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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2005, 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.nio.charset.Charset; | ||
| 29 | import java.nio.charset.CharsetDecoder; | ||
| 30 | import sun.nio.cs.StreamDecoder; | ||
| 31 | |||
| 32 | |||
| 33 | /** | ||
| 34 | * An InputStreamReader is a bridge from byte streams to character streams: It | ||
| 35 | * reads bytes and decodes them into characters 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 one of an InputStreamReader's read() methods may | ||
| 41 | * cause one or more bytes to be read from the underlying byte-input stream. | ||
| 42 | * To enable the efficient conversion of bytes to characters, more bytes may | ||
| 43 | * be read ahead from the underlying stream than are necessary to satisfy the | ||
| 44 | * current read operation. | ||
| 45 | * | ||
| 46 | * <p> For top efficiency, consider wrapping an InputStreamReader within a | ||
| 47 | * BufferedReader. For example: | ||
| 48 | * | ||
| 49 | * <pre> | ||
| 50 | * BufferedReader in | ||
| 51 | * = new BufferedReader(new InputStreamReader(System.in)); | ||
| 52 | * </pre> | ||
| 53 | * | ||
| 54 | * @see BufferedReader | ||
| 55 | * @see InputStream | ||
| 56 | * @see java.nio.charset.Charset | ||
| 57 | * | ||
| 58 | * @author Mark Reinhold | ||
| 59 | * @since JDK1.1 | ||
| 60 | */ | ||
| 61 | |||
| 62 | public class InputStreamReader extends Reader { | ||
| 63 | |||
| 64 | private final StreamDecoder sd; | ||
| 65 | |||
| 66 | /** | ||
| 67 | * Creates an InputStreamReader that uses the default charset. | ||
| 68 | * | ||
| 69 | * @param in An InputStream | ||
| 70 | */ | ||
| 71 | public InputStreamReader(InputStream in) { | ||
| 72 | super(in); | ||
| 73 | try { | ||
| 74 | sd = StreamDecoder.forInputStreamReader(in, this, (String)null); // ## check lock object | ||
| 75 | } catch (UnsupportedEncodingException e) { | ||
| 76 | // The default encoding should always be available | ||
| 77 | throw new Error(e); | ||
| 78 | } | ||
| 79 | } | ||
| 80 | |||
| 81 | /** | ||
| 82 | * Creates an InputStreamReader that uses the named charset. | ||
| 83 | * | ||
| 84 | * @param in | ||
| 85 | * An InputStream | ||
| 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 charset is not supported | ||
| 93 | */ | ||
| 94 | public InputStreamReader(InputStream in, String charsetName) | ||
| 95 | throws UnsupportedEncodingException | ||
| 96 | { | ||
| 97 | super(in); | ||
| 98 | if (charsetName == null) | ||
| 99 | throw new NullPointerException("charsetName"); | ||
| 100 | sd = StreamDecoder.forInputStreamReader(in, this, charsetName); | ||
| 101 | } | ||
| 102 | |||
| 103 | /** | ||
| 104 | * Creates an InputStreamReader that uses the given charset. </p> | ||
| 105 | * | ||
| 106 | * @param in An InputStream | ||
| 107 | * @param cs A charset | ||
| 108 | * | ||
| 109 | * @since 1.4 | ||
| 110 | * @spec JSR-51 | ||
| 111 | */ | ||
| 112 | public InputStreamReader(InputStream in, Charset cs) { | ||
| 113 | super(in); | ||
| 114 | if (cs == null) | ||
| 115 | throw new NullPointerException("charset"); | ||
| 116 | sd = StreamDecoder.forInputStreamReader(in, this, cs); | ||
| 117 | } | ||
| 118 | |||
| 119 | /** | ||
| 120 | * Creates an InputStreamReader that uses the given charset decoder. </p> | ||
| 121 | * | ||
| 122 | * @param in An InputStream | ||
| 123 | * @param dec A charset decoder | ||
| 124 | * | ||
| 125 | * @since 1.4 | ||
| 126 | * @spec JSR-51 | ||
| 127 | */ | ||
| 128 | public InputStreamReader(InputStream in, CharsetDecoder dec) { | ||
| 129 | super(in); | ||
| 130 | if (dec == null) | ||
| 131 | throw new NullPointerException("charset decoder"); | ||
| 132 | sd = StreamDecoder.forInputStreamReader(in, this, dec); | ||
| 133 | } | ||
| 134 | |||
| 135 | /** | ||
| 136 | * Returns the name of the character encoding being used by this stream. | ||
| 137 | * | ||
| 138 | * <p> If the encoding has an historical name then that name is returned; | ||
| 139 | * otherwise the encoding's canonical name is returned. | ||
| 140 | * | ||
| 141 | * <p> If this instance was created with the {@link | ||
| 142 | * #InputStreamReader(InputStream, String)} constructor then the returned | ||
| 143 | * name, being unique for the encoding, may differ from the name passed to | ||
| 144 | * the constructor. This method will return <code>null</code> if the | ||
| 145 | * stream has been closed. | ||
| 146 | * </p> | ||
| 147 | * @return The historical name of this encoding, or | ||
| 148 | * <code>null</code> if the stream has been closed | ||
| 149 | * | ||
| 150 | * @see java.nio.charset.Charset | ||
| 151 | * | ||
| 152 | * @revised 1.4 | ||
| 153 | * @spec JSR-51 | ||
| 154 | */ | ||
| 155 | public String getEncoding() { | ||
| 156 | return sd.getEncoding(); | ||
| 157 | } | ||
| 158 | |||
| 159 | /** | ||
| 160 | * Reads a single character. | ||
| 161 | * | ||
| 162 | * @return The character read, or -1 if the end of the stream has been | ||
| 163 | * reached | ||
| 164 | * | ||
| 165 | * @exception IOException If an I/O error occurs | ||
| 166 | */ | ||
| 167 | public int read() throws IOException { | ||
| 168 | return sd.read(); | ||
| 169 | } | ||
| 170 | |||
| 171 | /** | ||
| 172 | * Reads characters into a portion of an array. | ||
| 173 | * | ||
| 174 | * @param cbuf Destination buffer | ||
| 175 | * @param offset Offset at which to start storing characters | ||
| 176 | * @param length Maximum number of characters to read | ||
| 177 | * | ||
| 178 | * @return The number of characters read, or -1 if the end of the | ||
| 179 | * stream has been reached | ||
| 180 | * | ||
| 181 | * @exception IOException If an I/O error occurs | ||
| 182 | */ | ||
| 183 | public int read(char cbuf[], int offset, int length) throws IOException { | ||
| 184 | return sd.read(cbuf, offset, length); | ||
| 185 | } | ||
| 186 | |||
| 187 | /** | ||
| 188 | * Tells whether this stream is ready to be read. An InputStreamReader is | ||
| 189 | * ready if its input buffer is not empty, or if bytes are available to be | ||
| 190 | * read from the underlying byte stream. | ||
| 191 | * | ||
| 192 | * @exception IOException If an I/O error occurs | ||
| 193 | */ | ||
| 194 | public boolean ready() throws IOException { | ||
| 195 | return sd.ready(); | ||
| 196 | } | ||
| 197 | |||
| 198 | public void close() throws IOException { | ||
| 199 | sd.close(); | ||
| 200 | } | ||
| 201 | } | ||