com.hazelcast.mapreduce.KeyPredicate Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2015, 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.mapreduce;
import com.hazelcast.spi.annotation.Beta;
import java.io.Serializable;
/**
* This interface is used to pre-evaluate keys before spreading the MapReduce task to the cluster.
* Pre-selecting keys can speed up the job since not all partitions may be used.
*
* @param key type
* @since 3.2
*/
@Beta
public interface KeyPredicate
extends Serializable {
/**
* This method evaluates whether or not to select a key.
*
* @param key The key to evaluate
* @return true if the MapReduce task should be executed on this key, false otherwise
*/
boolean evaluate(Key key);
}