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1: /* Collator.java -- Perform locale dependent String comparisons. 2: Copyright (C) 1998, 1999, 2000, 2001, 2004, 2005, 2007, 3: 2008 Free Software Foundation, Inc. 4: 5: This file is part of GNU Classpath. 6: 7: GNU Classpath is free software; you can redistribute it and/or modify 8: it under the terms of the GNU General Public License as published by 9: the Free Software Foundation; either version 2, or (at your option) 10: any later version. 11: 12: GNU Classpath is distributed in the hope that it will be useful, but 13: WITHOUT ANY WARRANTY; without even the implied warranty of 14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15: General Public License for more details. 16: 17: You should have received a copy of the GNU General Public License 18: along with GNU Classpath; see the file COPYING. If not, write to the 19: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 20: 02110-1301 USA. 21: 22: Linking this library statically or dynamically with other modules is 23: making a combined work based on this library. Thus, the terms and 24: conditions of the GNU General Public License cover the whole 25: combination. 26: 27: As a special exception, the copyright holders of this library give you 28: permission to link this library with independent modules to produce an 29: executable, regardless of the license terms of these independent 30: modules, and to copy and distribute the resulting executable under 31: terms of your choice, provided that you also meet, for each linked 32: independent module, the terms and conditions of the license of that 33: module. An independent module is a module which is not derived from 34: or based on this library. If you modify this library, you may extend 35: this exception to your version of the library, but you are not 36: obligated to do so. If you do not wish to do so, delete this 37: exception statement from your version. */ 38: 39: 40: package java.text; 41: 42: import gnu.java.locale.LocaleHelper; 43: 44: import java.text.spi.CollatorProvider; 45: 46: import java.util.Comparator; 47: import java.util.Locale; 48: import java.util.MissingResourceException; 49: import java.util.ResourceBundle; 50: import java.util.ServiceLoader; 51: 52: /** 53: * This class is the abstract superclass of classes which perform 54: * locale dependent <code>String</code> comparisons. A caller requests 55: * an instance of <code>Collator</code> for a particular locale using 56: * the <code>getInstance()</code> static method in this class. That method 57: * will return a locale specific subclass of <code>Collator</code> which 58: * can be used to perform <code>String</code> comparisons for that locale. 59: * If a subclass of <code>Collator</code> cannot be located for a particular 60: * locale, a default instance for the current locale will be returned. 61: * 62: * In addition to setting the correct locale, there are two additional 63: * settings that can be adjusted to affect <code>String</code> comparisons: 64: * strength and decomposition. The strength value determines the level 65: * of signficance of character differences required for them to sort 66: * differently. (For example, whether or not capital letters are considered 67: * different from lower case letters). The decomposition value affects how 68: * variants of the same character are treated for sorting purposes. (For 69: * example, whether or not an accent is signficant or not). These settings 70: * are described in detail in the documentation for the methods and values 71: * that are related to them. 72: * 73: * @author Tom Tromey (tromey@cygnus.com) 74: * @author Aaron M. Renn (arenn@urbanophile.com) 75: * @date March 18, 1999 76: */ 77: public abstract class Collator implements Comparator<Object>, Cloneable 78: { 79: /** 80: * This constant is a strength value which indicates that only primary 81: * differences between characters will be considered signficant. As an 82: * example, two completely different English letters such as 'a' and 'b' 83: * are considered to have a primary difference. 84: */ 85: public static final int PRIMARY = 0; 86: 87: /** 88: * This constant is a strength value which indicates that only secondary 89: * or primary differences between characters will be considered 90: * significant. An example of a secondary difference between characters 91: * are instances of the same letter with different accented forms. 92: */ 93: public static final int SECONDARY = 1; 94: 95: /** 96: * This constant is a strength value which indicates that tertiary, 97: * secondary, and primary differences will be considered during sorting. 98: * An example of a tertiary difference is capitalization of a given letter. 99: * This is the default value for the strength setting. 100: */ 101: public static final int TERTIARY = 2; 102: 103: /** 104: * This constant is a strength value which indicates that any difference 105: * at all between character values are considered significant. 106: */ 107: public static final int IDENTICAL = 3; 108: 109: /** 110: * This constant indicates that accented characters won't be decomposed 111: * when performing comparisons. This will yield the fastest results, but 112: * will only work correctly in call cases for languages which do not 113: * use accents such as English. 