Package org.apache.storm.jdbc.spout

Class UserSpout

java.lang.Object
org.apache.storm.jdbc.spout.UserSpout
All Implemented Interfaces:
Serializable, ISpout, IComponent, IRichSpout
public class UserSpout extends Object implements IRichSpout
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final List<Values>
    rows
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    UserSpout()
     
    UserSpout(boolean isDistributed)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    ack(Object msgId)
    Storm has determined that the tuple emitted by this spout with the msgId identifier has been fully processed.
    void
    activate()
    Called when a spout has been activated out of a deactivated mode. nextTuple will be called on this spout soon.
    void
    close()
    Called when an ISpout is going to be shutdown.
    void
    deactivate()
    Called when a spout has been deactivated. nextTuple will not be called while a spout is deactivated.
    void
    declareOutputFields(OutputFieldsDeclarer declarer)
    Declare the output schema for all the streams of this topology.
    void
    fail(Object msgId)
    The tuple emitted by this spout with the msgId identifier has failed to be fully processed.
    Map<String,Object>
    getComponentConfiguration()
    Declare configuration specific to this component.
    boolean
    isDistributed()
     
    void
    nextTuple()
    When this method is called, Storm is requesting that the Spout emit tuples to the output collector.
    void
    open(Map<String,Object> conf, TopologyContext context, SpoutOutputCollector collector)
    Called when a task for this component is initialized within a worker on the cluster.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

  • Constructor Details

    • UserSpout

      public UserSpout()

    • UserSpout

      public UserSpout(boolean isDistributed)

  • Method Details

    • isDistributed

      public boolean isDistributed()

    • open

      public void open(Map<String,Object> conf, TopologyContext context, SpoutOutputCollector collector)
      Description copied from interface: ISpout
      Called when a task for this component is initialized within a worker on the cluster. It provides the spout with the environment in which the spout executes.

      This includes the:

      Specified by:
      open in interface ISpout
      Parameters:
      conf - The Storm configuration for this spout. This is the configuration provided to the topology merged in with cluster configuration on this machine.
      context - 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.
      collector - The collector is used to emit tuples from this spout. Tuples can be emitted at any time, including the open and close methods. The collector is thread-safe and should be saved as an instance variable of this spout object.

    • close

      public void close()
      Description copied from interface: ISpout
      Called when an ISpout is going to be shutdown. There is no guarentee that close will be called, because the supervisor kill -9's worker processes on the cluster.

      The one context where close is guaranteed to be called is a topology is killed when running Storm in local mode.

      Specified by:
      close in interface ISpout

    • nextTuple

      public void nextTuple()
      Description copied from interface: ISpout
      When this method is called, