com.blazebit.persistence.parser.expression.ConcurrentHashMapExpressionCache Maven / Gradle / Ivy
/*
* Copyright 2014 - 2019 Blazebit.
*
* Licensed 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 com.blazebit.persistence.parser.expression;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
/**
*
* @author Christian Beikov
* @since 1.2.0
*/
public class ConcurrentHashMapExpressionCache implements ExpressionCache {
private final ConcurrentMap> cacheManager;
public ConcurrentHashMapExpressionCache() {
this.cacheManager = new ConcurrentHashMap<>();
}
@Override
public T get(String cacheName, Key key) {
final ConcurrentMap cache = cacheManager.get(cacheName);
return cache == null ? null : cache.get(key);
}
@Override
public T putIfAbsent(String cacheName, Key key, T value) {
// Find the cache manager
ConcurrentMap cache = cacheManager.get(cacheName);
if (cache == null) {
cache = new ConcurrentHashMap<>();
ConcurrentMap oldCache = cacheManager.putIfAbsent(cacheName, cache);
if (oldCache != null) {
cache = oldCache;
}
}
T oldValue = cache.putIfAbsent(key, value);
if (oldValue != null) {
return oldValue;
}
return value;
}
}