/*******************************************************************************
* Copyright (c) 2000, 2011 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.corext.util;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* Least-recently-used cache. When the map tops the maximum size configured in the constructor, it
* automatically removes the oldest entry in terms of last access.
* <p>
* Invoking the <tt>put</tt> or <tt>get</tt> method results in an access to the corresponding entry.
* The <tt>putAll</tt> method generates one entry access for each mapping in the specified map, in
* the order that key-value mappings are provided by the specified map's entry set iterator. <i>No
* other methods generate entry accesses.</i> In particular, operations on collection-views do
* <i>not</i> affect the order of iteration of the backing map.
*
* @param <K> type of the keys
* @param <V> type of the values
*/
public class LRUMap<K,V> extends LinkedHashMap<K,V> {
private static final long serialVersionUID= 1L;
private final int fMaxSize;
/**
* Creates an empty LRU map with the given maximum size.
*
* @param maxSize the maximum number of elements in the cache
*/
public LRUMap(int maxSize) {
super(maxSize, 0.75f, true);
fMaxSize= maxSize;
}
@Override
protected boolean removeEldestEntry(Map.Entry<K,V> eldest) {
return size() > fMaxSize;
}
}