com.skp.experiment.common.mapreduce.IdentityMapper.java Source code

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Here is the source code for com.skp.experiment.common.mapreduce.IdentityMapper.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 com.skp.experiment.common.mapreduce;

import java.io.IOException;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.Mapper;

public class IdentityMapper<K, V> extends Mapper<K, V, K, V> {
    public static String VALUE_ONLY_OUT = IdentityMapper.class.getName() + ".valueOnlyOut";
    public static String KEY_ONLY_OUT = IdentityMapper.class.getName() + ".keyOnlyOut";
    private static boolean valueOnlyOut = false;
    private static boolean keyOnlyOut = false;

    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
        valueOnlyOut = context.getConfiguration().getBoolean(VALUE_ONLY_OUT, false);
        keyOnlyOut = context.getConfiguration().getBoolean(KEY_ONLY_OUT, false);
    }

    @SuppressWarnings("unchecked")
    @Override
    protected void map(K key, V value, Context context) throws IOException, InterruptedException {
        if (valueOnlyOut) {
            context.write((K) NullWritable.get(), value);
        } else if (keyOnlyOut) {
            context.write(key, (V) NullWritable.get());
        } else {
            context.write(key, value);
        }
    }

}