Class StreamletOperator<R,​T>

    • Constructor Detail

      • StreamletOperator

        public StreamletOperator()
    • Method Detail

      • prepare

        public void prepare​(Map<String,​Object> map,
                            TopologyContext topologyContext,
                            OutputCollector outputCollector)
        Description copied from interface: IBolt
        Called when a task for this component is initialized within a worker on the cluster. It provides the bolt with the environment in which the bolt executes.

        This includes the:

        Specified by:
        prepare in interface IBolt
        Parameters:
        map - The Heron configuration for this bolt. This is the configuration provided to the topology merged in with cluster configuration on this machine.
        topologyContext - This object can be used to get information about this task's place within the topology, including the task id and component id of this task, input and output information, etc.
        outputCollector - The collector is used to emit tuples from this bolt. Tuples can be emitted at any time, including the prepare and cleanup methods. The collector is thread-safe and should be saved as an instance variable of this bolt object.
      • declareOutputFields

        public void declareOutputFields​(OutputFieldsDeclarer outputFieldsDeclarer)
        The operators implementing streamlet functionality have some properties. 1. They all output only one stream 2. They should be able to consume each other's output This imply that the output stream should be named same for all of them.
        Specified by:
        declareOutputFields in interface IComponent
        Parameters:
        outputFieldsDeclarer - this is used to declare output stream ids, output fields, and whether or not each output stream is a direct stream