J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1994-1999 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.io; |
| 27 | |
| 28 | /** |
| 29 | * This class is the superclass of all classes that filter output |
| 30 | * streams. These streams sit on top of an already existing output |
| 31 | * stream (the <i>underlying</i> output stream) which it uses as its |
| 32 | * basic sink of data, but possibly transforming the data along the |
| 33 | * way or providing additional functionality. |
| 34 | * <p> |
| 35 | * The class <code>FilterOutputStream</code> itself simply overrides |
| 36 | * all methods of <code>OutputStream</code> with versions that pass |
| 37 | * all requests to the underlying output stream. Subclasses of |
| 38 | * <code>FilterOutputStream</code> may further override some of these |
| 39 | * methods as well as provide additional methods and fields. |
| 40 | * |
| 41 | * @author Jonathan Payne |
| 42 | * @since JDK1.0 |
| 43 | */ |
| 44 | public |
| 45 | class FilterOutputStream extends OutputStream { |
| 46 | /** |
| 47 | * The underlying output stream to be filtered. |
| 48 | */ |
| 49 | protected OutputStream out; |
| 50 | |
| 51 | /** |
| 52 | * Creates an output stream filter built on top of the specified |
| 53 | * underlying output stream. |
| 54 | * |
| 55 | * @param out the underlying output stream to be assigned to |
| 56 | * the field <tt>this.out</tt> for later use, or |
| 57 | * <code>null</code> if this instance is to be |
| 58 | * created without an underlying stream. |
| 59 | */ |
| 60 | public FilterOutputStream(OutputStream out) { |
| 61 | this.out = out; |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Writes the specified <code>byte</code> to this output stream. |
| 66 | * <p> |
| 67 | * The <code>write</code> method of <code>FilterOutputStream</code> |
| 68 | * calls the <code>write</code> method of its underlying output stream, |
| 69 | * that is, it performs <tt>out.write(b)</tt>. |
| 70 | * <p> |
| 71 | * Implements the abstract <tt>write</tt> method of <tt>OutputStream</tt>. |
| 72 | * |
| 73 | * @param b the <code>byte</code>. |
| 74 | * @exception IOException if an I/O error occurs. |
| 75 | */ |
| 76 | public void write(int b) throws IOException { |
| 77 | out.write(b); |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Writes <code>b.length</code> bytes to this output stream. |
| 82 | * <p> |
| 83 | * The <code>write</code> method of <code>FilterOutputStream</code> |
| 84 | * calls its <code>write</code> method of three arguments with the |
| 85 | * arguments <code>b</code>, <code>0</code>, and |
| 86 | * <code>b.length</code>. |
| 87 | * <p> |
| 88 | * Note that this method does not call the one-argument |
| 89 | * <code>write</code> method of its underlying stream with the single |
| 90 | * argument <code>b</code>. |
| 91 | * |
| 92 | * @param b the data to be written. |
| 93 | * @exception IOException if an I/O error occurs. |
| 94 | * @see java.io.FilterOutputStream#write(byte[], int, int) |
| 95 | */ |
| 96 | public void write(byte b[]) throws IOException { |
| 97 | write(b, 0, b.length); |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Writes <code>len</code> bytes from the specified |
| 102 | * <code>byte</code> array starting at offset <code>off</code> to |
| 103 | * this output stream. |
| 104 | * <p> |
| 105 | * The <code>write</code> method of <code>FilterOutputStream</code> |
| 106 | * calls the <code>write</code> method of one argument on each |
| 107 | * <code>byte</code> to output. |
| 108 | * <p> |
| 109 | * Note that this method does not call the <code>write</code> method |
| 110 | * of its underlying input stream with the same arguments. Subclasses |
| 111 | * of <code>FilterOutputStream</code> should provide a more efficient |
| 112 | * implementation of this method. |
| 113 | * |
| 114 | * @param b the data. |
| 115 | * @param off the start offset in the data. |
| 116 | * @param len the number of bytes to write. |
| 117 | * @exception IOException if an I/O error occurs. |
| 118 | * @see java.io.FilterOutputStream#write(int) |
| 119 | */ |
| 120 | public void write(byte b[], int off, int len) throws IOException { |
| 121 | if ((off | len | (b.length - (len + off)) | (off + len)) < 0) |
| 122 | throw new IndexOutOfBoundsException(); |
| 123 | |
| 124 | for (int i = 0 ; i < len ; i++) { |
| 125 | write(b[off + i]); |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Flushes this output stream and forces any buffered output bytes |
| 131 | * to be written out to the stream. |
| 132 | * <p> |
| 133 | * The <code>flush</code> method of <code>FilterOutputStream</code> |
| 134 | * calls the <code>flush</code> method of its underlying output stream. |
| 135 | * |
| 136 | * @exception IOException if an I/O error occurs. |
| 137 | * @see java.io.FilterOutputStream#out |
| 138 | */ |
| 139 | public void flush() throws IOException { |
| 140 | out.flush(); |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Closes this output stream and releases any system resources |
| 145 | * associated with the stream. |
| 146 | * <p> |
| 147 | * The <code>close</code> method of <code>FilterOutputStream</code> |
| 148 | * calls its <code>flush</code> method, and then calls the |
| 149 | * <code>close</code> method of its underlying output stream. |
| 150 | * |
| 151 | * @exception IOException if an I/O error occurs. |
| 152 | * @see java.io.FilterOutputStream#flush() |
| 153 | * @see java.io.FilterOutputStream#out |
| 154 | */ |
| 155 | public void close() throws IOException { |
| 156 | try { |
| 157 | flush(); |
| 158 | } catch (IOException ignored) { |
| 159 | } |
| 160 | out.close(); |
| 161 | } |
| 162 | } |