Arthur van Hoff
40 * @see java.io.BufferedOutputStream
41 * @see java.io.ByteArrayOutputStream
42 * @see java.io.DataOutputStream
43 * @see java.io.FilterOutputStream
44 * @see java.io.InputStream
45 * @see java.io.OutputStream#write(int)
46 * @since 1.0
47 */
48 public abstract class OutputStream implements Closeable, Flushable {
49 /**
50 * Writes the specified byte to this output stream. The general
51 * contract for <code>write</code> is that one byte is written
52 * to the output stream. The byte to be written is the eight
53 * low-order bits of the argument <code>b</code>. The 24
54 * high-order bits of <code>b</code> are ignored.
55 * <p>
56 * Subclasses of <code>OutputStream</code> must provide an
57 * implementation for this method.
58 *
59 * @param b the <code>byte</code>.
60 * @exception IOException if an I/O error occurs. In particular,
61 * an <code>IOException</code> may be thrown if the
62 * output stream has been closed.
63 */
64 public abstract void write(int b) throws IOException;
65
66 /**
67 * Writes <code>b.length</code> bytes from the specified byte array
68 * to this output stream. The general contract for <code>write(b)</code>
69 * is that it should have exactly the same effect as the call
70 * <code>write(b, 0, b.length)</code>.
71 *
72 * @param b the data.
73 * @exception IOException if an I/O error occurs.
74 * @see java.io.OutputStream#write(byte[], int, int)
75 */
76 public void write(byte b[]) throws IOException {
77 write(b, 0, b.length);
78 }
79
80 /**
81 * Writes <code>len</code> bytes from the specified byte array
82 * starting at offset <code>off</code> to this output stream.
83 * The general contract for <code>write(b, off, len)</code> is that
84 * some of the bytes in the array <code>b</code> are written to the
85 * output stream in order; element <code>b[off]</code> is the first
86 * byte written and <code>b[off+len-1]</code> is the last byte written
87 * by this operation.
88 * <p>
89 * The <code>write</code> method of <code>OutputStream</code> calls
90 * the write method of one argument on each of the bytes to be
91 * written out. Subclasses are encouraged to override this method and
92 * provide a more efficient implementation.
93 * <p>
94 * If <code>b</code> is <code>null</code>, a
95 * <code>NullPointerException</code> is thrown.
96 * <p>
97 * If <code>off</code> is negative, or <code>len</code> is negative, or
98 * <code>off+len</code> is greater than the length of the array
99 * {@code b}, then an {@code IndexOutOfBoundsException} is thrown.
100 *
101 * @param b the data.
102 * @param off the start offset in the data.
103 * @param len the number of bytes to write.
104 * @exception IOException if an I/O error occurs. In particular,
105 * an <code>IOException</code> is thrown if the output
106 * stream is closed.
107 */
108 public void write(byte b[], int off, int len) throws IOException {
109 Objects.requireNonNull(b);
110 Objects.checkFromIndexSize(off, len, b.length);
111 // len == 0 condition implicitly handled by loop bounds
112 for (int i = 0 ; i < len ; i++) {
113 write(b[off + i]);
114 }
115 }
116
117 /**
118 * Flushes this output stream and forces any buffered output bytes
119 * to be written out. The general contract of <code>flush</code> is
120 * that calling it is an indication that, if any bytes previously
121 * written have been buffered by the implementation of the output
122 * stream, such bytes should immediately be written to their
123 * intended destination.
124 * <p>
125 * If the intended destination of this stream is an abstraction provided by
126 * the underlying operating system, for example a file, then flushing the
127 * stream guarantees only that bytes previously written to the stream are
128 * passed to the operating system for writing; it does not guarantee that
129 * they are actually written to a physical device such as a disk drive.
130 * <p>
131 * The <code>flush</code> method of <code>OutputStream</code> does nothing.
132 *
133 * @exception IOException if an I/O error occurs.
134 */
135 public void flush() throws IOException {
136 }
137
138 /**
139 * Closes this output stream and releases any system resources
140 * associated with this stream. The general contract of <code>close</code>
141 * is that it closes the output stream. A closed stream cannot perform
142 * output operations and cannot be reopened.
143 * <p>
144 * The <code>close</code> method of <code>OutputStream</code> does nothing.
145 *
146 * @exception IOException if an I/O error occurs.
147 */
148 public void close() throws IOException {
149 }
150
151 }