NearCacheRecordStore.java

/*
 * 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.internal.nearcache;

import com.hazelcast.internal.adapter.DataStructureAdapter;
import com.hazelcast.internal.nearcache.impl.invalidation.StaleReadDetector;
import com.hazelcast.monitor.NearCacheStats;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.spi.InitializingObject;

/**
 * {@link NearCacheRecordStore} is the contract point to store keys and values as
 * {@link NearCacheRecord} internally and to serve them.
 *
 * @param <K> the type of the key
 * @param <V> the type of the value
 */
public interface NearCacheRecordStore<K, V> extends InitializingObject {

    /**
     * Gets the value associated with the given {@code key}.
     *
     * @param key the key from which to get the associated value.
     * @return the value associated with the given {@code key}.
     */
    V get(K key);

    /**
     * Puts (associates) a value with the given {@code key}.
     *
     * @param key     the key to which the given value will be associated.
     * @param keyData the key as {@link Data} to which the given value will be associated.
     * @param value   the value that will be associated with the key.
     */
    void put(K key, Data keyData, V value);

    /**
     * Removes the value associated with the given {@code key}
     * and increases the invalidation statistics.
     *
     * @param key the key of the value will be invalidated
     */
    void invalidate(K key);

    /**
     * Removes all stored values.
     */
    void clear();

    /**
     * Clears the record store and destroys it.
     */
    void destroy();

    /**
     * Gets the number of stored records.
     *
     * @return the number of stored records.
     */
    int size();

    /**
     * Gets the record associated with the given {@code key}.
     *
     * @param key the key from which to get the associated {@link NearCacheRecord}.
     * @return the {@link NearCacheRecord} associated with the given {@code key}.
     */
    NearCacheRecord getRecord(K key);

    /**
     * Get the {@link com.hazelcast.monitor.NearCacheStats} instance to monitor this record store.
     *
     * @return the {@link com.hazelcast.monitor.NearCacheStats} instance to monitor this record store.
     */
    NearCacheStats getNearCacheStats();

    /**
     * Selects the best candidate object to store from the given {@code candidates}.
     *
     * @param candidates the candidates from which the best candidate object will be selected.
     * @return the best candidate object to store, selected from the given {@code candidates}.
     */
    Object selectToSave(Object... candidates);

    /**
     * Performs expiration and evicts expired records.
     */
    void doExpiration();

    /**
     * Does eviction as specified configuration {@link com.hazelcast.config.EvictionConfig}
     * in {@link com.hazelcast.config.NearCacheConfig}.
     */
    void doEvictionIfRequired();

    /**
     * Does eviction as specified configuration {@link com.hazelcast.config.EvictionConfig}
     * in {@link com.hazelcast.config.NearCacheConfig} regardless from the max-size policy.
     */
    void doEviction();

    /**
     * Loads the keys into the Near Cache.
     */
    void loadKeys(DataStructureAdapter<Object, ?> adapter);

    /**
     * Persists the key set of the Near Cache.
     */
    void storeKeys();

    /**
     * @see StaleReadDetector
     */
    void setStaleReadDetector(StaleReadDetector detector);

    /**
     * @see StaleReadDetector
     */
    StaleReadDetector getStaleReadDetector();

    long tryReserveForUpdate(K key, Data keyData);

    V tryPublishReserved(K key, V value, long reservationId, boolean deserialize);

    boolean isAvailable();
}