com.hazelcast.internal.nearcache.impl.invalidation.StaleReadDetector Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2024, 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.nearcache.impl.invalidation;
import com.hazelcast.internal.nearcache.NearCacheRecord;
/**
* Used to detect staleness of Near Cache data.
*
* During {@link com.hazelcast.internal.nearcache.NearCache#get(Object)}, if one or more invalidations are lost for a key,
* we will make near cached data unreachable with the help of {@link StaleReadDetector} and next {@code get()} from the
* Near Cache will return {@code null} to force fresh data fetching from underlying IMap/ICache.
*
* @see com.hazelcast.internal.nearcache.impl.store.AbstractNearCacheRecordStore#get
*/
public interface StaleReadDetector {
/**
* This instance will be used when Near Cache invalidations are disabled.
* It behaves as if there is no stale data and everything is fresh.
*/
StaleReadDetector ALWAYS_FRESH = new StaleReadDetector() {
@Override
public boolean isStaleRead(Object key, NearCacheRecord record) {
return false;
}
@Override
public int getPartitionId(Object key) {
return 0;
}
@Override
public MetaDataContainer getMetaDataContainer(int partitionId) {
return null;
}
@Override
public String toString() {
return "ALWAYS_FRESH";
}
};
/**
* @param key the key
* @param record the Near Cache record
* @return {@code true} if reading with the supplied invalidation metadata is stale,
* otherwise returns {@code false}
*/
boolean isStaleRead(Object key, NearCacheRecord record);
int getPartitionId(Object key);
/**
* @param partitionId supplied partition ID to get value
* @return {@link MetaDataContainer} for this key
*/
MetaDataContainer getMetaDataContainer(int partitionId);
}