com.ambiata.ivory.operation.hadoop.DelegatingRecordReader.java Source code

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Here is the source code for com.ambiata.ivory.operation.hadoop.DelegatingRecordReader.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.ambiata.ivory.operation.hadoop;
/* WAS: package org.apache.hadoop.mapreduce.lib.input; */

import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
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 org.apache.hadoop.util.ReflectionUtils;

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

    /**
     * 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>) ReflectionUtils
                .newInstance(taggedInputSplit.getInputFormatClass(), context.getConfiguration());
        originalRR = inputFormat.createRecordReader(taggedInputSplit.getInputSplit(), context);
    }

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

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

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

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

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        originalRR.initialize(((TaggedInputSplit) split).getInputSplit(), context);
    }

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