Groovy example source code file (LRUCache.java)

This example Groovy source code file (LRUCache.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

lrucache, lrucache, lruprotectionstorage, lruprotectionstorage, map, memoizecache, object, object, softreference, softreference, util

The Groovy LRUCache.java source code

package org.codehaus.groovy.runtime.memoize;

import java.lang.ref.SoftReference;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;

/**
 * A cache backed by a Collections.SynchronizedMap
 *
 * @author Vaclav Pech
 */
public final class LRUCache implements MemoizeCache<Object, Object> {

    private final Map<Object, Object> cache;

    public LRUCache(final int maxCacheSize) {
        cache = Collections.synchronizedMap(new LRUProtectionStorage(maxCacheSize));
    }

    public Object put(final Object key, final Object value) {
        return cache.put(key, value);
    }

    public Object get(final Object key) {
        return cache.get(key);
    }

    /**
     * Replying on the Collections.SynchronizedMap thread-safe iteration implementation the method will remove all entries holding
     * SoftReferences to gc-evicted objects.
     */
    public void cleanUpNullReferences() {
        synchronized (cache) {
            final Iterator<Map.Entry iterator = cache.entrySet().iterator();
            while (iterator.hasNext()) {
                final Map.Entry<Object, Object> entry = iterator.next();
                if (((SoftReference) entry.getValue()).get() == null) iterator.remove();
            }
        }
    }
}