com.alimama.quanjingmonitor.kmeans.KMeansClusterCombiner.java Source code

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Here is the source code for com.alimama.quanjingmonitor.kmeans.KMeansClusterCombiner.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.alimama.quanjingmonitor.kmeans;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.PriorityQueue;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

public class KMeansClusterCombiner extends Reducer<Text, Text, Text, Text> {

    private final Collection<Cluster> clusters = new ArrayList<Cluster>();

    private Map<String, Cluster> clusterMap;
    int rep = 2;

    private void setClusterMap(Collection<Cluster> clusters) {
        clusterMap = new HashMap<String, Cluster>();
        for (Cluster cluster : clusters) {
            clusterMap.put(String.valueOf(cluster.getId()), cluster);
        }
        clusters.clear();
    }

    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
        super.setup(context);
        this.clusters.clear();

        Configuration conf = context.getConfiguration();
        this.rep = conf.getInt(KMeansDriver.CLUSTER_CONVERGENCE_ABTEST_REP, 2);

        try {

            String clusterPath = conf.get(KMeansDriver.CLUSTER_PATH_KEY);
            if (clusterPath != null && clusterPath.length() > 0) {
                KmeansPublic.configureWithClusterInfo(conf, new Path(clusterPath), clusters);
                if (clusters.isEmpty()) {
                    throw new IllegalStateException("No clusters found. Check your -c path.");
                }
                this.setClusterMap(clusters);
            }
        } catch (Throwable e) {
            throw new IllegalStateException(e);
        }
    }

    Comparator<Text> cmp = new Comparator<Text>() {

        @Override
        public int compare(Text o1, Text o2) {
            String[] cols1 = o1.toString().split("@abtest@");
            String[] cols2 = o2.toString().split("@abtest@");

            double t1 = Double.parseDouble(cols1[0]);
            double t2 = Double.parseDouble(cols2[0]);
            return t1 == t2 ? 0 : t1 > t2 ? 1 : -1;

        }
    };

    @Override
    protected void reduce(Text key, Iterable<Text> values, Context context)
            throws IOException, InterruptedException {
        Cluster clu = clusterMap.get(key.toString());
        int limit = 1;
        if (clu != null) {
            limit = Math.min(clu.getNumselect() * this.rep * 10, 50000);

        }
        if (limit < 1000) {
            limit = 1000;
        }

        PriorityQueue<Text> res = new PriorityQueue<Text>(limit, Collections.reverseOrder(cmp));
        for (Text value : values) {

            if (res.size() < limit) {
                res.add(new Text(value.toString()));
            } else if (cmp.compare(res.peek(), new Text(value.toString())) > 0) {
                res.add(new Text(value.toString()));
                res.poll();
            }

        }
        for (Text s : res) {
            context.write(key, s);

        }
    }

}