J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2006 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 | import java.nio.charset.Charset; |
| 29 | import java.nio.charset.CharsetEncoder; |
| 30 | import sun.nio.cs.StreamEncoder; |
| 31 | |
| 32 | |
| 33 | /** |
| 34 | * An OutputStreamWriter is a bridge from character streams to byte streams: |
| 35 | * Characters written to it are encoded into bytes using a specified {@link |
| 36 | * java.nio.charset.Charset <code>charset</code>}. The charset that it uses |
| 37 | * may be specified by name or may be given explicitly, or the platform's |
| 38 | * default charset may be accepted. |
| 39 | * |
| 40 | * <p> Each invocation of a write() method causes the encoding converter to be |
| 41 | * invoked on the given character(s). The resulting bytes are accumulated in a |
| 42 | * buffer before being written to the underlying output stream. The size of |
| 43 | * this buffer may be specified, but by default it is large enough for most |
| 44 | * purposes. Note that the characters passed to the write() methods are not |
| 45 | * buffered. |
| 46 | * |
| 47 | * <p> For top efficiency, consider wrapping an OutputStreamWriter within a |
| 48 | * BufferedWriter so as to avoid frequent converter invocations. For example: |
| 49 | * |
| 50 | * <pre> |
| 51 | * Writer out |
| 52 | * = new BufferedWriter(new OutputStreamWriter(System.out)); |
| 53 | * </pre> |
| 54 | * |
| 55 | * <p> A <i>surrogate pair</i> is a character represented by a sequence of two |
| 56 | * <tt>char</tt> values: A <i>high</i> surrogate in the range '\uD800' to |
| 57 | * '\uDBFF' followed by a <i>low</i> surrogate in the range '\uDC00' to |
| 58 | * '\uDFFF'. |
| 59 | * |
| 60 | * <p> A <i>malformed surrogate element</i> is a high surrogate that is not |
| 61 | * followed by a low surrogate or a low surrogate that is not preceded by a |
| 62 | * high surrogate. |
| 63 | * |
| 64 | * <p> This class always replaces malformed surrogate elements and unmappable |
| 65 | * character sequences with the charset's default <i>substitution sequence</i>. |
| 66 | * The {@linkplain java.nio.charset.CharsetEncoder} class should be used when more |
| 67 | * control over the encoding process is required. |
| 68 | * |
| 69 | * @see BufferedWriter |
| 70 | * @see OutputStream |
| 71 | * @see java.nio.charset.Charset |
| 72 | * |
| 73 | * @author Mark Reinhold |
| 74 | * @since JDK1.1 |
| 75 | */ |
| 76 | |
| 77 | public class OutputStreamWriter extends Writer { |
| 78 | |
| 79 | private final StreamEncoder se; |
| 80 | |
| 81 | /** |
| 82 | * Creates an OutputStreamWriter that uses the named charset. |
| 83 | * |
| 84 | * @param out |
| 85 | * An OutputStream |
| 86 | * |
| 87 | * @param charsetName |
| 88 | * The name of a supported |
| 89 | * {@link java.nio.charset.Charset </code>charset<code>} |
| 90 | * |
| 91 | * @exception UnsupportedEncodingException |
| 92 | * If the named encoding is not supported |
| 93 | */ |
| 94 | public OutputStreamWriter(OutputStream out, String charsetName) |
| 95 | throws UnsupportedEncodingException |
| 96 | { |
| 97 | super(out); |
| 98 | if (charsetName == null) |
| 99 | throw new NullPointerException("charsetName"); |
| 100 | se = StreamEncoder.forOutputStreamWriter(out, this, charsetName); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Creates an OutputStreamWriter that uses the default character encoding. |
| 105 | * |
| 106 | * @param out An OutputStream |
| 107 | */ |
| 108 | public OutputStreamWriter(OutputStream out) { |
| 109 | super(out); |
| 110 | try { |
| 111 | se = StreamEncoder.forOutputStreamWriter(out, this, (String)null); |
| 112 | } catch (UnsupportedEncodingException e) { |
| 113 | throw new Error(e); |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Creates an OutputStreamWriter that uses the given charset. </p> |
