Storm的常见模式---求TOPN

参考了storm-starter和很多网上的例子。
总共需要三个bolt:

//bolt1,负责实时的计算某个但是的统计量;负责清空最旧的数据。
package com.cucc.roam.storm.bolt;
import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;
import backtype.storm.utils.Utils;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.log4j.Logger;

public class RollingCountObjects extends BaseRichBolt {
    public static Logger LOG = Logger.getLogger(RollingCountObjects.class);
    private HashMaplong[]> _objectCounts = new HashMaplong[]>();
    private int _numBuckets;//60
    private transient Thread cleaner;
    private OutputCollector _collector;
    private int _trackMinutes;//10

    public RollingCountObjects(int numBuckets, int trackMinutes) {
        _numBuckets = numBuckets;
        _trackMinutes = trackMinutes;
    }

    public long totalObjects (Object obj) {
        long[] curr = _objectCounts.get(obj);
        long total = 0;
        for (long l: curr) {
            total+=l;
        }
        return total;
    }

    public int currentBucket (int buckets) {
        return (currentSecond()  / secondsPerBucket(buckets)) % buckets;
    }

    public int currentSecond() {//系统时间,秒
        return (int) (System.currentTimeMillis() / 1000);
    }

    public int secondsPerBucket(int buckets) {
        return (_trackMinutes * 60 / buckets);//每个桶多少秒,

    }

    public long millisPerBucket(int buckets) {
        return (long) secondsPerBucket(buckets) * 1000;
    }

    public void prepare(Map stormConf, TopologyContext context, OutputCollector collector) {
        _collector = collector;
        cleaner = new Thread(new Runnable() {
            public void run() {
                Integer lastBucket = currentBucket(_numBuckets);
                StringBuffer sb = new StringBuffer();

                while(true) {
                  int currBucket = currentBucket(_numBuckets);

                  sb.setLength(0);
                  sb.append("\n##########\nbegin,线程while循环： 当前的桶为：" + currBucket);


                  if(currBucket!=lastBucket) {
                      sb.append("\n线程while循环:之前的桶数为：" + lastBucket);

                      int bucketToWipe = (currBucket + 1) % _numBuckets;
                      sb.append("\n线程while循环:要擦除掉的桶为：" + bucketToWipe);

                      synchronized(_objectCounts) {
                          Set objs = new HashSet(_objectCounts.keySet());
                          for (Object obj: objs) {
                            long[] counts = _objectCounts.get(obj);
                            long currBucketVal = counts[bucketToWipe];
                            sb.append("\n线程while循环:擦除掉的值为:" + currBucketVal+",擦除的对象为"+obj);

                            sb.append("\n擦出前数组:");//LOG.info
                            for (long number : counts) {
                                sb.append(number + ":");
                            }

                            counts[bucketToWipe] = 0;
                            sb.append("\n擦出后数组:");
                            for (long number : counts) {
                                sb.append(number + ":");
                            }

                            long total = totalObjects(obj);
                            if(currBucketVal!=0) {
                                sb.append("\n线程while循环:擦除掉的值为不为0：那就发射数据：obj total"
                                            + obj + ":" + total);
                                _collector.emit(new Values(obj, total));
                            }
                            if(total==0) {
                                sb.append("\n线程while循环: 总数为0以后,将obj对象删除,obj="+obj);
                                _objectCounts.remove(obj);
                            }
                          }
                      }
                      lastBucket = currBucket;
                  }
                  long delta = millisPerBucket(_numBuckets) - (System.currentTimeMillis() % millisPerBucket(_numBuckets));
                  Utils.sleep(delta);
                  sb.append("\nsleep="+delta+"毫秒.end#########\n");
                  LOG.info(sb.toString());
                }
            }
        });
        cleaner.start();
    }

    public void execute(Tuple tuple) {
        StringBuffer sb = new StringBuffer();
        sb.setLength(0);
        Object obj = tuple.getValue(0);
        int bucket = currentBucket(_numBuckets);
        sb.append("\n=======\nexecute方法:当前值:"+obj+"当前桶：bucket： " + bucket);
        synchronized(_objectCounts) {
            long[] curr = _objectCounts.get(obj);
            if(curr==null) {
                curr = new long[_numBuckets];
                _objectCounts.put(obj, curr);
                sb.append("\n新建,_objectCounts["+_objectCounts.toString()+"]");
            }
            curr[bucket]++;
            sb.append("\nexecute方法：接受到的merchandiseIDS:" + obj.toString() + ",long数组：\n");

            for (long number : curr) {
                sb.append(number + ":");
            }

            sb.append("\nexecute方法:发射的数据： " + obj + ":" + totalObjects(obj)+"\n========");

