/** * Copyright (c) 2002-2013 "Neo Technology," * Network Engine for Objects in Lund AB [http://neotechnology.com] * * This file is part of Neo4j. * * Neo4j is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.neo4j.kernel.impl.cache; import java.lang.ref.ReferenceQueue; import java.lang.ref.SoftReference; import java.util.HashMap; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; public class SoftLruCache<K,V> extends ReferenceCache<K,V> { private final ConcurrentHashMap<K,SoftValue<K,V>> cache = new ConcurrentHashMap<K,SoftValue<K,V>>(); private final SoftReferenceQueue<K,V> refQueue = new SoftReferenceQueue<K,V>(); private final String name; public SoftLruCache( String name ) { this.name = name; } public void put( K key, V value ) { SoftValue<K,V> ref = new SoftValue<K,V>( key, value, (ReferenceQueue<V>) refQueue ); cache.put( key, ref ); pollClearedValues(); } public void putAll( Map<K,V> map ) { Map<K,SoftValue<K,V>> softMap = new HashMap<K,SoftValue<K,V>>( map.size() * 2 ); for ( Map.Entry<K, V> entry : map.entrySet() ) { SoftValue<K,V> ref = new SoftValue<K,V>( entry.getKey(), entry.getValue(), (ReferenceQueue<V>) refQueue ); softMap.put( entry.getKey(), ref ); } cache.putAll( softMap ); pollClearedValues(); } public V get( K key ) { SoftReference<V> ref = cache.get( key ); if ( ref != null ) { if ( ref.get() == null ) { cache.remove( key ); } return counter.count( ref.get() ); } return counter.<V>count( null ); } public V remove( K key ) { SoftReference<V> ref = cache.remove( key ); if ( ref != null ) { return ref.get(); } return null; } @Override protected void pollClearedValues() { SoftValue<K,V> clearedValue = refQueue.safePoll(); while ( clearedValue != null ) { cache.remove( clearedValue.key ); clearedValue = refQueue.safePoll(); } } public int size() { return cache.size(); } public void clear() { cache.clear(); } public void elementCleaned( V value ) { } public String getName() { return name; } private final HitCounter counter = HitCounter.create(); @Override public long hitCount() { return counter.getHitsCount(); } @Override public long missCount() { return counter.getMissCount(); } public boolean isAdaptive() { return true; } public int maxSize() { return -1; } public void resize( int newSize ) { } public void setAdaptiveStatus( boolean status ) { } }