| 119 | * |
| 120 | * @param out |
| 121 | * An OutputStream |
| 122 | * |
| 123 | * @param cs |
| 124 | * A charset |
| 125 | * |
| 126 | * @since 1.4 |
| 127 | * @spec JSR-51 |
| 128 | */ |
| 129 | public OutputStreamWriter(OutputStream out, Charset cs) { |
| 130 | super(out); |
| 131 | if (cs == null) |
| 132 | throw new NullPointerException("charset"); |
| 133 | se = StreamEncoder.forOutputStreamWriter(out, this, cs); |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * Creates an OutputStreamWriter that uses the given charset encoder. </p> |
| 138 | * |
| 139 | * @param out |
| 140 | * An OutputStream |
| 141 | * |
| 142 | * @param enc |
| 143 | * A charset encoder |
| 144 | * |
| 145 | * @since 1.4 |
| 146 | * @spec JSR-51 |
| 147 | */ |
| 148 | public OutputStreamWriter(OutputStream out, CharsetEncoder enc) { |
| 149 | super(out); |
| 150 | if (enc == null) |
| 151 | throw new NullPointerException("charset encoder"); |
| 152 | se = StreamEncoder.forOutputStreamWriter(out, this, enc); |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Returns the name of the character encoding being used by this stream. |
| 157 | * |
| 158 | * <p> If the encoding has an historical name then that name is returned; |
| 159 | * otherwise the encoding's canonical name is returned. |
| 160 | * |
| 161 | * <p> If this instance was created with the {@link |
| 162 | * #OutputStreamWriter(OutputStream, String)} constructor then the returned |
| 163 | * name, being unique for the encoding, may differ from the name passed to |
| 164 | * the constructor. This method may return <tt>null</tt> if the stream has |
| 165 | * been closed. </p> |
| 166 | * |
| 167 | * @return The historical name of this encoding, or possibly |
| 168 | * <code>null</code> if the stream has been closed |
| 169 | * |
| 170 | * @see java.nio.charset.Charset |
| 171 | * |
| 172 | * @revised 1.4 |
| 173 | * @spec JSR-51 |
| 174 | */ |
| 175 | public String getEncoding() { |
| 176 | return se.getEncoding(); |
| 177 | } |
| 178 | |
| 179 | /** |
| 180 | * Flushes the output buffer to the underlying byte stream, without flushing |
| 181 | * the byte stream itself. This method is non-private only so that it may |
| 182 | * be invoked by PrintStream. |
| 183 | */ |
| 184 | void flushBuffer() throws IOException { |
| 185 | se.flushBuffer(); |
| 186 | } |
| 187 | |
| 188 | /** |
| 189 | * Writes a single character. |
| 190 | * |
| 191 | * @exception IOException If an I/O error occurs |
| 192 | */ |
| 193 | public void write(int c) throws IOException { |
| 194 | se.write(c); |
| 195 | } |
| 196 | |
| 197 | /** |
| 198 | * Writes a portion of an array of characters. |
| 199 | * |
| 200 | * @param cbuf Buffer of characters |
| 201 | * @param off Offset from which to start writing characters |
| 202 | * @param len Number of characters to write |
| 203 | * |
| 204 | * @exception IOException If an I/O error occurs |
| 205 | */ |
| 206 | public void write(char cbuf[], int off, int len) throws IOException { |
| 207 | se.write(cbuf, off, len); |
| 208 | } |
| 209 | |
| 210 | /** |
| 211 | * Writes a portion of a string. |
| 212 | * |
| 213 | * @param str A String |
| 214 | * @param off Offset from which to start writing characters |
| 215 | * @param len Number of characters to write |
| 216 | * |
| 217 | * @exception IOException If an I/O error occurs |
| 218 | */ |
| 219 | public void write(String str, int off, int len) throws IOException { |
| 220 | se.write(str, off, len); |
| 221 | } |
| 222 | |
| 223 | /** |
| 224 | * Flushes the stream. |
| 225 | * |
| 226 | * @exception IOException If an I/O error occurs |
| 227 | */ |
| 228 | public void flush() throws IOException { |
| 229 | se.flush(); |
| 230 | } |
| 231 | |
| 232 | public void close() throws IOException { |
| 233 | se.close(); |
| 234 | } |
| 235 | } |