hazelcast-master/hazelcast/src/main/java/com/hazelcast/partition/PartitioningStrategy.java
/*
 * Copyright (c) 2008-2023, 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.partition;

import java.io.Serializable;

/**
 * PartitioningStrategy allows keys to be located on the same member.
 * This causes related data to be stored in the same location. (See data-affinity.)
 *
 * @param <K> key type
 */
@FunctionalInterface
public interface PartitioningStrategy<K> extends Serializable {

    /**
     * Returns the key object that will be used by Hazelcast to specify the partition.
     *
     * @param key actual key object used by Hazelcast to specify the partition
     * @return the partition key object, or null to fallback to the default partition calculation
     */
    Object getPartitionKey(K key);
}
