395 lines
14 KiB
Java
395 lines
14 KiB
Java
/* Collator.java -- Perform locale dependent String comparisons.
|
|
Copyright (C) 1998, 1999, 2000, 2001 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., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 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 java.util.Locale;
|
|
import java.util.MissingResourceException;
|
|
import java.util.ResourceBundle;
|
|
import java.util.Comparator;
|
|
|
|
/**
|
|
* 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
|
|
*/
|
|
/* Written using "Java Class Libraries", 2nd edition, plus online
|
|
* API docs for JDK 1.2 from http://www.javasoft.com.
|
|
* Status: Mostly complete, but parts stubbed out. Look for FIXME.
|
|
*/
|
|
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 str1 The first object to compare
|
|
* @param str2 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 obj1 The first object to compare
|
|
* @param obj2 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>The specified object is an instance of <code>Collator</code>.
|
|
* <li>The specified object has the same strength and decomposition
|
|
* settings as this object.
|
|
* </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 str1 The first <code>String</code> to compare
|
|
* @param str2 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 ()
|
|
{
|
|
// FIXME
|
|
Locale[] l = new Locale[1];
|
|
l[0] = Locale.US;
|
|
return l;
|
|
}
|
|
|
|
/**
|
|
* 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 str 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 locale The desired localed 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);
|
|
pattern = res.getString("collation_rules");
|
|
}
|
|
catch (MissingResourceException x)
|
|
{
|
|
return null;
|
|
}
|
|
try
|
|
{
|
|
return new RuleBasedCollator (pattern);
|
|
}
|
|
catch (ParseException x)
|
|
{
|
|
return null;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 decmp 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.
|
|
native final void decomposeCharacter (char c, StringBuffer buf);
|
|
|
|
/**
|
|
* This is the current collation decomposition setting.
|
|
*/
|
|
int decmp;
|
|
|
|
/**
|
|
* This is the current collation strength setting.
|
|
*/
|
|
int strength;
|
|
}
|