            _collector.emit(new Values(obj, totalObjects(obj)));
            _collector.ack(tuple);
            LOG.info(sb.toString());
        }
    }
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("obj", "count"));
    }
}

bolt2维护一个topn的数据，假如bolt2的并发度为3那么总共有三组topN的数据

package com.cucc.roam.storm.bolt;

import backtype.storm.task.TopologyContext;
import backtype.storm.topology.BasicOutputCollector;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseBasicBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;


public class RankObjects extends BaseBasicBolt {
    public static Logger LOG = Logger.getLogger(RankObjects.class);

    List _rankings = new ArrayList();

    int _count;
    Long _lastTime = null;

    public RankObjects(int n) {
        _count = n;
    }

    private int _compare(List one, List two) {
        long valueOne = (Long) one.get(1);
        long valueTwo = (Long) two.get(1);
        long delta = valueTwo - valueOne;
        if(delta > 0) {
            return 1;
        } else if (delta < 0) {
            return -1;
        } else {
            return 0;
        }
    }

    private Integer _find(Object tag) {
        for(int i = 0; i < _rankings.size(); ++i) {
            Object cur = _rankings.get(i).get(0);
            if (cur.equals(tag)) {
                return i;
            }
        }
        return null;
    }

    public void execute(Tuple tuple, BasicOutputCollector collector) {
        StringBuffer sb = new StringBuffer();
        Object tag = tuple.getValue(0);
        sb.append("\n~~~~~~~~~\nrank,tag="+tag+",_rankings["+_rankings.toString()+"].");
        Integer existingIndex = _find(tag);
        if (null != existingIndex) {
            sb.append("\nrank,set["+tuple.getValues()+"]..");
            _rankings.set(existingIndex, tuple.getValues());
        } else {
            sb.append("\nrank,add["+tuple.getValues()+"]..");
            _rankings.add(tuple.getValues());
        }
        Collections.sort(_rankings, new Comparator() {
            public int compare(List o1, List o2) {
                return _compare(o1, o2);
            }
        });
        if (_rankings.size() > _count) {
            _rankings.remove(_count);
            sb.append("\nremove后,_rankings["+_rankings.toString()+"].");
        }
        long currentTime = System.currentTimeMillis();
        if(_lastTime==null || currentTime >= _lastTime + 2000) {
            sb.append("\nrank,emit["+_rankings+"]...");
            collector.emit(new Values(new ArrayList(_rankings)));
            _lastTime = currentTime;
        }
        sb.append("\n~~~~~~~~~~~\n");
        LOG.info(sb.toString());
    }

    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("list"));
    }
}

bolt3的作用是合并

package com.cucc.roam.storm.bolt;

import org.apache.log4j.Logger;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.BasicOutputCollector;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseBasicBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;

public class MergeObjects extends BaseBasicBolt {
    public static Logger LOG = Logger.getLogger(MergeObjects.class);

    private List _rankings = new ArrayList();
    int _count = 10;
    Long _lastTime;

    public MergeObjects(int n) {
        _count = n;
    }

    private int _compare(List one, List two) {
        long valueOne = (Long) one.get(1);
        long valueTwo = (Long) two.get(1);
        long delta = valueTwo - valueOne;
        if(delta > 0) {
            return 1;
        } else if (delta < 0) {
            return -1;
        } else {
            return 0;
        }
    }

    private Integer _find(Object tag) {
        for(int i = 0; i < _rankings.size(); ++i) {
            Object cur = _rankings.get(i).get(0);
            if (cur.equals(tag)) {
                return i;
            }
        }
        return null;
    }

    public void execute(Tuple tuple, BasicOutputCollector collector) {
        StringBuffer sb = new StringBuffer();
        List merging = (List) tuple.getValue(0);
        sb.append("\n$$$$$$$$$$$$$\nmerge,get,merging["+merging.toString()+"].");
        sb.append("\n 开始_rankings["+_rankings.toString()+"]");
        for(List pair : merging) {
            Integer existingIndex = _find(pair.get(0));
            if (null != existingIndex) {
                _rankings.set(existingIndex, pair);
                sb.append("");
            } else {
                _rankings.add(pair);
                sb.append("");
            }

            Collections.sort(_rankings, new Comparator() {
                public int compare(List o1, List o2) {
                    return _compare(o1, o2);
                }
            });

            if (_rankings.size() > _count) {
                _rankings.subList(_count, _rankings.size()).clear();
            }
        }
        sb.append("\n结束_rankings["+_rankings.toString()+"]");

        long currentTime = System.currentTimeMillis();
        if(_lastTime==null || currentTime >= _lastTime + 2000) {
            collector.emit(new Values(new ArrayList(_rankings)));
            LOG.info("\n最后的实时结果Rankings: " + _rankings);
            _lastTime = currentTime;
        }
        sb.append("\n$$$$$$$$$$$$$\n");
        LOG.info(sb.toString());
    }

    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("list"));
    }
}

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转载：http://my.oschina.net/infiniteSpace/blog/309784