001// Copyright 2009, 2012 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.ComponentClasses;
019import org.apache.tapestry5.services.InvalidationEventHub;
020
021import javax.annotation.PostConstruct;
022
023import java.util.Map;
024
025public class StringInternerImpl implements StringInterner
026{
027    private final Map<String, String> cache = CollectionFactory.newConcurrentMap();
028
029    @PostConstruct
030    public void setupInvalidation(@ComponentClasses InvalidationEventHub hub)
031    {
032        hub.clearOnInvalidation(cache);
033    }
034
035    public String intern(String string)
036    {
037        String result = cache.get(string);
038
039        // Not yet in the cache?  Add it.
040
041        if (result == null)
042        {
043            cache.put(string, string);
044            result = string;
045        }
046
047        return result;
048    }
049
050    public String format(String format, Object... arguments)
051    {
052        return intern(String.format(format, arguments));
053    }
054}