com.tdunning.plume.local.lazy.MSCRReducer.java Source code

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Here is the source code for com.tdunning.plume.local.lazy.MSCRReducer.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.tdunning.plume.local.lazy;

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

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.output.MultipleOutputs;

import com.google.common.collect.Lists;
import com.tdunning.plume.DoFn;
import com.tdunning.plume.EmitFn;
import com.tdunning.plume.PCollection;
import com.tdunning.plume.PTable;
import com.tdunning.plume.Pair;
import com.tdunning.plume.local.lazy.MSCR.OutputChannel;
import com.tdunning.plume.local.lazy.MapRedExecutor.PlumeObject;
import com.tdunning.plume.local.lazy.op.ParallelDo;

/**
 * Reducer that is used to execute MSCR in MapReds
 */
public class MSCRReducer extends Reducer<PlumeObject, PlumeObject, NullWritable, NullWritable> {

    MultipleOutputs mos;
    MSCR mscr; // Current MSCR being executed

    protected void setup(Reducer<PlumeObject, PlumeObject, NullWritable, NullWritable>.Context context)
            throws IOException, InterruptedException {

        this.mos = new MultipleOutputs(context);
        this.mscr = MapRedExecutor.readMSCR(context.getConfiguration());
    }

    protected void cleanup(Reducer<PlumeObject, PlumeObject, NullWritable, NullWritable>.Context context)
            throws IOException, InterruptedException {

        mos.close();
    }

    @SuppressWarnings("unchecked")
    protected void reduce(final PlumeObject arg0, java.lang.Iterable<PlumeObject> values,
            Reducer<PlumeObject, PlumeObject, NullWritable, NullWritable>.Context arg2)
            throws IOException, InterruptedException {

        PCollection col = mscr.getChannelByNumber().get(arg0.sourceId);
        OutputChannel oC = mscr.getOutputChannels().get(col);
        if (oC.reducer != null) {
            // apply reducer
            ParallelDo pDo = oC.reducer;
            DoFn reducer = pDo.getFunction(); // TODO how to check / report this
            List<WritableComparable> vals = Lists.newArrayList();
            for (PlumeObject val : values) {
                vals.add(val.obj);
            }
            reducer.process(Pair.create(arg0.obj, vals), new EmitFn() {
                @Override
                public void emit(Object v) {
                    try {
                        if (v instanceof Pair) {
                            Pair p = (Pair) v;
                            mos.write(arg0.sourceId + "", p.getKey(), p.getValue());
                        } else {
                            mos.write(arg0.sourceId + "", NullWritable.get(), (WritableComparable) v);
                        }
                    } catch (Exception e) {
                        e.printStackTrace(); // TODO How to report this
                    }
                }
            });
        } else {
            // direct writing - write all key, value pairs
            for (PlumeObject val : values) {
                if (oC.output instanceof PTable) {
                    mos.write(arg0.sourceId + "", arg0.obj, val.obj);
                } else {
                    mos.write(arg0.sourceId + "", NullWritable.get(), val.obj);
                }
            }
        }
    }
}