| /* Collator.java -- Perform locale dependent String comparisons. |
| Copyright (C) 1998, 1999, 2000, 2001, 2004, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.text; |
| |
| import gnu.java.locale.LocaleHelper; |
| |
| import java.util.Comparator; |
| import java.util.Locale; |
| import java.util.MissingResourceException; |
| import java.util.ResourceBundle; |
| |
| /** |
| * This class is the abstract superclass of classes which perform |
| * locale dependent <code>String</code> comparisons. A caller requests |
| * an instance of <code>Collator</code> for a particular locale using |
| * the <code>getInstance()</code> static method in this class. That method |
| * will return a locale specific subclass of <code>Collator</code> which |
| * can be used to perform <code>String</code> comparisons for that locale. |
| * If a subclass of <code>Collator</code> cannot be located for a particular |
| * locale, a default instance for the current locale will be returned. |
| * |
| * In addition to setting the correct locale, there are two additional |
| * settings that can be adjusted to affect <code>String</code> comparisons: |
| * strength and decomposition. The strength value determines the level |
| * of signficance of character differences required for them to sort |
| * differently. (For example, whether or not capital letters are considered |
| * different from lower case letters). The decomposition value affects how |
| * variants of the same character are treated for sorting purposes. (For |
| * example, whether or not an accent is signficant or not). These settings |
| * are described in detail in the documentation for the methods and values |
| * that are related to them. |
| * |
| * @author Tom Tromey (tromey@cygnus.com) |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @date March 18, 1999 |
| */ |
| public abstract class Collator implements Comparator, Cloneable |
| { |
| /** |
| * This constant is a strength value which indicates that only primary |
| * differences between characters will be considered signficant. As an |
| * example, two completely different English letters such as 'a' and 'b' |
| * are considered to have a primary difference. |
| */ |
| public static final int PRIMARY = 0; |
| |
| /** |
| * This constant is a strength value which indicates that only secondary |
| * or primary differences between characters will be considered |
| * significant. An example of a secondary difference between characters |
| * are instances of the same letter with different accented forms. |
| */ |
| public static final int SECONDARY = 1; |
| |
| /** |
| * This constant is a strength value which indicates that tertiary, |
| * secondary, and primary differences will be considered during sorting. |
| * An example of a tertiary difference is capitalization of a given letter. |
| * This is the default value for the strength setting. |
| */ |
| public static final int TERTIARY = 2; |
| |
| /** |
| * This constant is a strength value which indicates that any difference |
| * at all between character values are considered significant. |
| */ |
| public static final int IDENTICAL = 3; |
| |
| /** |
| * This constant indicates that accented characters won't be decomposed |
| * when performing comparisons. This will yield the fastest results, but |
| * will only work correctly in call cases for languages which do not |
| * use accents such as English. |
| */ |
| public static final int NO_DECOMPOSITION = 0; |
| |
| /** |
| * This constant indicates that only characters which are canonical variants |
| * in Unicode 2.0 will be decomposed prior to performing comparisons. This |
| * will cause accented languages to be sorted correctly. This is the |
| * default decomposition value. |
| */ |
| public static final int CANONICAL_DECOMPOSITION = 1; |
| |
| /** |
| * This constant indicates that both canonical variants and compatibility |
| * variants in Unicode 2.0 will be decomposed prior to performing |
| * comparisons. This is the slowest mode, but is required to get the |
| * correct sorting for certain languages with certain special formats. |
| */ |
| public static final int FULL_DECOMPOSITION = 2; |
| |
| /** |
| * This method initializes a new instance of <code>Collator</code> to have |
| * the default strength (TERTIARY) and decomposition |
