com.hazelcast.map.impl.eviction.Evictor Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2018, 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.eviction;
import com.hazelcast.map.impl.recordstore.RecordStore;
import com.hazelcast.nio.serialization.Data;
import static java.lang.Integer.getInteger;
/**
* Evicts a {@link RecordStore}.
*
* When the {@link RecordStore} needs to be evicted according to {@link Evictor#checkEvictable},
* {@link Evictor} removes records from {@link RecordStore}.
*/
public interface Evictor {
Evictor NULL_EVICTOR = new Evictor() {
@Override
public void evict(RecordStore recordStore, Data excludedKey) {
}
@Override
public boolean checkEvictable(RecordStore recordStore) {
return false;
}
};
String SYSTEM_PROPERTY_SAMPLE_COUNT = "hazelcast.map.eviction.sample.count";
int DEFAULT_SAMPLE_COUNT = 15;
int SAMPLE_COUNT = getInteger(SYSTEM_PROPERTY_SAMPLE_COUNT, DEFAULT_SAMPLE_COUNT);
/**
* Evict supplied record-store.
*
* @param recordStore the recordStore
* @param excludedKey this key has lowest priority to be selected for eviction and it is nullable.
*/
void evict(RecordStore recordStore, Data excludedKey);
/**
* Check whether the supplied record-store needs eviction.
*
* @param recordStore the recordStore
* @return {@code true} if eviction is required, {@code false} otherwise.
*/
boolean checkEvictable(RecordStore recordStore);
}