001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.util;
016    
017    import java.util.MissingResourceException;
018    import java.util.ResourceBundle;
019    
020    import org.apache.tapestry.engine.IPropertySource;
021    
022    /**
023     *  A property source that is based on a {@link java.util.ResourceBundle}.
024     *
025     *  @author Howard Lewis Ship
026     *  @since 3.0
027     *
028     **/
029    
030    public class ResourceBundlePropertySource implements IPropertySource
031    {
032        private ResourceBundle _bundle;
033    
034        public ResourceBundlePropertySource(ResourceBundle bundle)
035        {
036            _bundle = bundle;
037        }
038    
039        /**
040         *  Gets the value from the bundle by invoking
041         *  {@link ResourceBundle#getString(java.lang.String)}.  If
042         *  the bundle does not contain the key (that is, it it
043         *  throws {@link java.util.MissingResourceException}), then
044         *  null is returned.
045         * 
046         **/
047        
048        public String getPropertyValue(String propertyName)
049        {
050            try
051            {
052                return _bundle.getString(propertyName);
053            }
054            catch (MissingResourceException ex)
055            {
056                return null;
057            }
058        }
059    
060    }