Example usage for org.apache.hadoop.mapreduce JobContext getMapOutputKeyClass

Introduction

In this page you can find the example usage for org.apache.hadoop.mapreduce JobContext getMapOutputKeyClass.

Prototype

public Class<?> getMapOutputKeyClass();

Source Link

Document

Get the key class for the map output data.

Usage

From source file:com.scaleoutsoftware.soss.hserver.hadoop.ReducerWrapperMapreduce.java

License:Apache License

public ReducerWrapperMapreduce(HServerInvocationParameters invocationParameters, int hadoopPartition, int appId,
        int region, boolean sort) throws IOException, ClassNotFoundException, InterruptedException {
    this.invocationParameters = invocationParameters;
    Configuration configuration = (Configuration) invocationParameters.getConfiguration();
    hadoopVersionSpecificCode = HadoopVersionSpecificCode.getInstance(invocationParameters.getHadoopVersion(),
            configuration);//  w w w  .  j  a v  a  2 s.c  om
    JobID jobID = (JobID) invocationParameters.getJobId();

    //Setup task ID info
    TaskAttemptID id = hadoopVersionSpecificCode.createTaskAttemptId(jobID, false, hadoopPartition);
    JobContext jobContext = hadoopVersionSpecificCode.createJobContext(new JobConf(configuration), jobID);
    taskContext = hadoopVersionSpecificCode.createTaskAttemptContext(configuration, id);

    reducer = (org.apache.hadoop.mapreduce.Reducer<INKEY, INVALUE, OUTKEY, OUTVALUE>) ReflectionUtils
            .newInstance(jobContext.getReducerClass(), configuration);

    OutputFormat outputFormat = ReflectionUtils.newInstance(jobContext.getOutputFormatClass(), configuration);

    recordWriter = (org.apache.hadoop.mapreduce.RecordWriter<OUTKEY, OUTVALUE>) outputFormat
            .getRecordWriter(taskContext);

    committer = outputFormat.getOutputCommitter(taskContext);
    committer.setupTask(taskContext);

    Class<INKEY> keyClass = (Class<INKEY>) jobContext.getMapOutputKeyClass();
    WritableSerializerDeserializer<INKEY> firstKeySerializer = new WritableSerializerDeserializer<INKEY>(
            keyClass, null);
    WritableSerializerDeserializer<INKEY> secondKeySerializer = new WritableSerializerDeserializer<INKEY>(
            keyClass, null);
    Class<INVALUE> valueClass = (Class<INVALUE>) jobContext.getMapOutputValueClass();
    WritableSerializerDeserializer<INVALUE> valueSerializer = new WritableSerializerDeserializer<INVALUE>(
            valueClass, null);

    DataGridReaderParameters<INKEY, INVALUE> params = new DataGridReaderParameters<INKEY, INVALUE>(region,
            appId, HServerParameters.getSetting(REDUCE_USEMEMORYMAPPEDFILES, configuration) > 0,
            firstKeySerializer, valueSerializer, invocationParameters.getSerializationMode(),
            secondKeySerializer, keyClass, valueClass, sort,
            HServerParameters.getSetting(REDUCE_CHUNKSTOREADAHEAD, configuration),
            1024 * HServerParameters.getSetting(REDUCE_INPUTCHUNKSIZE_KB, configuration),
            HServerParameters.getSetting(REDUCE_CHUNKREADTIMEOUT, configuration));
    DataGridChunkedCollectionReader<INKEY, INVALUE> transport = DataGridChunkedCollectionReader
            .getGridReader(params);

    context = hadoopVersionSpecificCode.getReducerContext(configuration, id, committer, recordWriter, transport,
            null);

}

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