Tutorial6.java

/*
 * Copyright (c) 2008-2013, 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 tutorials;

import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.IMap;
import com.hazelcast.mapreduce.Collator;
import com.hazelcast.mapreduce.Job;
import com.hazelcast.mapreduce.JobCompletableFuture;
import com.hazelcast.mapreduce.JobTracker;
import com.hazelcast.mapreduce.KeyValueSource;
import model.SalaryYear;
import tutorials.impl.SalarySumCombinerFactory;
import tutorials.impl.SalarySumMapper;
import tutorials.impl.SalarySumReducerFactory;

import java.util.Map;

public class Tutorial6 implements Tutorial {

    @Override
    public void execute(HazelcastInstance hazelcastInstance) throws Exception {
        JobTracker jobTracker = hazelcastInstance.getJobTracker("default");

        IMap<String, SalaryYear> map = hazelcastInstance.getMap("salaries");
        KeyValueSource<String, SalaryYear> source = KeyValueSource.fromMap(map);

        Job<String, SalaryYear> job = jobTracker.newJob(source);

        JobCompletableFuture<Integer> future = job
                .mapper(new SalarySumMapper())
                .combiner(new SalarySumCombinerFactory())
                .reducer(new SalarySumReducerFactory())
                .submit(new SalarySumCollator());

        System.out.println("Salary sum: " + future.get());
    }

    private static class SalarySumCollator implements Collator<Map.Entry<String, Integer>, Integer> {

        @Override
        public Integer collate(Iterable<Map.Entry<String, Integer>> values) {
            int sum = 0;
            for (Map.Entry<String, Integer> value : values) {
                sum += value.getValue();
            }
            return sum;
        }
    }
}