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

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Here is the source code for com.ambiata.ivory.operation.hadoop.DelegatingInputFormat.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 java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; /* WAS not required in old package */
import org.apache.hadoop.util.ReflectionUtils;

/**
 * An {@link InputFormat} that delegates behavior of paths to multiple other
 * InputFormats.
 *
 * @see MultipleInputs#addInputPath(Job, Path, Class, Class)
 */
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class DelegatingInputFormat<K, V> extends InputFormat<K, V> {

    @SuppressWarnings("unchecked")
    public List<InputSplit> getSplits(JobContext job) throws IOException, InterruptedException {
        Configuration conf = job.getConfiguration();
        Job jobCopy = new Job(conf);
        List<InputSplit> splits = new ArrayList<InputSplit>();
        Map<Path, InputFormat> formatMap = MultipleInputs.getInputFormatMap(job);
        Map<Path, Class<? extends Mapper>> mapperMap = MultipleInputs.getMapperTypeMap(job);
        Map<Class<? extends InputFormat>, List<Path>> formatPaths = new HashMap<Class<? extends InputFormat>, List<Path>>();

        // First, build a map of InputFormats to Paths
        for (Entry<Path, InputFormat> entry : formatMap.entrySet()) {
            if (!formatPaths.containsKey(entry.getValue().getClass())) {
                formatPaths.put(entry.getValue().getClass(), new LinkedList<Path>());
            }

            formatPaths.get(entry.getValue().getClass()).add(entry.getKey());
        }

        for (Entry<Class<? extends InputFormat>, List<Path>> formatEntry : formatPaths.entrySet()) {
            Class<? extends InputFormat> formatClass = formatEntry.getKey();
            InputFormat format = (InputFormat) ReflectionUtils.newInstance(formatClass, conf);
            List<Path> paths = formatEntry.getValue();

            Map<Class<? extends Mapper>, List<Path>> mapperPaths = new HashMap<Class<? extends Mapper>, List<Path>>();

            // Now, for each set of paths that have a common InputFormat, build
            // a map of Mappers to the paths they're used for
            for (Path path : paths) {
                Class<? extends Mapper> mapperClass = mapperMap.get(path);
                if (!mapperPaths.containsKey(mapperClass)) {
                    mapperPaths.put(mapperClass, new LinkedList<Path>());
                }

                mapperPaths.get(mapperClass).add(path);
            }

            // Now each set of paths that has a common InputFormat and Mapper can
            // be added to the same job, and split together.
            for (Entry<Class<? extends Mapper>, List<Path>> mapEntry : mapperPaths.entrySet()) {
                paths = mapEntry.getValue();
                Class<? extends Mapper> mapperClass = mapEntry.getKey();

                if (mapperClass == null) {
                    try {
                        mapperClass = job.getMapperClass();
                    } catch (ClassNotFoundException e) {
                        throw new IOException("Mapper class is not found", e);
                    }
                }

                FileInputFormat.setInputPaths(jobCopy, paths.toArray(new Path[paths.size()]));

                // Get splits for each input path and tag with InputFormat
                // and Mapper types by wrapping in a TaggedInputSplit.
                List<InputSplit> pathSplits = format.getSplits(jobCopy);
                for (InputSplit pathSplit : pathSplits) {
                    splits.add(new TaggedInputSplit(pathSplit, conf, format.getClass(), mapperClass));
                }
            }
        }

        return splits;
    }

    @Override
    public RecordReader<K, V> createRecordReader(InputSplit split, TaskAttemptContext context)
            throws IOException, InterruptedException {
        return new DelegatingRecordReader<K, V>(split, context);
    }
}