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

Introduction

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

Prototype

public Class<? extends Reducer<?, ?, ?, ?>> getCombinerClass() throws ClassNotFoundException;

Source Link

Document

Get the combiner class for the job.

Usage

From source file:edu.uci.ics.hyracks.dataflow.hadoop.HadoopReducerOperatorDescriptor.java

License:Apache License

private Object createReducer() throws Exception {
    if (reducerClass != null) {
        return ReflectionUtils.newInstance(reducerClass, getJobConf());
    } else {/*  w  w  w.  j  a  v a2 s  .  c  o m*/
        Object reducer;
        if (!useAsCombiner) {
            if (getJobConf().getUseNewReducer()) {
                JobContext jobContext = new ContextFactory().createJobContext(getJobConf());
                reducerClass = (Class<? extends org.apache.hadoop.mapreduce.Reducer<?, ?, ?, ?>>) jobContext
                        .getReducerClass();
            } else {
                reducerClass = (Class<? extends Reducer>) getJobConf().getReducerClass();
            }
        } else {
            if (getJobConf().getUseNewReducer()) {
                JobContext jobContext = new ContextFactory().createJobContext(getJobConf());
                reducerClass = (Class<? extends org.apache.hadoop.mapreduce.Reducer<?, ?, ?, ?>>) jobContext
                        .getCombinerClass();
            } else {
                reducerClass = (Class<? extends Reducer>) getJobConf().getCombinerClass();
            }
        }
        reducer = getHadoopClassFactory().createReducer(reducerClass.getName(), getJobConf());
        return reducer;
    }
}

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