/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.j2me.global;
import com.sun.midp.main.Configuration;
import com.sun.midp.log.Logging;
import com.sun.midp.log.LogChannels;
/**
* The <code>CollationAbstractionLayer</code> class provides a layer of
* abstraction for {@link javax.microedition.global.StringComparator}
* realization. Sub-classes of <code>CollationAbstractionLayer</code>
* correspond to individual implementations of string comparison.
*/
public abstract class CollationAbstractionLayer {
/**
* Constant name of collation abstraction layer class property.
*/
private final static String ABSTRACTION_LAYER_PROPERTY =
"microedition.global.collation.abstractionlayer";
/**
* Constant name of default collation abstraction layer class.
*/
private final static String DEFAULT_ABSTRACTION_LAYER =
"com.sun.j2me.global.CollationAbstractionLayerImpl";
/**
* An instance of <code>CollationAbstractionLayer</code>, which is
* used in the {@link #getInstance() getInstance} method.
*/
private static CollationAbstractionLayer abstractionLayer;
/**
* Returns an instance <code>CollationAbstractionLayer</code>. This
* instance is created only once (singleton) and then it is reused when
* the method is called again.
*
* @return the instance of the <code>AbstractionLayer</code> sub-class,
* <code>null</code> if unable to get sub-class instance
*/
public static CollationAbstractionLayer getInstance() {
if (abstractionLayer == null) {
String alClsName =
Configuration.getProperty(ABSTRACTION_LAYER_PROPERTY);
if (alClsName != null) {
try {
abstractionLayer = (CollationAbstractionLayer)
Class.forName(alClsName).newInstance();
} catch (ClassNotFoundException cnf_ignore) {
/* intentionally ignored */
if (Logging.REPORT_LEVEL <= Logging.WARNING) {
Logging.report(Logging.WARNING, LogChannels.LC_JSR238,
"default Collation handler class does not exist:"
+ alClsName);
}
} catch (InstantiationException ie_ignore) {
/* intentionally ignored */
if (Logging.REPORT_LEVEL <= Logging.WARNING) {
Logging.report(Logging.WARNING, LogChannels.LC_JSR238,
"default Collation handler class missing constructor:"
+ alClsName);
}
} catch (IllegalAccessException iae_ignore) {
/* intentionally ignored */
if (Logging.REPORT_LEVEL <= Logging.WARNING) {
Logging.report(Logging.WARNING, LogChannels.LC_JSR238,
"default Collation handler class incorrect type:"
+ alClsName);
}
}
}
if (abstractionLayer == null) {
// try default abstraction layer
try {
abstractionLayer = (CollationAbstractionLayer)Class.forName(
DEFAULT_ABSTRACTION_LAYER).newInstance();
} catch (ClassNotFoundException cnf_ignore) {
/* intentionally ignored */
if (Logging.REPORT_LEVEL <= Logging.WARNING) {
Logging.report(Logging.WARNING, LogChannels.LC_JSR238,
"Default Collation handler class does not exist:"
+ DEFAULT_ABSTRACTION_LAYER);
}
} catch (InstantiationException ie_ignore) {
/* intentionally ignored */
if (Logging.REPORT_LEVEL <= Logging.WARNING) {
Logging.report(Logging.WARNING, LogChannels.LC_JSR238,
"Collation handler class missing constructor:"
+ DEFAULT_ABSTRACTION_LAYER);
}
} catch (IllegalAccessException iae_ignore) {
/* intentionally ignored */
if (Logging.REPORT_LEVEL <= Logging.WARNING) {
Logging.report(Logging.WARNING, LogChannels.LC_JSR238,
"Collation handler class incorrect type:"
+ DEFAULT_ABSTRACTION_LAYER);
}
}
}
}
return abstractionLayer;
}
/**
* Returns an instance of the <code>StringComparator</code> sub-class,
* which realizes platform-specific <code>StringComparator</code> methods.
*
* @param locale the locale to use with this <code>StringComparator</code>
* @param level level of collation, as defined in {@link
* javax.microedition.global.StringComparator}
* @return the instance of the <code>StringComparator</code> realization
* @see CommonStringComparator
*/
public abstract CommonStringComparator getStringComparator(String locale,
int level);
/**
* Gets the locales for which a <code>StringComparator</code> is available
* in individual implementation. If no locales are supported, the returned
* array must be empty, not <code>null</code>. As the value
* <code>null</code> is not technically a valid locale, but a special value
* to trigger the generic collation algorithm, it must not appear in the
* array.
*
* @return an array of valid <code>microedition.locale</code> values
*/
public abstract String[] getSupportedLocales();
}
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