org.apache.myfaces.util.lang.LRULinkedHashMap Maven / Gradle / Ivy
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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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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*/
package org.apache.myfaces.util.lang;
import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.Map;
public class LRULinkedHashMap extends LinkedHashMap implements Serializable
{
private static final float DEFAULT_LOAD_FACTOR = 0.75f;
private final int capacity;
private SerializableConsumer> expiredCallback;
public LRULinkedHashMap(int capacity)
{
// 1 extra element as add happens before remove (101), and load factor big
// enough to avoid triggering resize. True = keep in access order.
super(capacity + 1, DEFAULT_LOAD_FACTOR, true);
this.capacity = capacity;
}
public LRULinkedHashMap(int capacity, SerializableConsumer> expiredCallback)
{
this(capacity);
this.expiredCallback = expiredCallback;
}
@Override
protected boolean removeEldestEntry(Map.Entry eldest)
{
boolean remove = size() > capacity;
if (remove && expiredCallback != null)
{
expiredCallback.accept(eldest);
}
return remove;
}
}