co.cask.cdap.internal.app.runtime.batch.dataset.input.MultiInputFormat.java Source code

Introduction

Here is the source code for co.cask.cdap.internal.app.runtime.batch.dataset.input.MultiInputFormat.java

Source

/*
 * Copyright  2016 Cask Data, Inc.
 *
 * 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 co.cask.cdap.internal.app.runtime.batch.dataset.input;

import co.cask.cdap.common.conf.ConfigurationUtil;
import com.google.common.base.Preconditions;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapred.JobID;
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.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.util.ReflectionUtils;

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

/**
 * An {@link InputFormat} that delegates behavior of InputFormat to multiple other InputFormats.
 *
 * @see MultipleInputs#addInput(Job, String, String, Map, Class)
 *
 * @param <K> Type of key
 * @param <V> Type of value
 */
public class MultiInputFormat<K, V> extends InputFormat<K, V> {

    @SuppressWarnings("unchecked")
    public List<InputSplit> getSplits(JobContext job) throws IOException, InterruptedException {
        List<InputSplit> splits = new ArrayList<>();
        Map<String, MultipleInputs.MapperInput> mapperInputMap = MultipleInputs.getInputMap(job.getConfiguration());

        for (Map.Entry<String, MultipleInputs.MapperInput> mapperInputEntry : mapperInputMap.entrySet()) {
            String inputName = mapperInputEntry.getKey();
            MultipleInputs.MapperInput mapperInput = mapperInputEntry.getValue();
            String mapperClassName = mapperInput.getMapperClassName();
            Job jobCopy = new Job(job.getConfiguration());
            Configuration confCopy = jobCopy.getConfiguration();

            // set configuration specific for this input onto the jobCopy
            ConfigurationUtil.setAll(mapperInput.getInputFormatConfiguration(), confCopy);

            Class<?> inputFormatClass = confCopy.getClassByNameOrNull(mapperInput.getInputFormatClassName());
            Preconditions.checkNotNull(inputFormatClass, "Class could not be found: ",
                    mapperInput.getInputFormatClassName());

            InputFormat<K, V> inputFormat = (InputFormat) ReflectionUtils.newInstance(inputFormatClass, confCopy);
            //some input format need a jobId to getSplits
            jobCopy.setJobID(new JobID(inputName, inputName.hashCode()));

            // Get splits for each input path and tag with InputFormat
            // and Mapper types by wrapping in a MultiInputTaggedSplit.
            List<InputSplit> formatSplits = inputFormat.getSplits(jobCopy);
            for (InputSplit split : formatSplits) {
                splits.add(new MultiInputTaggedSplit(split, confCopy, inputName,
                        mapperInput.getInputFormatConfiguration(), inputFormat.getClass(), mapperClassName));
            }
        }
        return splits;
    }

    @Override
    public RecordReader<K, V> createRecordReader(InputSplit split, TaskAttemptContext context)
            throws IOException, InterruptedException {
        MultiInputTaggedSplit taggedInputSplit = (MultiInputTaggedSplit) split;
        ConfigurationUtil.setAll((taggedInputSplit).getInputConfigs(), context.getConfiguration());
        InputFormat<K, V> inputFormat = (InputFormat<K, V>) ReflectionUtils
                .newInstance(taggedInputSplit.getInputFormatClass(), context.getConfiguration());
        InputSplit inputSplit = taggedInputSplit.getInputSplit();
        // we can't simply compute the underlying RecordReader and return it, because we need to override its
        // initialize method in order to initialize the underlying RecordReader with the underlying InputSplit
        // Find the InputFormat and then the RecordReader from the MultiInputTaggedSplit.
        return new DelegatingRecordReader<>(inputFormat.createRecordReader(inputSplit, context));
    }
}