114: */ 115: public static final int NO_DECOMPOSITION = 0; 116: 117: /** 118: * This constant indicates that only characters which are canonical variants 119: * in Unicode 2.0 will be decomposed prior to performing comparisons. This 120: * will cause accented languages to be sorted correctly. This is the 121: * default decomposition value. 122: */ 123: public static final int CANONICAL_DECOMPOSITION = 1; 124: 125: /** 126: * This constant indicates that both canonical variants and compatibility 127: * variants in Unicode 2.0 will be decomposed prior to performing 128: * comparisons. This is the slowest mode, but is required to get the 129: * correct sorting for certain languages with certain special formats. 130: */ 131: public static final int FULL_DECOMPOSITION = 2; 132: 133: /** 134: * This method initializes a new instance of <code>Collator</code> to have 135: * the default strength (TERTIARY) and decomposition 136: * (CANONICAL_DECOMPOSITION) settings. This constructor is protected and 137: * is for use by subclasses only. Non-subclass callers should use the 138: * static <code>getInstance()</code> methods of this class to instantiate 139: * <code>Collation</code> objects for the desired locale. 140: */ 141: protected Collator () 142: { 143: strength = TERTIARY; 144: decmp = CANONICAL_DECOMPOSITION; 145: } 146: 147: /** 148: * This method compares the two <code>String</code>'s and returns an 149: * integer indicating whether or not the first argument is less than, 150: * equal to, or greater than the second argument. The comparison is 151: * performed according to the rules of the locale for this 152: * <code>Collator</code> and the strength and decomposition rules in 153: * effect. 154: * 155: * @param source The first object to compare 156: * @param target The second object to compare 157: * 158: * @return A negative integer if str1 < str2, 0 if str1 == str2, or 159: * a positive integer if str1 > str2. 160: */ 161: public abstract int compare (String source, String target); 162: 163: /** 164: * This method compares the two <code>Object</code>'s and returns an 165: * integer indicating whether or not the first argument is less than, 166: * equal to, or greater than the second argument. These two objects 167: * must be <code>String</code>'s or an exception will be thrown. 168: * 169: * @param o1 The first object to compare 170: * @param o2 The second object to compare 171: * 172: * @return A negative integer if obj1 < obj2, 0 if obj1 == obj2, or 173: * a positive integer if obj1 > obj2. 174: * 175: * @exception ClassCastException If the arguments are not instances 176: * of <code>String</code>. 177: */ 178: public int compare (Object o1, Object o2) 179: { 180: return compare ((String) o1, (String) o2); 181: } 182: 183: /** 184: * This method tests the specified object for equality against this 185: * object. This will be true if and only if the following conditions are 186: * met: 187: * <ul> 188: * <li>The specified object is not <code>null</code>.</li> 189: * <li>The specified object is an instance of <code>Collator</code>.</li> 190: * <li>The specified object has the same strength and decomposition 191: * settings as this object.</li> 192: * </ul> 193: * 194: * @param obj The <code>Object</code> to test for equality against 195: * this object. 196: * 197: * @return <code>true</code> if the specified object is equal to 198: * this one, <code>false</code> otherwise. 199: */ 200: public boolean equals (Object obj) 201: { 202: if (! (obj instanceof Collator)) 203: return false; 204: Collator c = (Collator) obj; 205: return decmp == c.decmp && strength == c.strength; 206: } 207: 208: /** 209: * This method tests whether the specified <code>String</code>'s are equal 210: * according to the collation rules for the locale of this object and 211: * the current strength and decomposition settings. 212: * 213: * @param source The first <code>String</code> to compare 214: * @param target The second <code>String</code> to compare 215: * 216: * @return <code>true</code> if the two strings are equal, 217: * <code>false</code> otherwise. 218: */ 219: public boolean equals (String source, String target) 220: { 221: return compare (source, target) == 0; 222: } 223: 224: /** 225: * This method returns a copy of this <code>Collator</code> object. 226: * 227: * @return A duplicate of this object. 228: */ 229: public Object clone () 230: { 231: try 232: { 233: return super.clone (); 234: } 235: catch (CloneNotSupportedException _) 236: { 237: return null; 238: } 239: } 240: 241: /** 242: * This method returns an array of <code>Locale</code> objects which is 243: * the list of locales for which <code>Collator</code> objects exist. 244: * 245: * @return The list of locales for which <code>Collator</code>'s exist. 246: */ 247: public static synchronized Locale[] getAvailableLocales () 248: { 249: return LocaleHelper.getCollatorLocales(); 250: } 251: 252: /** 253: * This method transforms the specified <code>String</code> into a 254: * <code>CollationKey</code> for faster comparisons. This is useful when 255: * comparisons against a string might be performed multiple times, such 256: * as during a sort operation. 