J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2006 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 | /** |
| 29 | * The <code>DataOutput</code> interface provides |
| 30 | * for converting data from any of the Java |
| 31 | * primitive types to a series of bytes and |
| 32 | * writing these bytes to a binary stream. |
| 33 | * There is also a facility for converting |
| 34 | * a <code>String</code> into |
| 35 | * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> |
| 36 | * format and writing the resulting series |
| 37 | * of bytes. |
| 38 | * <p> |
| 39 | * For all the methods in this interface that |
| 40 | * write bytes, it is generally true that if |
| 41 | * a byte cannot be written for any reason, |
| 42 | * an <code>IOException</code> is thrown. |
| 43 | * |
| 44 | * @author Frank Yellin |
| 45 | * @see java.io.DataInput |
| 46 | * @see java.io.DataOutputStream |
| 47 | * @since JDK1.0 |
| 48 | */ |
| 49 | public |
| 50 | interface DataOutput { |
| 51 | /** |
| 52 | * Writes to the output stream the eight |
| 53 | * low-order bits of the argument <code>b</code>. |
| 54 | * The 24 high-order bits of <code>b</code> |
| 55 | * are ignored. |
| 56 | * |
| 57 | * @param b the byte to be written. |
| 58 | * @throws IOException if an I/O error occurs. |
| 59 | */ |
| 60 | void write(int b) throws IOException; |
| 61 | |
| 62 | /** |
| 63 | * Writes to the output stream all the bytes in array <code>b</code>. |
| 64 | * If <code>b</code> is <code>null</code>, |
| 65 | * a <code>NullPointerException</code> is thrown. |
| 66 | * If <code>b.length</code> is zero, then |
| 67 | * no bytes are written. Otherwise, the byte |
| 68 | * <code>b[0]</code> is written first, then |
| 69 | * <code>b[1]</code>, and so on; the last byte |
| 70 | * written is <code>b[b.length-1]</code>. |
| 71 | * |
| 72 | * @param b the data. |
| 73 | * @throws IOException if an I/O error occurs. |
| 74 | */ |
| 75 | void write(byte b[]) throws IOException; |
| 76 | |
| 77 | /** |
| 78 | * Writes <code>len</code> bytes from array |
| 79 | * <code>b</code>, in order, to |
| 80 | * the output stream. If <code>b</code> |
| 81 | * is <code>null</code>, a <code>NullPointerException</code> |
| 82 | * is thrown. If <code>off</code> is negative, |
| 83 | * or <code>len</code> is negative, or <code>off+len</code> |
| 84 | * is greater than the length of the array |
| 85 | * <code>b</code>, then an <code>IndexOutOfBoundsException</code> |
| 86 | * is thrown. If <code>len</code> is zero, |
| 87 | * then no bytes are written. Otherwise, the |
| 88 | * byte <code>b[off]</code> is written first, |
| 89 | * then <code>b[off+1]</code>, and so on; the |
| 90 | * last byte written is <code>b[off+len-1]</code>. |
| 91 | * |
| 92 | * @param b the data. |
| 93 | * @param off the start offset in the data. |
| 94 | * @param len the number of bytes to write. |
| 95 | * @throws IOException if an I/O error occurs. |
| 96 | */ |
| 97 | void write(byte b[], int off, int len) throws IOException; |
| 98 | |
| 99 | /** |
| 100 | * Writes a <code>boolean</code> value to this output stream. |
| 101 | * If the argument <code>v</code> |
| 102 | * is <code>true</code>, the value <code>(byte)1</code> |
| 103 | * is written; if <code>v</code> is <code>false</code>, |
| 104 | * the value <code>(byte)0</code> is written. |
| 105 | * The byte written by this method may |
| 106 | * be read by the <code>readBoolean</code> |
| 107 | * method of interface <code>DataInput</code>, |
| 108 | * which will then return a <code>boolean</code> |
| 109 | * equal to <code>v</code>. |
| 110 | * |
