/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file 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 "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.el.util; import java.util.Map; import java.util.WeakHashMap; import java.util.concurrent.ConcurrentHashMap; public final class ConcurrentCache<K,V> { private final int size; private final Map<K,V> eden; private final Map<K,V> longterm; public ConcurrentCache(int size) { this.size = size; this.eden = new ConcurrentHashMap<>(size); this.longterm = new WeakHashMap<>(size); } public V get(K k) { V v = this.eden.get(k); if (v == null) { synchronized (longterm) { v = this.longterm.get(k); } if (v != null) { this.eden.put(k, v); } } return v; } public void put(K k, V v) { if (this.eden.size() >= size) { synchronized (longterm) { this.longterm.putAll(this.eden); } this.eden.clear(); } this.eden.put(k, v); } }