| * (CANONICAL_DECOMPOSITION) settings. This constructor is protected and |
| * is for use by subclasses only. Non-subclass callers should use the |
| * static <code>getInstance()</code> methods of this class to instantiate |
| * <code>Collation</code> objects for the desired locale. |
| */ |
| protected Collator () |
| { |
| strength = TERTIARY; |
| decmp = CANONICAL_DECOMPOSITION; |
| } |
| |
| /** |
| * This method compares the two <code>String</code>'s and returns an |
| * integer indicating whether or not the first argument is less than, |
| * equal to, or greater than the second argument. The comparison is |
| * performed according to the rules of the locale for this |
| * <code>Collator</code> and the strength and decomposition rules in |
| * effect. |
| * |
| * @param source The first object to compare |
| * @param target The second object to compare |
| * |
| * @return A negative integer if str1 < str2, 0 if str1 == str2, or |
| * a positive integer if str1 > str2. |
| */ |
| public abstract int compare (String source, String target); |
| |
| /** |
| * This method compares the two <code>Object</code>'s and returns an |
| * integer indicating whether or not the first argument is less than, |
| * equal to, or greater than the second argument. These two objects |
| * must be <code>String</code>'s or an exception will be thrown. |
| * |
| * @param o1 The first object to compare |
| * @param o2 The second object to compare |
| * |
| * @return A negative integer if obj1 < obj2, 0 if obj1 == obj2, or |
| * a positive integer if obj1 > obj2. |
| * |
| * @exception ClassCastException If the arguments are not instances |
| * of <code>String</code>. |
| */ |
| public int compare (Object o1, Object o2) |
| { |
| return compare ((String) o1, (String) o2); |
| } |
| |
| /** |
| * This method tests the specified object for equality against this |
| * object. This will be true if and only if the following conditions are |
| * met: |
| * <ul> |
| * <li>The specified object is not <code>null</code>.</li> |
| * <li>The specified object is an instance of <code>Collator</code>.</li> |
| * <li>The specified object has the same strength and decomposition |
| * settings as this object.</li> |
| * </ul> |
| * |
| * @param obj The <code>Object</code> to test for equality against |
| * this object. |
| * |
| * @return <code>true</code> if the specified object is equal to |
| * this one, <code>false</code> otherwise. |
| */ |
| public boolean equals (Object obj) |
| { |
| if (! (obj instanceof Collator)) |
| return false; |
| Collator c = (Collator) obj; |
| return decmp == c.decmp && strength == c.strength; |
| } |
| |
| /** |
| * This method tests whether the specified <code>String</code>'s are equal |
| * according to the collation rules for the locale of this object and |
| * the current strength and decomposition settings. |
| * |
| * @param source The first <code>String</code> to compare |
| * @param target The second <code>String</code> to compare |
| * |
| * @return <code>true</code> if the two strings are equal, |
| * <code>false</code> otherwise. |
| */ |
| public boolean equals (String source, String target) |
| { |
| return compare (source, target) == 0; |
| } |
| |
| /** |
| * This method returns a copy of this <code>Collator</code> object. |
| * |
| * @return A duplicate of this object. |
| */ |
| public Object clone () |
| { |
| try |
| { |
| return super.clone (); |
| } |
| catch (CloneNotSupportedException _) |
| { |
| return null; |
| } |
| } |
| |
| /** |
| * This method returns an array of <code>Locale</code> objects which is |
| * the list of locales for which <code>Collator</code> objects exist. |
| * |
| * @return The list of locales for which <code>Collator</code>'s exist. |
| */ |
| public static synchronized Locale[] getAvailableLocales () |
| { |
| return LocaleHelper.getCollatorLocales(); |
| } |
| |
| /** |
| * This method transforms the specified <code>String</code> into a |
| * <code>CollationKey</code> for faster comparisons. This is useful when |
| * comparisons against a string might be performed multiple times, such |
| * as during a sort operation. |
| * |
| * @param source The <code>String</code> to convert. |
| * |
| * @return A <code>CollationKey</code> for the specified <code>String</code>. |
