我正在尝试编写一个执行以下操作的拓扑：
>订阅一个twitter Feed(基于关键字)
>一个聚合螺栓,用于聚合收集中的一些tweets(例如N),并将它们发送给打印机螺栓
>一个简单的螺栓,将集合一次打印到控制台.
在现实中,我想对收藏进行一些更多的处理.
我在本地测试,看起来像是在工作.但是,我不知道我是否正确设置了螺栓上的分组,并且在部署在实际的风暴集群上时可以正常工作.如果有人可以帮助您查看此拓扑并提出任何错误,更改或改进,我将不胜感激.
谢谢.
这是我的拓扑结构.
builder.setSpout("spout",new TwitterFilterSpout("pittsburgh"));
builder.setBolt("sampleaggregate",new SampleAggregatorBolt())
.shuffleGrouping("spout");
builder.setBolt("printaggreator",new PrinterBolt()).shuffleGrouping("sampleaggregate");
聚合螺栓
public class SampleAggregatorBolt implements IRichBolt {
protected OutputCollector collector;
protected Tuple currentTuple;
protected Logger log;
/**
* Holds the messages in the bolt till you are ready to send them out
*/
protected List<Status> statusCache;
@Override
public void prepare(Map stormConf,TopologyContext context,OutputCollector collector) {
this.collector = collector;
log = Logger.getLogger(getClass().getName());
statusCache = new ArrayList<Status>();
}
@Override
public void execute(Tuple tuple) {
currentTuple = tuple;
Status currentStatus = null;
try {
currentStatus = (Status) tuple.getValue(0);
} catch (ClassCastException e) {
}
if (currentStatus != null) {
//add it to the status cache
statusCache.add(currentStatus);
collector.ack(tuple);
//check the size of the status cache and pass it to the next stage if you have enough messages to emit
if (statusCache.size() > 10) {
collector.emit(new Values(statusCache));
}
}
}
@Override
public void cleanup() {
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("tweets"));
}
@Override
public Map<String,Object> getComponentConfiguration() {
return null; //To change body of implemented methods use File | Settings | File Templates.
}
protected void setupNonSerializableAttributes() {
}
}
打印机螺栓
public class PrinterBolt extends BaseBasicBolt {
@Override
public void execute(Tuple tuple,BasicOutputCollector collector) {
System.out.println(tuple.size() + " " + tuple);
}
@Override
public void declareOutputFields(OutputFieldsDeclarer ofd) {
}
}
