com.mongodb.hadoop.input.DelegatingInputFormat.java Source code

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Here is the source code for com.mongodb.hadoop.input.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.mongodb.hadoop.input;

import com.mongodb.hadoop.MongoInputFormat;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.mapreduce.lib.input.DelegatingRecordReader;
import org.apache.hadoop.mapreduce.lib.input.TaggedInputSplitGenerator;
import org.apache.hadoop.util.ReflectionUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

/**
 * An {@link InputFormat} that delegates behavior of paths to multiple other
 * InputFormats.
 * 
 * @see org.apache.hadoop.mapreduce.lib.input.MultipleInputs#addInputPath(Job, Path, Class, Class)
 */
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 = MongoMultipleInputs.getInputFormatMap(job);
        Map<Path, Class<? extends Mapper>> mapperMap = MongoMultipleInputs.getMapperTypeMap(job);
        //     Map<Class<? extends InputFormat>, List<Path>> formatPaths   = new HashMap<Class<? extends InputFormat>, List<Path>>();

        for (Entry<Path, InputFormat> entry : formatMap.entrySet()) {
            InputFormat formatClass = (InputFormat) ReflectionUtils.newInstance(entry.getValue().getClass(), conf);
            Class<? extends Mapper> mapperClass;
            mapperClass = mapperMap.get(entry.getKey());
            try {
                List<InputSplit> pathSplits = ((MongoInputFormat) formatClass).getSplits(jobCopy, entry.getKey());
                for (InputSplit pathSplit : pathSplits) {
                    splits.add(TaggedInputSplitGenerator.getTaggedInputSplit(pathSplit, conf,
                            formatClass.getClass(), mapperClass));
                }
            } catch (ClassCastException e) {
                List<InputSplit> pathSplits = formatClass.getSplits(jobCopy);
                for (InputSplit pathSplit : pathSplits) {
                    splits.add(TaggedInputSplitGenerator.getTaggedInputSplit(pathSplit, conf,
                            formatClass.getClass(), mapperClass));
                }
            }
        }
        return splits;
    }

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

    private static final Log log = LogFactory.getLog(DelegatingInputFormat.class);
}