Glassfish example source code file (StringManager.java)

This example Glassfish source code file (StringManager.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Glassfish tags/keywords

classloader, hashtable, illegalargumentexception, locale, missingresourceexception, object, object, resourcebundle, string, string, stringbuilder, stringbuilder, stringmanager, stringmanager, text, util

The Glassfish StringManager.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 *
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.tomcat.util.res;

import java.text.MessageFormat;
import java.util.*;

/**
 * An internationalization / localization helper class which reduces
 * the bother of handling ResourceBundles and takes care of the
 * common cases of message formating which otherwise require the
 * creation of Object arrays and such.
 *
 * <p>The StringManager operates on a package basis. One StringManager
 * per package can be created and accessed via the getManager method
 * call.
 *
 * <p>The StringManager will look for a ResourceBundle named by
 * the package name given plus the suffix of "LocalStrings". In
 * practice, this means that the localized information will be contained
 * in a LocalStrings.properties file located in the package
 * directory of the classpath.
 *
 * <p>Please see the documentation for java.util.ResourceBundle for
 * more information.
 *
 * @version $Revision: 1.3 $ $Date: 2007/05/05 05:33:17 $
 *
 * @author James Duncan Davidson [duncan@eng.sun.com]
 * @author James Todd [gonzo@eng.sun.com]
 * @author Mel Martinez [mmartinez@g1440.com]
 * @see java.util.ResourceBundle
 */

public class StringManager {

    /**
     * The ResourceBundle for this StringManager.
     */

    private volatile ResourceBundle bundle;

    private String packageName;
    private Locale locale;
    private ClassLoader classLoader;

    /**
     * Creates a new StringManager for a given package. This is a
     * private method and all access to it is arbitrated by the
     * static getManager method call so that only one StringManager
     * per package will be created.
     *
     * @param packageName Name of package to create StringManager for.
     */

    private StringManager(String packageName) {
	this( packageName, Locale.getDefault() );
    }

    private StringManager(String packageName,Locale loc) {
        this.packageName = packageName;
        this.locale = loc;
        this.classLoader = Thread.currentThread().getContextClassLoader();
    }

    private ResourceBundle getResourceBundle() {
        if(bundle!=null)    return bundle;

        String bundleName = packageName + ".LocalStrings";
        try {
            bundle = ResourceBundle.getBundle(bundleName,locale,classLoader);
        } catch( MissingResourceException ex ) {
            bundle= ResourceBundle.getBundle( bundleName,Locale.US,classLoader);
        }
        return bundle;
    }

    private StringManager(ResourceBundle bundle )
    {
	this.bundle=bundle;
    }

    /**
        Get a string from the underlying resource bundle or return
        null if the String is not found.
     
        @param key to desired resource String
        @return resource String matching <i>key from underlying
                bundle or null if not found.
        @throws IllegalArgumentException if <i>key is null.        
     */

    public String getString(String key) {
        if(key == null){
            String msg = "key may not have a null value";

            throw new IllegalArgumentException(msg);
        }

        String str = null;

        try{
            str = getResourceBundle().getString(key);
        }catch(MissingResourceException mre){
            //bad: shouldn't mask an exception the following way:
            //   str = "[cannot find message associated with key '" + key + "' due to " + mre + "]";
	        //     because it hides the fact that the String was missing
	        //     from the calling code.
	        //good: could just throw the exception (or wrap it in another)
	        //      but that would probably cause much havoc on existing
	        //      code.
	        //better: consistent with container pattern to
	        //      simply return null.  Calling code can then do
	        //      a null check.
	        str = null;
        }

        return str;
    }

    /**
     * Get a string from the underlying resource bundle and format
     * it with the given set of arguments.
     *
     * @param key
     * @param args
     */

    public String getString(String key, Object[] args) {
        String iString = null;
        String value = getString(key);

        // this check for the runtime exception is some pre 1.1.6
        // VM's don't do an automatic toString() on the passed in
        // objects and barf out

        try {
            // ensure the arguments are not null so pre 1.2 VM's don't barf
            if(args==null){
                args = new Object[1];
            }
            
            Object[] nonNullArgs = args;
            for (int i=0; i<args.length; i++) {
                if (args[i] == null) {
                    if (nonNullArgs==args){
                        nonNullArgs=(Object[])args.clone();
                    }
                    nonNullArgs[i] = "null";
                }
            }
            if( value==null ) value=key;
            iString = MessageFormat.format(value, nonNullArgs);
        } catch (IllegalArgumentException iae) {
            StringBuilder buf = new StringBuilder();
            buf.append(value);
            for (int i = 0; i < args.length; i++) {
                buf.append(" arg[" + i + "]=" + args[i]);
            }
            iString = buf.toString();
        }
        return iString;
    }

    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object argument. This argument can of course be
     * a String object.
     *
     * @param key
     * @param arg
     */

    public String getString(String key, Object arg) {
	Object[] args = new Object[] {arg};
	return getString(key, args);
    }

    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object arguments. These arguments can of course
     * be String objects.
     *
     * @param key
     * @param arg1
     * @param arg2
     */

    public String getString(String key, Object arg1, Object arg2) {
	Object[] args = new Object[] {arg1, arg2};
	return getString(key, args);
    }
    
    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object arguments. These arguments can of course
     * be String objects.
     *
     * @param key
     * @param arg1
     * @param arg2
     * @param arg3
     */

    public String getString(String key, Object arg1, Object arg2,
			    Object arg3) {
	Object[] args = new Object[] {arg1, arg2, arg3};
	return getString(key, args);
    }

    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object arguments. These arguments can of course
     * be String objects.
     *
     * @param key
     * @param arg1
     * @param arg2
     * @param arg3
     * @param arg4
     */

    public String getString(String key, Object arg1, Object arg2,
			    Object arg3, Object arg4) {
	Object[] args = new Object[] {arg1, arg2, arg3, arg4};
	return getString(key, args);
    }
    // --------------------------------------------------------------
    // STATIC SUPPORT METHODS
    // --------------------------------------------------------------

    private static Hashtable managers = new Hashtable();

    /**
     * Get the StringManager for a particular package. If a manager for
     * a package already exists, it will be reused, else a new
     * StringManager will be created and returned.
     *
     * @param packageName
     */

    public synchronized static StringManager getManager(String packageName) {
      StringManager mgr = (StringManager)managers.get(packageName);
      if (mgr == null) {
          mgr = new StringManager(packageName);
          managers.put(packageName, mgr);
      }
      return mgr;
    }

    /**
     * Get the StringManager for a particular package. If a manager for
     * a package already exists, it will be reused, else a new
     * StringManager will be created and returned.
     */
    public synchronized static StringManager getManager(ResourceBundle bundle) {
      return new StringManager( bundle );
    }

    /**
     * Get the StringManager for a particular package and Locale. If a manager for
     * a package already exists, it will be reused, else a new
     * StringManager will be created for that Locale and returned.
     *
     *
     * @param packageName
     */

   public synchronized static StringManager getManager(String packageName,Locale loc) {
      StringManager mgr = (StringManager)managers.get(packageName+"_"+loc.toString());
      if (mgr == null) {
          mgr = new StringManager(packageName,loc);
          managers.put(packageName+"_"+loc.toString(), mgr);
      }
      return mgr;
    }

}