| 111 | * @param v the boolean to be written. |
| 112 | * @throws IOException if an I/O error occurs. |
| 113 | */ |
| 114 | void writeBoolean(boolean v) throws IOException; |
| 115 | |
| 116 | /** |
| 117 | * Writes to the output stream the eight low- |
| 118 | * order bits of the argument <code>v</code>. |
| 119 | * The 24 high-order bits of <code>v</code> |
| 120 | * are ignored. (This means that <code>writeByte</code> |
| 121 | * does exactly the same thing as <code>write</code> |
| 122 | * for an integer argument.) The byte written |
| 123 | * by this method may be read by the <code>readByte</code> |
| 124 | * method of interface <code>DataInput</code>, |
| 125 | * which will then return a <code>byte</code> |
| 126 | * equal to <code>(byte)v</code>. |
| 127 | * |
| 128 | * @param v the byte value to be written. |
| 129 | * @throws IOException if an I/O error occurs. |
| 130 | */ |
| 131 | void writeByte(int v) throws IOException; |
| 132 | |
| 133 | /** |
| 134 | * Writes two bytes to the output |
| 135 | * stream to represent the value of the argument. |
| 136 | * The byte values to be written, in the order |
| 137 | * shown, are: <p> |
| 138 | * <pre><code> |
| 139 | * (byte)(0xff & (v >> 8)) |
| 140 | * (byte)(0xff & v) |
| 141 | * </code> </pre> <p> |
| 142 | * The bytes written by this method may be |
| 143 | * read by the <code>readShort</code> method |
| 144 | * of interface <code>DataInput</code> , which |
| 145 | * will then return a <code>short</code> equal |
| 146 | * to <code>(short)v</code>. |
| 147 | * |
| 148 | * @param v the <code>short</code> value to be written. |
| 149 | * @throws IOException if an I/O error occurs. |
| 150 | */ |
| 151 | void writeShort(int v) throws IOException; |
| 152 | |
| 153 | /** |
| 154 | * Writes a <code>char</code> value, which |
| 155 | * is comprised of two bytes, to the |
| 156 | * output stream. |
| 157 | * The byte values to be written, in the order |
| 158 | * shown, are: |
| 159 | * <p><pre><code> |
| 160 | * (byte)(0xff & (v >> 8)) |
| 161 | * (byte)(0xff & v) |
| 162 | * </code></pre><p> |
| 163 | * The bytes written by this method may be |
| 164 | * read by the <code>readChar</code> method |
| 165 | * of interface <code>DataInput</code> , which |
| 166 | * will then return a <code>char</code> equal |
| 167 | * to <code>(char)v</code>. |
| 168 | * |
| 169 | * @param v the <code>char</code> value to be written. |
| 170 | * @throws IOException if an I/O error occurs. |
| 171 | */ |
| 172 | void writeChar(int v) throws IOException; |
| 173 | |
| 174 | /** |
| 175 | * Writes an <code>int</code> value, which is |
| 176 | * comprised of four bytes, to the output stream. |
| 177 | * The byte values to be written, in the order |
| 178 | * shown, are: |
| 179 | * <p><pre><code> |
| 180 | * (byte)(0xff & (v >> 24)) |
| 181 | * (byte)(0xff & (v >> 16)) |
| 182 | * (byte)(0xff & (v >>    8)) |
| 183 | * (byte)(0xff & v) |
| 184 | * </code></pre><p> |
| 185 | * The bytes written by this method may be read |
| 186 | * by the <code>readInt</code> method of interface |
| 187 | * <code>DataInput</code> , which will then |
| 188 | * return an <code>int</code> equal to <code>v</code>. |
| 189 | * |
| 190 | * @param v the <code>int</code> value to be written. |
| 191 | * @throws IOException if an I/O error occurs. |
| 192 | */ |
| 193 | void writeInt(int v) throws IOException; |
| 194 | |
| 195 | /** |
| 196 | * Writes a <code>long</code> value, which is |
| 197 | * comprised of eight bytes, to the output stream. |
| 198 | * The byte values to be written, in the order |
