Examples of backtype.storm.task.IBolt

backtype.storm.task.IBolt

An IBolt represents a component that takes tuples as input and produces tuples as output. An IBolt can do everything from filtering to joining to functions to aggregations. It does not have to process a tuple immediately and may hold onto tuples to process later.

A bolt's lifecycle is as follows:

IBolt object created on client machine. The IBolt is serialized into the topology (using Java serialization) and submitted to the master machine of the cluster (Nimbus). Nimbus then launches workers which deserialize the object, call prepare on it, and then start processing tuples.

If you want to parameterize an IBolt, you should set the parameter's through its constructor and save the parameterization state as instance variables (which will then get serialized and shipped to every task executing this bolt across the cluster).

When defining bolts in Java, you should use the IRichBolt interface which adds necessary methods for using the Java TopologyBuilder API.

      fields.add("id");
  
      outputs.put(ACKER_ACK_STREAM_ID, Thrift.directOutputFields(fields));
      outputs.put(ACKER_FAIL_STREAM_ID, Thrift.directOutputFields(fields));
  
      IBolt ackerbolt= new Acker();
      Map<GlobalStreamId, Grouping> inputs=acker_inputs(ret);
      Bolt acker_bolt = Thrift.mkAckerBolt(inputs, ackerbolt, outputs, num_tasks);
      for (Entry<String, Bolt> e : ret.get_bolts().entrySet()) {
          Bolt bolt = e.getValue();
          ComponentCommon common = bolt.get_common();

    fields.add("id");


    outputs.put(ACKER_ACK_STREAM_ID, Thrift.directOutputFields(fields));
    outputs.put(ACKER_FAIL_STREAM_ID, Thrift.directOutputFields(fields));


    IBolt ackerbolt = new Acker();


    // generate inputs
    Map<GlobalStreamId, Grouping> inputs = acker_inputs(ret);


    // generate acker which will be stored in topology

Examples of backtype.storm.task.IBolt

Related Classes of backtype.storm.task.IBolt