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Redis Java client with features of In-Memory Data Grid
/**
* Copyright (c) 2013-2022 Nikita Koksharov
*
* 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 org.redisson.cache;
import java.util.*;
import java.util.concurrent.atomic.AtomicLong;
/**
* LRU (least recently used) cache.
*
* @author Nikita Koksharov
*
* @param key
* @param value
*/
public class LRUCacheMap extends AbstractCacheMap {
private final AtomicLong index = new AtomicLong();
private final List>> queues =
new ArrayList>>();
public LRUCacheMap(int size, long timeToLiveInMillis, long maxIdleInMillis) {
super(size, timeToLiveInMillis, maxIdleInMillis);
for (int i = 0; i < Runtime.getRuntime().availableProcessors()*2; i++) {
Set> instance = Collections.synchronizedSet(new LinkedHashSet>());
queues.add(instance);
}
}
@Override
protected void onValueCreate(CachedValue value) {
Collection> queue = getQueue(value);
queue.add(value);
}
private Collection> getQueue(CachedValue value) {
return queues.get(Math.abs(value.hashCode() % queues.size()));
}
@Override
protected void onValueRemove(CachedValue value) {
Collection> queue = getQueue(value);
queue.remove(value);
}
@Override
protected void onValueRead(CachedValue value) {
Collection> queue = getQueue(value);
// move value to tail of queue
if (queue.remove(value)) {
queue.add(value);
}
}
@Override
protected void onMapFull() {
int startIndex = -1;
while (true) {
int queueIndex = (int) Math.abs(index.incrementAndGet() % queues.size());
if (queueIndex == startIndex) {
return;
}
if (startIndex == -1) {
startIndex = queueIndex;
}
Collection> queue = queues.get(queueIndex);
CachedValue removedValue = null;
synchronized (queue) {
Iterator> iter = queue.iterator();
if (iter.hasNext()) {
removedValue = iter.next();
iter.remove();
}
}
if (removedValue != null) {
map.remove(removedValue.getKey(), removedValue);
return;
}
}
}
@Override
public void clear() {
for (Collection> collection : queues) {
collection.clear();
}
super.clear();
}
}