J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2005 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 | /* |
| 27 | * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved |
| 28 | * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved |
| 29 | * |
| 30 | * The original version of this source code and documentation is copyrighted |
| 31 | * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These |
| 32 | * materials are provided under terms of a License Agreement between Taligent |
| 33 | * and Sun. This technology is protected by multiple US and International |
| 34 | * patents. This notice and attribution to Taligent may not be removed. |
| 35 | * Taligent is a registered trademark of Taligent, Inc. |
| 36 | * |
| 37 | */ |
| 38 | |
| 39 | package java.text; |
| 40 | |
| 41 | import java.io.Serializable; |
| 42 | |
| 43 | /** |
| 44 | * <code>Format</code> is an abstract base class for formatting locale-sensitive |
| 45 | * information such as dates, messages, and numbers. |
| 46 | * |
| 47 | * <p> |
| 48 | * <code>Format</code> defines the programming interface for formatting |
| 49 | * locale-sensitive objects into <code>String</code>s (the |
| 50 | * <code>format</code> method) and for parsing <code>String</code>s back |
| 51 | * into objects (the <code>parseObject</code> method). |
| 52 | * |
| 53 | * <p> |
| 54 | * Generally, a format's <code>parseObject</code> method must be able to parse |
| 55 | * any string formatted by its <code>format</code> method. However, there may |
| 56 | * be exceptional cases where this is not possible. For example, a |
| 57 | * <code>format</code> method might create two adjacent integer numbers with |
| 58 | * no separator in between, and in this case the <code>parseObject</code> could |
| 59 | * not tell which digits belong to which number. |
| 60 | * |
| 61 | * <h4>Subclassing</h4> |
| 62 | * |
| 63 | * <p> |
| 64 | * The Java Platform provides three specialized subclasses of <code>Format</code>-- |
| 65 | * <code>DateFormat</code>, <code>MessageFormat</code>, and |
| 66 | * <code>NumberFormat</code>--for formatting dates, messages, and numbers, |
| 67 | * respectively. |
| 68 | * <p> |
| 69 | * Concrete subclasses must implement three methods: |
| 70 | * <ol> |
| 71 | * <li> <code>format(Object obj, StringBuffer toAppendTo, FieldPosition pos)</code> |
| 72 | * <li> <code>formatToCharacterIterator(Object obj)</code> |
| 73 | * <li> <code>parseObject(String source, ParsePosition pos)</code> |
| 74 | * </ol> |
| 75 | * These general methods allow polymorphic parsing and formatting of objects |
| 76 | * and are used, for example, by <code>MessageFormat</code>. |
| 77 | * Subclasses often also provide additional <code>format</code> methods for |
| 78 | * specific input types as well as <code>parse</code> methods for specific |
| 79 | * result types. Any <code>parse</code> method that does not take a |
| 80 | * <code>ParsePosition</code> argument should throw <code>ParseException</code> |
| 81 | * when no text in the required format is at the beginning of the input text. |
| 82 | * |
| 83 | * <p> |
| 84 | * Most subclasses will also implement the following factory methods: |
| 85 | * <ol> |
| 86 | * <li> |
| 87 | * <code>getInstance</code> for getting a useful format object appropriate |
| 88 | * for the current locale |
| 89 | * <li> |
| 90 | * <code>getInstance(Locale)</code> for getting a useful format |
| 91 | * object appropriate for the specified locale |
| 92 | * </ol> |
| 93 | * In addition, some subclasses may also implement other |
| 94 | * <code>getXxxxInstance</code> methods for more specialized control. For |
| 95 | * example, the <code>NumberFormat</code> class provides |
| 96 | * <code>getPercentInstance</code> and <code>getCurrencyInstance</code> |
| 97 | * methods for getting specialized number formatters. |
| 98 | * |
| 99 | * <p> |
| 100 | * Subclasses of <code>Format</code> that allow programmers to create objects |
| 101 | * for locales (with <code>getInstance(Locale)</code> for example) |
| 102 | * must also implement the following class method: |
| 103 | * <blockquote> |
| 104 | * <pre> |
| 105 | * public static Locale[] getAvailableLocales() |
| 106 | * </pre> |
| 107 | * </blockquote> |
| 108 | * |
| 109 | * <p> |
| 110 | * And finally subclasses may define a set of constants to identify the various |
