com.hazelcast.map.impl.nearcache.NearCacheRecord 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.map.impl.nearcache;
import com.hazelcast.config.EvictionPolicy;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.util.Clock;
import com.hazelcast.util.QuickMath;
import java.util.Comparator;
import java.util.concurrent.atomic.AtomicLong;
/**
* Entry holder to be used in Client and Node side Near cache
*/
public class NearCacheRecord {
private static final Comparator LRU_COMPARATOR = new Comparator() {
public int compare(NearCacheRecord o1, NearCacheRecord o2) {
final int result = QuickMath.compareLongs(o1.lastAccessTime, o2.lastAccessTime);
if (result != 0) {
return result;
}
return QuickMath.compareIntegers(o1.key.hashCode(), o2.key.hashCode());
}
};
private static final Comparator LFU_COMPARATOR = new Comparator() {
public int compare(NearCacheRecord o1, NearCacheRecord o2) {
final int result = QuickMath.compareLongs(o1.hit.get(), o2.hit.get());
if (result != 0) {
return result;
}
return QuickMath.compareIntegers(o1.key.hashCode(), o2.key.hashCode());
}
};
private static final Comparator DEFAULT_COMPARATOR = new Comparator() {
public int compare(NearCacheRecord o1, NearCacheRecord o2) {
return QuickMath.compareIntegers(o1.key.hashCode(), o2.key.hashCode());
}
};
private final Object key;
private final Object value;
private final long creationTime;
private final AtomicLong hit;
private volatile long lastAccessTime;
public NearCacheRecord(Object key, Object value) {
assert key != null;
assert value != null;
this.key = key;
this.value = value;
long time = Clock.currentTimeMillis();
this.lastAccessTime = time;
this.creationTime = time;
this.hit = new AtomicLong();
}
public Object getKey() {
return key;
}
public Object getValue() {
return value;
}
public void access() {
hit.incrementAndGet();
lastAccessTime = Clock.currentTimeMillis();
}
public long getCost() {
// todo find object size if not a Data instance.
if (!(value instanceof Data)) {
return 0;
}
if (!(key instanceof Data)) {
return 0;
}
// value is Data
return ((Data) key).getHeapCost()
+ ((Data) value).getHeapCost()
+ 2 * (Long.SIZE / Byte.SIZE)
// sizeof atomic long
+ (Long.SIZE / Byte.SIZE)
// object references (key, value, hit)
+ 3 * (Integer.SIZE / Byte.SIZE);
}
public boolean isExpired(long maxIdleMillis, long timeToLiveMillis) {
long time = Clock.currentTimeMillis();
return (maxIdleMillis > 0 && time > lastAccessTime + maxIdleMillis)
|| (timeToLiveMillis > 0 && time > creationTime + timeToLiveMillis);
}
/**
* @param evictionPolicy EvictionPolicy
* @return appropriate comparator function depending on the eviction policy
*/
public static Comparator getComparator(EvictionPolicy evictionPolicy) {
if (EvictionPolicy.LRU.equals(evictionPolicy)) {
return NearCacheRecord.LRU_COMPARATOR;
} else if (EvictionPolicy.LFU.equals(evictionPolicy)) {
return NearCacheRecord.LFU_COMPARATOR;
} else {
return NearCacheRecord.DEFAULT_COMPARATOR;
}
}
}