com.hazelcast.internal.eviction.EvictionPolicyEvaluatorProvider Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2016, Hazelcast, Inc. All Rights Reserved.
*
* 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.hazelcast.internal.eviction;
import com.hazelcast.internal.eviction.impl.comparator.LFUEvictionPolicyComparator;
import com.hazelcast.internal.eviction.impl.comparator.LRUEvictionPolicyComparator;
import com.hazelcast.internal.eviction.impl.evaluator.DefaultEvictionPolicyEvaluator;
import com.hazelcast.nio.ClassLoaderUtil;
import com.hazelcast.util.ExceptionUtil;
import com.hazelcast.util.StringUtil;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
/**
* Provider to get any kind ({@link EvictionPolicyType}) of {@link EvictionPolicyEvaluator}.
*/
public final class EvictionPolicyEvaluatorProvider {
private static final ConcurrentMap EVICTION_POLICY_COMPARATOR_MAP =
new ConcurrentHashMap();
private EvictionPolicyEvaluatorProvider() {
}
private static EvictionPolicyComparator createEvictionPolicyComparator(EvictionPolicyType evictionPolicyType) {
switch (evictionPolicyType) {
case LRU:
return new LRUEvictionPolicyComparator();
case LFU:
return new LFUEvictionPolicyComparator();
default:
throw new IllegalArgumentException("Unsupported eviction policy type: " + evictionPolicyType);
}
}
/**
* Gets the {@link EvictionPolicyEvaluator} implementation specified with evictionPolicy.
*
* @param evictionConfig {@link EvictionConfiguration} for requested {@link EvictionPolicyEvaluator} implementation
* @param classLoader the {@link java.lang.ClassLoader} to be used
* while creating custom {@link EvictionPolicyComparator} if it is specified in the config
*
* @return the requested {@link EvictionPolicyEvaluator} implementation
*/
public static EvictionPolicyEvaluator getEvictionPolicyEvaluator(EvictionConfiguration evictionConfig,
ClassLoader classLoader) {
if (evictionConfig == null) {
return null;
}
EvictionPolicyComparator evictionPolicyComparator = null;
String evictionPolicyComparatorClassName = evictionConfig.getComparatorClassName();
if (!StringUtil.isNullOrEmpty(evictionPolicyComparatorClassName)) {
try {
evictionPolicyComparator =
ClassLoaderUtil.newInstance(classLoader, evictionPolicyComparatorClassName);
} catch (Exception e) {
ExceptionUtil.rethrow(e);
}
} else {
EvictionPolicyComparator comparator = evictionConfig.getComparator();
if (comparator != null) {
evictionPolicyComparator = comparator;
} else {
EvictionPolicyType evictionPolicyType = evictionConfig.getEvictionPolicyType();
if (evictionPolicyType == null) {
return null;
}
evictionPolicyComparator = createEvictionPolicyComparator(evictionPolicyType);
}
}
return new DefaultEvictionPolicyEvaluator(evictionPolicyComparator);
}
}