| 111 | * fields in the formatted output. These constants are used to create a FieldPosition |
| 112 | * object which identifies what information is contained in the field and its |
| 113 | * position in the formatted result. These constants should be named |
| 114 | * <code><em>item</em>_FIELD</code> where <code><em>item</em></code> identifies |
| 115 | * the field. For examples of these constants, see <code>ERA_FIELD</code> and its |
| 116 | * friends in {@link DateFormat}. |
| 117 | * |
| 118 | * <h4><a name="synchronization">Synchronization</a></h4> |
| 119 | * |
| 120 | * <p> |
| 121 | * Formats are generally not synchronized. |
| 122 | * It is recommended to create separate format instances for each thread. |
| 123 | * If multiple threads access a format concurrently, it must be synchronized |
| 124 | * externally. |
| 125 | * |
| 126 | * @see java.text.ParsePosition |
| 127 | * @see java.text.FieldPosition |
| 128 | * @see java.text.NumberFormat |
| 129 | * @see java.text.DateFormat |
| 130 | * @see java.text.MessageFormat |
| 131 | * @author Mark Davis |
| 132 | */ |
| 133 | public abstract class Format implements Serializable, Cloneable { |
| 134 | |
| 135 | private static final long serialVersionUID = -299282585814624189L; |
| 136 | |
| 137 | /** |
| 138 | * Sole constructor. (For invocation by subclass constructors, typically |
| 139 | * implicit.) |
| 140 | */ |
| 141 | protected Format() { |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Formats an object to produce a string. This is equivalent to |
| 146 | * <blockquote> |
| 147 | * {@link #format(Object, StringBuffer, FieldPosition) format}<code>(obj, |
| 148 | * new StringBuffer(), new FieldPosition(0)).toString();</code> |
| 149 | * </blockquote> |
| 150 | * |
| 151 | * @param obj The object to format |
| 152 | * @return Formatted string. |
| 153 | * @exception IllegalArgumentException if the Format cannot format the given |
| 154 | * object |
| 155 | */ |
| 156 | public final String format (Object obj) { |
| 157 | return format(obj, new StringBuffer(), new FieldPosition(0)).toString(); |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Formats an object and appends the resulting text to a given string |
| 162 | * buffer. |
| 163 | * If the <code>pos</code> argument identifies a field used by the format, |
| 164 | * then its indices are set to the beginning and end of the first such |
| 165 | * field encountered. |
| 166 | * |
| 167 | * @param obj The object to format |
| 168 | * @param toAppendTo where the text is to be appended |
| 169 | * @param pos A <code>FieldPosition</code> identifying a field |
| 170 | * in the formatted text |
| 171 | * @return the string buffer passed in as <code>toAppendTo</code>, |
| 172 | * with formatted text appended |
| 173 | * @exception NullPointerException if <code>toAppendTo</code> or |
| 174 | * <code>pos</code> is null |
| 175 | * @exception IllegalArgumentException if the Format cannot format the given |
| 176 | * object |
| 177 | */ |
| 178 | public abstract StringBuffer format(Object obj, |
| 179 | StringBuffer toAppendTo, |
| 180 | FieldPosition pos); |
| 181 | |
| 182 | /** |
| 183 | * Formats an Object producing an <code>AttributedCharacterIterator</code>. |
| 184 | * You can use the returned <code>AttributedCharacterIterator</code> |
| 185 | * to build the resulting String, as well as to determine information |
| 186 | * about the resulting String. |
| 187 | * <p> |
| 188 | * Each attribute key of the AttributedCharacterIterator will be of type |
| 189 | * <code>Field</code>. It is up to each <code>Format</code> implementation |
| 190 | * to define what the legal values are for each attribute in the |
| 191 | * <code>AttributedCharacterIterator</code>, but typically the attribute |
| 192 | * key is also used as the attribute value. |
| 193 | * <p>The default implementation creates an |
| 194 | * <code>AttributedCharacterIterator</code> with no attributes. Subclasses |
| 195 | * that support fields should override this and create an |
| 196 | * <code>AttributedCharacterIterator</code> with meaningful attributes. |
| 197 | * |
| 198 | * @exception NullPointerException if obj is null. |
| 199 | * @exception IllegalArgumentException when the Format cannot format the |
| 200 | * given object. |
| 201 | * @param obj The object to format |
| 202 | * @return AttributedCharacterIterator describing the formatted value. |