257: * 258: * @param source The <code>String</code> to convert. 259: * 260: * @return A <code>CollationKey</code> for the specified <code>String</code>. 261: */ 262: public abstract CollationKey getCollationKey (String source); 263: 264: /** 265: * This method returns the current decomposition setting for this 266: * object. This * will be one of NO_DECOMPOSITION, 267: * CANONICAL_DECOMPOSITION, or * FULL_DECOMPOSITION. See the 268: * documentation for those constants for an * explanation of this 269: * setting. 270: * 271: * @return The current decomposition setting. 272: */ 273: public synchronized int getDecomposition () 274: { 275: return decmp; 276: } 277: 278: /** 279: * This method returns an instance of <code>Collator</code> for the 280: * default locale. 281: * 282: * @return A <code>Collator</code> for the default locale. 283: */ 284: public static Collator getInstance () 285: { 286: return getInstance (Locale.getDefault()); 287: } 288: 289: /** 290: * This method returns an instance of <code>Collator</code> for the 291: * specified locale. If no <code>Collator</code> exists for the desired 292: * locale, the fallback procedure described in 293: * {@link java.util.spi.LocaleServiceProvider} is invoked. 294: * 295: * @param loc The desired locale to load a <code>Collator</code> for. 296: * 297: * @return A <code>Collator</code> for the requested locale 298: */ 299: public static Collator getInstance (Locale loc) 300: { 301: String pattern; 302: try 303: { 304: ResourceBundle res = 305: ResourceBundle.getBundle("gnu.java.locale.LocaleInformation", 306: loc, ClassLoader.getSystemClassLoader()); 307: return new RuleBasedCollator(res.getString("collation_rules")); 308: } 309: catch (MissingResourceException x) 310: { 311: /* This means runtime support for the locale 312: * is not available, so we check providers. */ 313: } 314: catch (ParseException x) 315: { 316: throw (InternalError)new InternalError().initCause(x); 317: } 318: for (CollatorProvider p : ServiceLoader.load(CollatorProvider.class)) 319: { 320: for (Locale l : p.getAvailableLocales()) 321: { 322: if (l.equals(loc)) 323: { 324: Collator c = p.getInstance(loc); 325: if (c != null) 326: return c; 327: break; 328: } 329: } 330: } 331: if (loc.equals(Locale.ROOT)) 332: { 333: try 334: { 335: return new RuleBasedCollator("<0<1<2<3<4<5<6<7<8<9<A,a<b,B<c," + 336: "C<d,D<e,E<f,F<g,G<h,H<i,I<j,J<k,K" + 337: "<l,L<m,M<n,N<o,O<p,P<q,Q<r,R<s,S<t,"+ 338: "T<u,U<v,V<w,W<x,X<y,Y<z,Z"); 339: } 340: catch (ParseException x) 341: { 342: throw (InternalError)new InternalError().initCause(x); 343: } 344: } 345: return getInstance(LocaleHelper.getFallbackLocale(loc)); 346: } 347: 348: /** 349: * This method returns the current strength setting for this object. This 350: * will be one of PRIMARY, SECONDARY, TERTIARY, or IDENTICAL. See the 351: * documentation for those constants for an explanation of this setting. 352: * 353: * @return The current strength setting. 354: */ 355: public synchronized int getStrength () 356: { 357: return strength; 358: } 359: 360: /** 361: * This method returns a hash code value for this object. 362: * 363: * @return A hash value for this object. 364: */ 365: public abstract int hashCode (); 366: 367: /** 368: * This method sets the decomposition setting for this object to the 369: * specified value. This must be one of NO_DECOMPOSITION, 370: * CANONICAL_DECOMPOSITION, or FULL_DECOMPOSITION. Otherwise an 371: * exception will be thrown. See the documentation for those 372: * contants for an explanation of this setting. 373: * 374: * @param mode The new decomposition setting. 375: * 376: * @exception IllegalArgumentException If the requested 377: * decomposition setting is not valid. 378: */ 379: public synchronized void setDecomposition (int mode) 380: { 381: if (mode != NO_DECOMPOSITION 382: && mode != CANONICAL_DECOMPOSITION 383: && mode != FULL_DECOMPOSITION) 384: throw new IllegalArgumentException (); 385: decmp = mode; 386: } 387: 388: /** 389: * This method sets the strength setting for this object to the specified 390: * value. This must be one of PRIMARY, SECONDARY, TERTIARY, or IDENTICAL. 391: * Otherwise an exception is thrown. See the documentation for these 392: * constants for an explanation of this setting. 393: * 394: * @param strength The new strength setting. 395: * 396: * @exception IllegalArgumentException If the requested strength 397: * setting value is not valid. 398: */ 399: public synchronized void setStrength (int strength) 400: { 401: if (strength != PRIMARY && strength != SECONDARY 402: && strength != TERTIARY && strength != IDENTICAL) 403: throw new IllegalArgumentException (); 404: this.strength = strength; 405: } 406: 407: // Decompose a single character and append results to the buffer. 408: native final void decomposeCharacter (char c, StringBuffer buf); 409: 410: /** 411: * This is the current collation decomposition setting. 412: */ 413: int decmp; 414: 415: /** 416: * This is the current collation strength setting. 417: */ 418: int strength; 419: }