org.apache.tez.mapreduce.partition.MRPartitioner.java Source code

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Here is the source code for org.apache.tez.mapreduce.partition.MRPartitioner.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.tez.mapreduce.partition;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.util.ReflectionUtils;
import org.apache.tez.common.TezRuntimeFrameworkConfigs;
import org.apache.tez.mapreduce.hadoop.MRJobConfig;
import org.apache.tez.runtime.library.api.Partitioner;
import org.apache.tez.runtime.library.common.ConfigUtils;

/**
 * Provides an implementation of {@link Partitioner} that is compatible
 * with Map Reduce partitioners. 
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
@Public
public class MRPartitioner implements org.apache.tez.runtime.library.api.Partitioner {

    static final Log LOG = LogFactory.getLog(MRPartitioner.class);

    private final boolean useNewApi;

    private final org.apache.hadoop.mapreduce.Partitioner newPartitioner;
    private final org.apache.hadoop.mapred.Partitioner oldPartitioner;

    public MRPartitioner(Configuration conf) {
        this.useNewApi = ConfigUtils.useNewApi(conf);
        int partitions = conf.getInt(TezRuntimeFrameworkConfigs.TEZ_RUNTIME_NUM_EXPECTED_PARTITIONS, 1);

        if (useNewApi) {
            oldPartitioner = null;
            if (partitions > 1) {
                newPartitioner = (org.apache.hadoop.mapreduce.Partitioner) ReflectionUtils
                        .newInstance((Class<? extends org.apache.hadoop.mapreduce.Partitioner<?, ?>>) conf.getClass(
                                MRJobConfig.PARTITIONER_CLASS_ATTR,
                                org.apache.hadoop.mapreduce.lib.partition.HashPartitioner.class), conf);
            } else {
                newPartitioner = new org.apache.hadoop.mapreduce.Partitioner() {
                    @Override
                    public int getPartition(Object key, Object value, int numPartitions) {
                        return numPartitions - 1;
                    }
                };
            }
        } else {
            newPartitioner = null;
            if (partitions > 1) {
                oldPartitioner = (org.apache.hadoop.mapred.Partitioner) ReflectionUtils.newInstance(
                        (Class<? extends org.apache.hadoop.mapred.Partitioner>) conf.getClass(
                                "mapred.partitioner.class", org.apache.hadoop.mapred.lib.HashPartitioner.class),
                        new JobConf(conf));
            } else {
                oldPartitioner = new org.apache.hadoop.mapred.Partitioner() {
                    @Override
                    public void configure(JobConf job) {
                    }

                    @Override
                    public int getPartition(Object key, Object value, int numPartitions) {
                        return numPartitions - 1;
                    }
                };
            }
        }
    }

    @Override
    public int getPartition(Object key, Object value, int numPartitions) {
        if (useNewApi) {
            return newPartitioner.getPartition(key, value, numPartitions);
        } else {
            return oldPartitioner.getPartition(key, value, numPartitions);
        }
    }
}