001    // Copyright 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.services.impl;
016    
017    import java.util.Locale;
018    
019    import org.apache.hivemind.util.Defense;
020    import org.apache.hivemind.util.LocalizedNameGenerator;
021    import org.apache.tapestry.engine.IPropertySource;
022    
023    /**
024     * Wraps around a {@link org.apache.tapestry.engine.IPropertySource}to query a series of localized
025     * keys.
026     * <p>
027     * This is much simpler than the old {@link LocalizedPropertySource}, and
028     * allows the locale to be specified on a thread-safe, per-invocation basis.
029     * 
030     * @author Howard M. Lewis Ship
031     * @since 4.0
032     */
033    public class LocalizedPropertySource
034    {
035        private IPropertySource _source;
036    
037        public LocalizedPropertySource(IPropertySource source)
038        {
039            Defense.notNull(source, "source");
040    
041            _source = source;
042        }
043    
044        /**
045         * Get the property from the source, trying different variations of propertyName (adding
046         * suffixes).
047         * 
048         * @param propertyName
049         *            the base property name to search with.
050         * @param locale
051         *            the Locale used to generate suffixes (may be null).
052         */
053    
054        public String getPropertyValue(String propertyName, Locale locale)
055        {
056            Defense.notNull(propertyName, "propertyName");
057    
058            LocalizedNameGenerator g = new LocalizedNameGenerator(propertyName, locale, "");
059    
060            while (g.more())
061            {
062                String localizedName = g.next();
063    
064                String result = _source.getPropertyValue(localizedName);
065    
066                if (result != null)
067                    return result;
068            }
069    
070            return null;
071        }
072    }