View Javadoc
1   /*
2    * Copyright (c) 1994, 2004, 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  /**
29   * This abstract class is the superclass of all classes representing
30   * an output stream of bytes. An output stream accepts output bytes
31   * and sends them to some sink.
32   * <p>
33   * Applications that need to define a subclass of
34   * <code>OutputStream</code> must always provide at least a method
35   * that writes one byte of output.
36   *
37   * @author  Arthur van Hoff
38   * @see     java.io.BufferedOutputStream
39   * @see     java.io.ByteArrayOutputStream
40   * @see     java.io.DataOutputStream
41   * @see     java.io.FilterOutputStream
42   * @see     java.io.InputStream
43   * @see     java.io.OutputStream#write(int)
44   * @since   JDK1.0
45   */
46  public abstract class OutputStream implements Closeable, Flushable {
47      /**
48       * Writes the specified byte to this output stream. The general
49       * contract for <code>write</code> is that one byte is written
50       * to the output stream. The byte to be written is the eight
51       * low-order bits of the argument <code>b</code>. The 24
52       * high-order bits of <code>b</code> are ignored.
53       * <p>
54       * Subclasses of <code>OutputStream</code> must provide an
55       * implementation for this method.
56       *
57       * @param      b   the <code>byte</code>.
58       * @exception  IOException  if an I/O error occurs. In particular,
59       *             an <code>IOException</code> may be thrown if the
60       *             output stream has been closed.
61       */
62      public abstract void write(int b) throws IOException;
63  
64      /**
65       * Writes <code>b.length</code> bytes from the specified byte array
66       * to this output stream. The general contract for <code>write(b)</code>
67       * is that it should have exactly the same effect as the call
68       * <code>write(b, 0, b.length)</code>.
69       *
70       * @param      b   the data.
71       * @exception  IOException  if an I/O error occurs.
72       * @see        java.io.OutputStream#write(byte[], int, int)
73       */
74      public void write(byte b[]) throws IOException {
75          write(b, 0, b.length);
76      }
77  
78      /**
79       * Writes <code>len</code> bytes from the specified byte array
80       * starting at offset <code>off</code> to this output stream.
81       * The general contract for <code>write(b, off, len)</code> is that
82       * some of the bytes in the array <code>b</code> are written to the
83       * output stream in order; element <code>b[off]</code> is the first
84       * byte written and <code>b[off+len-1]</code> is the last byte written
85       * by this operation.
86       * <p>
87       * The <code>write</code> method of <code>OutputStream</code> calls
88       * the write method of one argument on each of the bytes to be
89       * written out. Subclasses are encouraged to override this method and
90       * provide a more efficient implementation.
91       * <p>
92       * If <code>b</code> is <code>null</code>, a
93       * <code>NullPointerException</code> is thrown.
94       * <p>
95       * If <code>off</code> is negative, or <code>len</code> is negative, or
96       * <code>off+len</code> is greater than the length of the array
97       * <code>b</code>, then an <tt>IndexOutOfBoundsException</tt> is thrown.
98       *
99       * @param      b     the data.
100      * @param      off   the start offset in the data.
101      * @param      len   the number of bytes to write.
102      * @exception  IOException  if an I/O error occurs. In particular,
103      *             an <code>IOException</code> is thrown if the output
104      *             stream is closed.
105      */
106     public void write(byte b[], int off, int len) throws IOException {
107         if (b == null) {
108             throw new NullPointerException();
109         } else if ((off < 0) || (off > b.length) || (len < 0) ||
110                    ((off + len) > b.length) || ((off + len) < 0)) {
111             throw new IndexOutOfBoundsException();
112         } else if (len == 0) {
113             return;
114         }
115         for (int i = 0 ; i < len ; i++) {
116             write(b[off + i]);
117         }
118     }
119 
120     /**
121      * Flushes this output stream and forces any buffered output bytes
122      * to be written out. The general contract of <code>flush</code> is
123      * that calling it is an indication that, if any bytes previously
124      * written have been buffered by the implementation of the output
125      * stream, such bytes should immediately be written to their
126      * intended destination.
127      * <p>
128      * If the intended destination of this stream is an abstraction provided by
129      * the underlying operating system, for example a file, then flushing the
130      * stream guarantees only that bytes previously written to the stream are
131      * passed to the operating system for writing; it does not guarantee that
132      * they are actually written to a physical device such as a disk drive.
133      * <p>
134      * The <code>flush</code> method of <code>OutputStream</code> does nothing.
135      *
136      * @exception  IOException  if an I/O error occurs.
137      */
138     public void flush() throws IOException {
139     }
140 
141     /**
142      * Closes this output stream and releases any system resources
143      * associated with this stream. The general contract of <code>close</code>
144      * is that it closes the output stream. A closed stream cannot perform
145      * output operations and cannot be reopened.
146      * <p>
147      * The <code>close</code> method of <code>OutputStream</code> does nothing.
148      *
149      * @exception  IOException  if an I/O error occurs.
150      */
151     public void close() throws IOException {
152     }
153 
154 }