001// Copyright 2009 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
015package org.apache.tapestry5.internal.services;
016
017import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
018import org.apache.tapestry5.services.InvalidationListener;
019
020import java.util.Map;
021
022public class StringInternerImpl implements StringInterner, InvalidationListener
023{
024    private final Map<String, String> cache = CollectionFactory.newConcurrentMap();
025
026    public void objectWasInvalidated()
027    {
028        cache.clear();
029    }
030
031    public String intern(String string)
032    {
033        String result = cache.get(string);
034
035        // Not yet in the cache?  Add it.
036
037        if (result == null)
038        {
039            cache.put(string, string);
040            result = string;
041        }
042
043        return result;
044    }
045
046    public String format(String format, Object... arguments)
047    {
048        return intern(String.format(format, arguments));
049    }
050}