com.hazelcast.mapreduce.impl.task.KeyValueSourceMappingPhase Maven / Gradle / Ivy

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/*
 * Copyright (c) 2008-2016, 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.impl.task;

import com.hazelcast.mapreduce.Context;
import com.hazelcast.mapreduce.KeyPredicate;
import com.hazelcast.mapreduce.KeyValueSource;
import com.hazelcast.mapreduce.Mapper;

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

/**
 * This class executes the mapping phase for a given {@link com.hazelcast.mapreduce.KeyValueSource} scope.
 *
 * @param     type of the input key
 * @param   type of the input value
 * @param    type of the emitted key
 * @param  type of the emitted value
 */
public class KeyValueSourceMappingPhase
        extends MappingPhase {

    public KeyValueSourceMappingPhase(Collection keys, KeyPredicate predicate) {
        super(keys, predicate);
    }

    @Override
    public void executeMappingPhase(KeyValueSource keyValueSource,
                                    Mapper mapper, Context context) {

        while (keyValueSource.hasNext()) {
            if (matches(keyValueSource.key())) {
                Map.Entry entry = keyValueSource.element();
                mapper.map(entry.getKey(), entry.getValue(), context);
            }
            if (isCancelled()) {
                return;
            }
        }
    }
}