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 }