Mega Code Archive
Cache LRU
<![CDATA[
/*
* Copyright (c) 2009, TamaCat.org
* All rights reserved.
*/
//package org.tamacat.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Set;
public class CacheLRU<K,V> {
private int maxSize;
private LinkedHashMap<K, V> cache;
private ArrayList<K> used;
public CacheLRU(int maxSize) {
this.maxSize = maxSize;
this.cache = new LinkedHashMap<K,V>(maxSize);
this.used = new ArrayList<K>(maxSize);
}
public CacheLRU() {
this(10);
}
public synchronized V get(K key) {
updateUsed(key);
return cache.get(key);
}
public synchronized V put(K key, V value) {
if (cache.size() >= maxSize && used.size() > 0) {
cache.remove(used.get(0));
used.remove(0);
}
updateUsed(key);
return cache.put(key, value);
}
private void updateUsed(K key) {
used.remove(key);
used.add(key);
}
public synchronized int size() {
return cache.size();
}
public synchronized V remove(K key) {
used.remove(key);
return cache.remove(key);
}
public synchronized void clear() {
cache.clear();
used.clear();
}
public Set<K> keySet() {
return cache.keySet();
}
public Collection<V> values() {
return cache.values();
}
@Override
public String toString() {
return getClass().getName() + "@" + hashCode() + "" + cache.toString();
}
}
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/*
* Copyright (c) 2009, TamaCat.org
* All rights reserved.
*/
package org.tamacat.util;
import static org.junit.Assert.*;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
public class CacheLRUTest {
@Before
public void setUp() throws Exception {
}
@After
public void tearDown() throws Exception {
}
@Test
public void testGet() {
int maxSize = 3;
CacheLRU<String,String> cache = new CacheLRU<String,String>(maxSize);
cache.put("1", "1");
cache.put("2", "2");
cache.put("3", "3");
assertEquals(maxSize, cache.size());
//cache.get("2");
//cache.get("1");
//System.out.println(cache.toString());
cache.put("4", "4");
cache.put("5", "5");
//System.out.println(cache.toString());
assertEquals(maxSize, cache.size());
}
}
]]>