/*
* Copyright 2015 Ben Manes. 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.github.benmanes.caffeine.cache.simulator.policy.opt;
import java.util.Set;
import com.github.benmanes.caffeine.cache.simulator.policy.Policy;
import com.github.benmanes.caffeine.cache.simulator.policy.PolicyStats;
import com.google.common.collect.ImmutableSet;
import com.typesafe.config.Config;
import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
/**
* A cache that has no maximum size. This demonstrates the upper bound of the hit rate due to
* compulsory misses (first reference misses), which can only be avoided if the application can
* intelligently prefetch the data prior to the request.
*
* @author ben.manes@gmail.com (Ben Manes)
*/
public final class UnboundedPolicy implements Policy {
private final PolicyStats policyStats;
private final LongOpenHashSet data;
public UnboundedPolicy() {
this.policyStats = new PolicyStats("opt.Unbounded");
this.data = new LongOpenHashSet();
}
/** Returns all variations of this policy based on the configuration parameters. */
public static Set<Policy> policies(Config config) {
return ImmutableSet.of(new UnboundedPolicy());
}
@Override
public PolicyStats stats() {
return policyStats;
}
@Override
public void record(long key) {
policyStats.recordOperation();
if (data.add(key)) {
policyStats.recordMiss();
} else {
policyStats.recordHit();
}
}
}