    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}