com.datasalt.pangool.tuplemr.mapred.lib.input.DelegatingRecordReader.java Source code

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Here is the source code for com.datasalt.pangool.tuplemr.mapred.lib.input.DelegatingRecordReader.java

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/**
 * Copyright [2012] [Datasalt Systems S.L.]
 *
 * 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.datasalt.pangool.tuplemr.mapred.lib.input;

import java.io.IOException;

import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;

import com.datasalt.pangool.utils.InstancesDistributor;

/**
 * This is a delegating RecordReader, which delegates the functionality to the
 * underlying record reader in {@link TaggedInputSplit}
 */
public class DelegatingRecordReader<K, V> extends RecordReader<K, V> {
    RecordReader<K, V> originalRecordReader;

    /**
     * Constructs the DelegatingRecordReader.
     * 
     * @param split
     *          TaggegInputSplit object
     * @param context
     *          TaskAttemptContext object
     * 
     * @throws IOException
     * @throws InterruptedException
     */
    @SuppressWarnings("unchecked")
    public DelegatingRecordReader(InputSplit split, TaskAttemptContext context)
            throws IOException, InterruptedException {
        // Find the InputFormat and then the RecordReader from the
        // TaggedInputSplit.
        TaggedInputSplit taggedInputSplit = (TaggedInputSplit) split;
        InputFormat<K, V> inputFormat = (InputFormat<K, V>) InstancesDistributor.loadInstance(
                context.getConfiguration(), InputFormat.class, taggedInputSplit.getInputFormatFile(), true);
        PangoolMultipleInputs.setSpecificInputContext(context.getConfiguration(),
                taggedInputSplit.getInputFormatFile());
        originalRecordReader = inputFormat.createRecordReader(taggedInputSplit.getInputSplit(), context);
    }

    @Override
    public void close() throws IOException {
        originalRecordReader.close();
    }

    @Override
    public K getCurrentKey() throws IOException, InterruptedException {
        return originalRecordReader.getCurrentKey();
    }

    @Override
    public V getCurrentValue() throws IOException, InterruptedException {
        return originalRecordReader.getCurrentValue();
    }

    @Override
    public float getProgress() throws IOException, InterruptedException {
        return originalRecordReader.getProgress();
    }

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        TaggedInputSplit taggedInputSplit = (TaggedInputSplit) split;
        PangoolMultipleInputs.setSpecificInputContext(context.getConfiguration(),
                taggedInputSplit.getInputFormatFile());
        originalRecordReader.initialize(((TaggedInputSplit) split).getInputSplit(), context);
    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
        return originalRecordReader.nextKeyValue();
    }

}