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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
* <p/>
* http://www.apache.org/licenses/LICENSE-2.0
* <p/>
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* KIND, either express or implied. See the License for the
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package org.apache.sling.scripting.core.impl.helper;
import java.lang.ref.SoftReference;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* <p>
* The {@code CachingMap} class offers an implementation of a {@link LinkedHashMap} that can be used for caches. The maps' values are
* {@link SoftReference}s, such that garbage collection can be performed on the cache, if needed.
* </p>
* <p>
* Read / write operations are <i>NOT</i> synchronised.
* </p>
*
* @param <T> the type to which {@link SoftReference}s will be kept
*/
public class CachingMap<T> extends LinkedHashMap<String, SoftReference<T>> {
private int capacity;
/**
* Creates a caching map with a maximum capacity equal to the {@code capacity} parameter.
*
* @param capacity the maximum capacity; if {@code capacity < 1} then this map will always remove the latest added element
*/
public CachingMap(int capacity) {
this.capacity = capacity;
}
@Override
protected boolean removeEldestEntry(Map.Entry<String, SoftReference<T>> eldest) {
return size() > capacity;
}
}