/*
 * Copyright (c) 2008-2017, 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.mapstore;

import java.util.Collection;
import java.util.Map;

/**
 * Map data stores general contract.
 * Provides an extra abstraction layer over write-through and write-behind map-store implementations.
 *
 * @param <K> type of key to store.
 * @param <V> type of value to store.
 */
public interface MapDataStore<K, V> {

    V add(K key, V value, long now);

    void addTransient(K key, long now);

    V addBackup(K key, V value, long now);

    void remove(K key, long now);

    void removeBackup(K key, long now);

    /**
     * Returns all associated resources of this map-data-store back to the initial state.
     */
    void reset();

    V load(K key);

    Map loadAll(Collection keys);

    /**
     * Removes keys from map store.
     * It also handles {@link com.hazelcast.nio.serialization.Data} to object conversions of keys.
     *
     * @param keys to be removed.
     */
    void removeAll(Collection keys);

    boolean loadable(K key);

    int notFinishedOperationsCount();

    boolean isPostProcessingMapStore();

    /**
     * Only marks this {@link MapDataStore} as flush-able. Flush means storing entries from write-behind-queue into map-store
     * regardless of the scheduled store-time. Actual flushing is done by another thread than partition-operation thread
     * which runs {@link com.hazelcast.map.impl.mapstore.writebehind.StoreWorker}.
     *
     * @return last given sequence number to the last store operation
     * @see com.hazelcast.map.impl.operation.MapFlushOperation
     */
    long softFlush();

    /**
     * Flushes write-behind-queue into map-store in calling thread.
     * <p/>
     * After calling of this method, all elements in the {@link com.hazelcast.map.impl.mapstore.writebehind.WriteBehindQueue}
     * of this {@link MapDataStore} should be in map-store regardless of the scheduled store-time.
     * <p/>
     * The only call to this method is in node-shutdown.
     *
     * @see com.hazelcast.map.impl.MapManagedService#shutdown(boolean)
     */
    void hardFlush();

    /**
     * Flushes the supplied key to the map-store.
     *
     * @param key    key to be flushed
     * @param value  value to be flushed
     * @param backup <code>true</code> calling this method for backup partition, <code>false</code> for owner partition.
     * @return flushed value.
     */
    V flush(K key, V value, boolean backup);
}