com.ibm.jaql.io.hadoop.SelectSplitInputFormat.java Source code

Introduction

Here is the source code for com.ibm.jaql.io.hadoop.SelectSplitInputFormat.java

Source

/**
 * Copyright (C) IBM Corp. 2009.
 * 
 * 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.ibm.jaql.io.hadoop;

import java.io.IOException;
import java.lang.reflect.UndeclaredThrowableException;

import org.apache.hadoop.io.DataInputBuffer;
import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.JobConfigurable;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.util.ReflectionUtils;

/**
 * Reads a single split from an input format
 */
public class SelectSplitInputFormat<K, V> implements InputFormat<K, V>, JobConfigurable {
    public final static String BASE_NAME = SelectSplitInputFormat.class.getName();
    public final static String INPUT_FORMAT = BASE_NAME + ".input.format";
    public final static String SPLIT_CLASS = BASE_NAME + ".split.class";
    public final static String SPLIT = BASE_NAME + ".split.data";
    public final static String STATE = BASE_NAME + ".state";

    protected InputFormat<K, V> iFormat;
    protected InputSplit split;

    @Override
    public RecordReader<K, V> getRecordReader(InputSplit split, JobConf conf, Reporter reporter)
            throws IOException {
        return iFormat.getRecordReader(split, conf, reporter);
    }

    @Override
    public InputSplit[] getSplits(JobConf conf, int numSplits) throws IOException {
        return new InputSplit[] { split };
    }

    @Override
    public void configure(JobConf conf) {
        Class<? extends InputFormat> inputFormatCls = conf.getClass(INPUT_FORMAT, null, InputFormat.class);
        iFormat = ReflectionUtils.newInstance(inputFormatCls, conf);
        Class<? extends InputSplit> splitCls = conf.getClass(SPLIT_CLASS, null, InputSplit.class);
        split = ReflectionUtils.newInstance(splitCls, conf);
        byte[] bytes = ConfUtil.readBinary(conf, SPLIT);
        DataInputBuffer buffer = new DataInputBuffer();
        buffer.reset(bytes, bytes.length);
        try {
            split.readFields(buffer);
        } catch (IOException e) {
            throw new UndeclaredThrowableException(e);
        }
    }
}