com.hazelcast.internal.eviction.impl.evaluator.LFUEvictionPolicyEvaluator Maven / Gradle / Ivy

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/*
 * 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.impl.evaluator;

import com.hazelcast.internal.eviction.Evictable;

/**
 * Interface for evaluation implementations of {@link com.hazelcast.config.EvictionPolicy#LFU} policy.
 */
public class LFUEvictionPolicyEvaluator
        extends AbstractEvictionPolicyEvaluator {

    @Override
    protected Evictable selectEvictableAsPolicy(Evictable current, Evictable candidate) {
        int candidateAccessHit = candidate.getAccessHit();
        int currentAccessHit = current.getAccessHit();
        if (candidateAccessHit < currentAccessHit) {
            return candidate;
        } else if (currentAccessHit < candidateAccessHit) {
            return current;
        } else {
            // If access times are same, we select the oldest entry to evict
            if (candidate.getCreationTime() < current.getCreationTime()) {
                return candidate;
            } else {
                return current;
            }
        }
    }

}