| */ |
| public abstract CollationKey getCollationKey (String source); |
| |
| /** |
| * This method returns the current decomposition setting for this |
| * object. This * will be one of NO_DECOMPOSITION, |
| * CANONICAL_DECOMPOSITION, or * FULL_DECOMPOSITION. See the |
| * documentation for those constants for an * explanation of this |
| * setting. |
| * |
| * @return The current decomposition setting. |
| */ |
| public synchronized int getDecomposition () |
| { |
| return decmp; |
| } |
| |
| /** |
| * This method returns an instance of <code>Collator</code> for the |
| * default locale. |
| * |
| * @return A <code>Collator</code> for the default locale. |
| */ |
| public static Collator getInstance () |
| { |
| return getInstance (Locale.getDefault()); |
| } |
| |
| /** |
| * This method returns an instance of <code>Collator</code> for the |
| * specified locale. If no <code>Collator</code> exists for the desired |
| * locale, a <code>Collator</code> for the default locale will be returned. |
| * |
| * @param loc The desired locale to load a <code>Collator</code> for. |
| * |
| * @return A <code>Collator</code> for the requested locale |
| */ |
| public static Collator getInstance (Locale loc) |
| { |
| ResourceBundle res; |
| String pattern; |
| try |
| { |
| res = ResourceBundle.getBundle("gnu.java.locale.LocaleInformation", |
| loc, ClassLoader.getSystemClassLoader()); |
| pattern = res.getString("collation_rules"); |
| } |
| catch (MissingResourceException x) |
| { |
| pattern = "<0<1<2<3<4<5<6<7<8<9<A,a<b,B<c,C<d,D<e,E<f,F<g,G<h,H<i,I<j,J<k,K" + |
| "<l,L<m,M<n,N<o,O<p,P<q,Q<r,R<s,S<t,T<u,U<v,V<w,W<x,X<y,Y<z,Z"; |
| } |
| try |
| { |
| return new RuleBasedCollator (pattern); |
| } |
| catch (ParseException x) |
| { |
| throw (InternalError)new InternalError().initCause(x); |
| } |
| } |
| |
| /** |
| * This method returns the current strength setting for this object. This |
| * will be one of PRIMARY, SECONDARY, TERTIARY, or IDENTICAL. See the |
| * documentation for those constants for an explanation of this setting. |
| * |
| * @return The current strength setting. |
| */ |
| public synchronized int getStrength () |
| { |
| return strength; |
| } |
| |
| /** |
| * This method returns a hash code value for this object. |
| * |
| * @return A hash value for this object. |
| */ |
| public abstract int hashCode (); |
| |
| /** |
| * This method sets the decomposition setting for this object to the |
| * specified value. This must be one of NO_DECOMPOSITION, |
| * CANONICAL_DECOMPOSITION, or FULL_DECOMPOSITION. Otherwise an |
| * exception will be thrown. See the documentation for those |
| * contants for an explanation of this setting. |
| * |
| * @param mode The new decomposition setting. |
| * |
| * @exception IllegalArgumentException If the requested |
| * decomposition setting is not valid. |
| */ |
| public synchronized void setDecomposition (int mode) |
| { |
| if (mode != NO_DECOMPOSITION |
| && mode != CANONICAL_DECOMPOSITION |
| && mode != FULL_DECOMPOSITION) |
| throw new IllegalArgumentException (); |
| decmp = mode; |
| } |
| |
| /** |
| * This method sets the strength setting for this object to the specified |
| * value. This must be one of PRIMARY, SECONDARY, TERTIARY, or IDENTICAL. |
| * Otherwise an exception is thrown. See the documentation for these |
| * constants for an explanation of this setting. |
| * |
| * @param strength The new strength setting. |
| * |
| * @exception IllegalArgumentException If the requested strength |
| * setting value is not valid. |
| */ |
| public synchronized void setStrength (int strength) |
| { |
| if (strength != PRIMARY && strength != SECONDARY |
| && strength != TERTIARY && strength != IDENTICAL) |
| throw new IllegalArgumentException (); |
| this.strength = strength; |
| } |
| |
| // Decompose a single character and append results to the buffer. |
| // FIXME: for libgcj this is a native method which handles |
| // decomposition. For Classpath, for now, it does nothing. |
| final void decomposeCharacter (char c, StringBuffer buf) |
| { |
| buf.append (c); |
| } |
| |
| /** |
| * This is the current collation decomposition setting. |
| */ |
| int decmp; |
| |
| /** |
| * This is the current collation strength setting. |
| */ |
| int strength; |
| } |