| 199 | * shown, are: |
| 200 | * <p><pre><code> |
| 201 | * (byte)(0xff & (v >> 56)) |
| 202 | * (byte)(0xff & (v >> 48)) |
| 203 | * (byte)(0xff & (v >> 40)) |
| 204 | * (byte)(0xff & (v >> 32)) |
| 205 | * (byte)(0xff & (v >> 24)) |
| 206 | * (byte)(0xff & (v >> 16)) |
| 207 | * (byte)(0xff & (v >> 8)) |
| 208 | * (byte)(0xff & v) |
| 209 | * </code></pre><p> |
| 210 | * The bytes written by this method may be |
| 211 | * read by the <code>readLong</code> method |
| 212 | * of interface <code>DataInput</code> , which |
| 213 | * will then return a <code>long</code> equal |
| 214 | * to <code>v</code>. |
| 215 | * |
| 216 | * @param v the <code>long</code> value to be written. |
| 217 | * @throws IOException if an I/O error occurs. |
| 218 | */ |
| 219 | void writeLong(long v) throws IOException; |
| 220 | |
| 221 | /** |
| 222 | * Writes a <code>float</code> value, |
| 223 | * which is comprised of four bytes, to the output stream. |
| 224 | * It does this as if it first converts this |
| 225 | * <code>float</code> value to an <code>int</code> |
| 226 | * in exactly the manner of the <code>Float.floatToIntBits</code> |
| 227 | * method and then writes the <code>int</code> |
| 228 | * value in exactly the manner of the <code>writeInt</code> |
| 229 | * method. The bytes written by this method |
| 230 | * may be read by the <code>readFloat</code> |
| 231 | * method of interface <code>DataInput</code>, |
| 232 | * which will then return a <code>float</code> |
| 233 | * equal to <code>v</code>. |
| 234 | * |
| 235 | * @param v the <code>float</code> value to be written. |
| 236 | * @throws IOException if an I/O error occurs. |
| 237 | */ |
| 238 | void writeFloat(float v) throws IOException; |
| 239 | |
| 240 | /** |
| 241 | * Writes a <code>double</code> value, |
| 242 | * which is comprised of eight bytes, to the output stream. |
| 243 | * It does this as if it first converts this |
| 244 | * <code>double</code> value to a <code>long</code> |
| 245 | * in exactly the manner of the <code>Double.doubleToLongBits</code> |
| 246 | * method and then writes the <code>long</code> |
| 247 | * value in exactly the manner of the <code>writeLong</code> |
| 248 | * method. The bytes written by this method |
| 249 | * may be read by the <code>readDouble</code> |
| 250 | * method of interface <code>DataInput</code>, |
| 251 | * which will then return a <code>double</code> |
| 252 | * equal to <code>v</code>. |
| 253 | * |
| 254 | * @param v the <code>double</code> value to be written. |
| 255 | * @throws IOException if an I/O error occurs. |
| 256 | */ |
| 257 | void writeDouble(double v) throws IOException; |
| 258 | |
| 259 | /** |
| 260 | * Writes a string to the output stream. |
| 261 | * For every character in the string |
| 262 | * <code>s</code>, taken in order, one byte |
| 263 | * is written to the output stream. If |
| 264 | * <code>s</code> is <code>null</code>, a <code>NullPointerException</code> |
| 265 | * is thrown.<p> If <code>s.length</code> |
| 266 | * is zero, then no bytes are written. Otherwise, |
| 267 | * the character <code>s[0]</code> is written |
| 268 | * first, then <code>s[1]</code>, and so on; |
| 269 | * the last character written is <code>s[s.length-1]</code>. |
| 270 | * For each character, one byte is written, |
| 271 | * the low-order byte, in exactly the manner |
| 272 | * of the <code>writeByte</code> method . The |
| 273 | * high-order eight bits of each character |
| 274 | * in the string are ignored. |
| 275 | * |
| 276 | * @param s the string of bytes to be written. |
| 277 | * @throws IOException if an I/O error occurs. |
