1 /* 2 * Copyright (c) 1996, 2013, 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 /* 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 * <h3>Subclassing</h3> 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 */ Format()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 */ format(Object obj)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 */ format(Object obj, StringBuffer toAppendTo, FieldPosition pos)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 */ formatToCharacterIterator(Object obj)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 */ parseObject(String source, ParsePosition pos)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 */ parseObject(String source)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 */ clone()256 public Object clone() { 257 try { 258 return super.clone(); 259 } catch (CloneNotSupportedException e) { 260 // will never happen 261 throw new InternalError(e); 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 */ createAttributedCharacterIterator(String s)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> containing 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 */ createAttributedCharacterIterator( AttributedCharacterIterator[] iterators)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 */ createAttributedCharacterIterator( String string, AttributedCharacterIterator.Attribute key, Object value)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 */ createAttributedCharacterIterator( AttributedCharacterIterator iterator, AttributedCharacterIterator.Attribute key, Object value)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 */ Field(String name)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#getFieldDelegate 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 */ formatted(Format.Field attr, Object value, int start, int end, StringBuffer buffer)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 */ formatted(int fieldID, Format.Field attr, Object value, int start, int end, StringBuffer buffer)403 public void formatted(int fieldID, Format.Field attr, Object value, 404 int start, int end, StringBuffer buffer); 405 } 406 } 407