| 203 | * @since 1.4 |
| 204 | */ |
| 205 | public AttributedCharacterIterator formatToCharacterIterator(Object obj) { |
| 206 | return createAttributedCharacterIterator(format(obj)); |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Parses text from a string to produce an object. |
| 211 | * <p> |
| 212 | * The method attempts to parse text starting at the index given by |
| 213 | * <code>pos</code>. |
| 214 | * If parsing succeeds, then the index of <code>pos</code> is updated |
| 215 | * to the index after the last character used (parsing does not necessarily |
| 216 | * use all characters up to the end of the string), and the parsed |
| 217 | * object is returned. The updated <code>pos</code> can be used to |
| 218 | * indicate the starting point for the next call to this method. |
| 219 | * If an error occurs, then the index of <code>pos</code> is not |
| 220 | * changed, the error index of <code>pos</code> is set to the index of |
| 221 | * the character where the error occurred, and null is returned. |
| 222 | * |
| 223 | * @param source A <code>String</code>, part of which should be parsed. |
| 224 | * @param pos A <code>ParsePosition</code> object with index and error |
| 225 | * index information as described above. |
| 226 | * @return An <code>Object</code> parsed from the string. In case of |
| 227 | * error, returns null. |
| 228 | * @exception NullPointerException if <code>pos</code> is null. |
| 229 | */ |
| 230 | public abstract Object parseObject (String source, ParsePosition pos); |
| 231 | |
| 232 | /** |
| 233 | * Parses text from the beginning of the given string to produce an object. |
| 234 | * The method may not use the entire text of the given string. |
| 235 | * |
| 236 | * @param source A <code>String</code> whose beginning should be parsed. |
| 237 | * @return An <code>Object</code> parsed from the string. |
| 238 | * @exception ParseException if the beginning of the specified string |
| 239 | * cannot be parsed. |
| 240 | */ |
| 241 | public Object parseObject(String source) throws ParseException { |
| 242 | ParsePosition pos = new ParsePosition(0); |
| 243 | Object result = parseObject(source, pos); |
| 244 | if (pos.index == 0) { |
| 245 | throw new ParseException("Format.parseObject(String) failed", |
| 246 | pos.errorIndex); |
| 247 | } |
| 248 | return result; |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Creates and returns a copy of this object. |
| 253 | * |
| 254 | * @return a clone of this instance. |
| 255 | */ |
| 256 | public Object clone() { |
| 257 | try { |
| 258 | return super.clone(); |
| 259 | } catch (CloneNotSupportedException e) { |
| 260 | // will never happen |
| 261 | return null; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | // |
| 266 | // Convenience methods for creating AttributedCharacterIterators from |
| 267 | // different parameters. |
| 268 | // |
| 269 | |
| 270 | /** |
| 271 | * Creates an <code>AttributedCharacterIterator</code> for the String |
| 272 | * <code>s</code>. |
| 273 | * |
| 274 | * @param s String to create AttributedCharacterIterator from |
| 275 | * @return AttributedCharacterIterator wrapping s |
| 276 | */ |
| 277 | AttributedCharacterIterator createAttributedCharacterIterator(String s) { |
| 278 | AttributedString as = new AttributedString(s); |
| 279 | |
| 280 | return as.getIterator(); |
| 281 | } |
| 282 | |
| 283 | /** |
| 284 | * Creates an <code>AttributedCharacterIterator</code> containg the |
| 285 | * concatenated contents of the passed in |
| 286 | * <code>AttributedCharacterIterator</code>s. |
| 287 | * |
| 288 | * @param iterators AttributedCharacterIterators used to create resulting |
| 289 | * AttributedCharacterIterators |
| 290 | * @return AttributedCharacterIterator wrapping passed in |
| 291 | * AttributedCharacterIterators |
| 292 | */ |
| 293 | AttributedCharacterIterator createAttributedCharacterIterator( |
| 294 | AttributedCharacterIterator[] iterators) { |
| 295 | AttributedString as = new AttributedString(iterators); |
| 296 | |
| 297 | return as.getIterator(); |
| 298 | } |
| 299 | |
| 300 | /** |
| 301 | * Returns an AttributedCharacterIterator with the String |
| 302 | * <code>string</code> and additional key/value pair <code>key</code>, |
| 303 | * <code>value</code>. |
| 304 | * |
| 305 | * @param string String to create AttributedCharacterIterator from |