| 278 | */ |
| 279 | void writeBytes(String s) throws IOException; |
| 280 | |
| 281 | /** |
| 282 | * Writes every character in the string <code>s</code>, |
| 283 | * to the output stream, in order, |
| 284 | * two bytes per character. If <code>s</code> |
| 285 | * is <code>null</code>, a <code>NullPointerException</code> |
| 286 | * is thrown. If <code>s.length</code> |
| 287 | * is zero, then no characters are written. |
| 288 | * Otherwise, the character <code>s[0]</code> |
| 289 | * is written first, then <code>s[1]</code>, |
| 290 | * and so on; the last character written is |
| 291 | * <code>s[s.length-1]</code>. For each character, |
| 292 | * two bytes are actually written, high-order |
| 293 | * byte first, in exactly the manner of the |
| 294 | * <code>writeChar</code> method. |
| 295 | * |
| 296 | * @param s the string value to be written. |
| 297 | * @throws IOException if an I/O error occurs. |
| 298 | */ |
| 299 | void writeChars(String s) throws IOException; |
| 300 | |
| 301 | /** |
| 302 | * Writes two bytes of length information |
| 303 | * to the output stream, followed |
| 304 | * by the |
| 305 | * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> |
| 306 | * representation |
| 307 | * of every character in the string <code>s</code>. |
| 308 | * If <code>s</code> is <code>null</code>, |
| 309 | * a <code>NullPointerException</code> is thrown. |
| 310 | * Each character in the string <code>s</code> |
| 311 | * is converted to a group of one, two, or |
| 312 | * three bytes, depending on the value of the |
| 313 | * character.<p> |
| 314 | * If a character <code>c</code> |
| 315 | * is in the range <code>\u0001</code> through |
| 316 | * <code>\u007f</code>, it is represented |
| 317 | * by one byte:<p> |
| 318 | * <pre>(byte)c </pre> <p> |
| 319 | * If a character <code>c</code> is <code>\u0000</code> |
| 320 | * or is in the range <code>\u0080</code> |
| 321 | * through <code>\u07ff</code>, then it is |
| 322 | * represented by two bytes, to be written |
| 323 | * in the order shown:<p> <pre><code> |
| 324 | * (byte)(0xc0 | (0x1f & (c >> 6))) |
| 325 | * (byte)(0x80 | (0x3f & c)) |
| 326 | * </code></pre> <p> If a character |
| 327 | * <code>c</code> is in the range <code>\u0800</code> |
| 328 | * through <code>uffff</code>, then it is |
| 329 | * represented by three bytes, to be written |
| 330 | * in the order shown:<p> <pre><code> |
| 331 | * (byte)(0xe0 | (0x0f & (c >> 12))) |
| 332 | * (byte)(0x80 | (0x3f & (c >> 6))) |
| 333 | * (byte)(0x80 | (0x3f & c)) |
| 334 | * </code></pre> <p> First, |
| 335 | * the total number of bytes needed to represent |
| 336 | * all the characters of <code>s</code> is |
| 337 | * calculated. If this number is larger than |
| 338 | * <code>65535</code>, then a <code>UTFDataFormatException</code> |
| 339 | * is thrown. Otherwise, this length is written |
| 340 | * to the output stream in exactly the manner |
| 341 | * of the <code>writeShort</code> method; |
| 342 | * after this, the one-, two-, or three-byte |
| 343 | * representation of each character in the |
| 344 | * string <code>s</code> is written.<p> The |
| 345 | * bytes written by this method may be read |
| 346 | * by the <code>readUTF</code> method of interface |
| 347 | * <code>DataInput</code> , which will then |
| 348 | * return a <code>String</code> equal to <code>s</code>. |
| 349 | * |
| 350 | * @param s the string value to be written. |
| 351 | * @throws IOException if an I/O error occurs. |
| 352 | */ |
| 353 | void writeUTF(String s) throws IOException; |
| 354 | } |