com.zqh.giraph.standalone.SimpleAggregatorWriter.java Source code

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Here is the source code for com.zqh.giraph.standalone.SimpleAggregatorWriter.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.zqh.giraph.standalone;

import java.io.IOException;
import java.util.Map.Entry;
import org.apache.giraph.aggregators.AggregatorWriter;
import org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.Mapper.Context;
import org.apache.log4j.Logger;

/**
 * This is a simple example for an aggregator writer. After each superstep
 * the writer will persist the aggregator values to disk, by use of the
 * Writable interface. The file will be created on the current working
 * directory.
 */
public class SimpleAggregatorWriter extends DefaultImmutableClassesGiraphConfigurable implements AggregatorWriter {
    /** Name of the file we wrote to */
    private static String FILENAME;
    /** Saved output stream to write to */
    private FSDataOutputStream output;

    public static String getFilename() {
        return FILENAME;
    }

    @SuppressWarnings("rawtypes")
    @Override
    public void initialize(Context context, long applicationAttempt) throws IOException {
        setFilename(applicationAttempt);
        Path p = new Path(FILENAME);
        FileSystem fs = FileSystem.get(context.getConfiguration());
        output = fs.create(p, true);
    }

    /**
     * Set filename written to
     *
     * @param applicationAttempt app attempt
     */
    private static void setFilename(long applicationAttempt) {
        FILENAME = "aggregatedValues_" + applicationAttempt;
    }

    @Override
    public void writeAggregator(Iterable<Entry<String, Writable>> aggregatorMap, long superstep)
            throws IOException {
        for (Entry<String, Writable> entry : aggregatorMap) {
            entry.getValue().write(output);
            Logger.getLogger(this.getClass()).info(entry.getValue().toString());
            System.out.println(entry.getValue().toString());
        }
        output.flush();
    }

    @Override
    public void close() throws IOException {
        output.close();
    }
}