| 306 | * @param key Key for AttributedCharacterIterator |
| 307 | * @param value Value associated with key in AttributedCharacterIterator |
| 308 | * @return AttributedCharacterIterator wrapping args |
| 309 | */ |
| 310 | AttributedCharacterIterator createAttributedCharacterIterator( |
| 311 | String string, AttributedCharacterIterator.Attribute key, |
| 312 | Object value) { |
| 313 | AttributedString as = new AttributedString(string); |
| 314 | |
| 315 | as.addAttribute(key, value); |
| 316 | return as.getIterator(); |
| 317 | } |
| 318 | |
| 319 | /** |
| 320 | * Creates an AttributedCharacterIterator with the contents of |
| 321 | * <code>iterator</code> and the additional attribute <code>key</code> |
| 322 | * <code>value</code>. |
| 323 | * |
| 324 | * @param iterator Initial AttributedCharacterIterator to add arg to |
| 325 | * @param key Key for AttributedCharacterIterator |
| 326 | * @param value Value associated with key in AttributedCharacterIterator |
| 327 | * @return AttributedCharacterIterator wrapping args |
| 328 | */ |
| 329 | AttributedCharacterIterator createAttributedCharacterIterator( |
| 330 | AttributedCharacterIterator iterator, |
| 331 | AttributedCharacterIterator.Attribute key, Object value) { |
| 332 | AttributedString as = new AttributedString(iterator); |
| 333 | |
| 334 | as.addAttribute(key, value); |
| 335 | return as.getIterator(); |
| 336 | } |
| 337 | |
| 338 | |
| 339 | /** |
| 340 | * Defines constants that are used as attribute keys in the |
| 341 | * <code>AttributedCharacterIterator</code> returned |
| 342 | * from <code>Format.formatToCharacterIterator</code> and as |
| 343 | * field identifiers in <code>FieldPosition</code>. |
| 344 | * |
| 345 | * @since 1.4 |
| 346 | */ |
| 347 | public static class Field extends AttributedCharacterIterator.Attribute { |
| 348 | |
| 349 | // Proclaim serial compatibility with 1.4 FCS |
| 350 | private static final long serialVersionUID = 276966692217360283L; |
| 351 | |
| 352 | /** |
| 353 | * Creates a Field with the specified name. |
| 354 | * |
| 355 | * @param name Name of the attribute |
| 356 | */ |
| 357 | protected Field(String name) { |
| 358 | super(name); |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | |
| 363 | /** |
| 364 | * FieldDelegate is notified by the various <code>Format</code> |
| 365 | * implementations as they are formatting the Objects. This allows for |
| 366 | * storage of the individual sections of the formatted String for |
| 367 | * later use, such as in a <code>FieldPosition</code> or for an |
| 368 | * <code>AttributedCharacterIterator</code>. |
| 369 | * <p> |
| 370 | * Delegates should NOT assume that the <code>Format</code> will notify |
| 371 | * the delegate of fields in any particular order. |
| 372 | * |
| 373 | * @see FieldPosition.Delegate |
| 374 | * @see CharacterIteratorFieldDelegate |
| 375 | */ |
| 376 | interface FieldDelegate { |
| 377 | /** |
| 378 | * Notified when a particular region of the String is formatted. This |
| 379 | * method will be invoked if there is no corresponding integer field id |
| 380 | * matching <code>attr</code>. |
| 381 | * |
| 382 | * @param attr Identifies the field matched |
| 383 | * @param value Value associated with the field |
| 384 | * @param start Beginning location of the field, will be >= 0 |
| 385 | * @param end End of the field, will be >= start and <= buffer.length() |
| 386 | * @param buffer Contains current formatted value, receiver should |
| 387 | * NOT modify it. |
| 388 | */ |
| 389 | public void formatted(Format.Field attr, Object value, int start, |
| 390 | int end, StringBuffer buffer); |
| 391 | |
| 392 | /** |
| 393 | * Notified when a particular region of the String is formatted. |
| 394 | * |
| 395 | * @param fieldID Identifies the field by integer |
| 396 | * @param attr Identifies the field matched |
| 397 | * @param value Value associated with the field |
| 398 | * @param start Beginning location of the field, will be >= 0 |
| 399 | * @param end End of the field, will be >= start and <= buffer.length() |
| 400 | * @param buffer Contains current formatted value, receiver should |
| 401 | * NOT modify it. |
| 402 | */ |
| 403 | public void formatted(int fieldID, Format.Field attr, Object value, |
| 404 | int start, int end, StringBuffer buffer); |
| 405 | } |
| 406 | } |