/*

* 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);

}

}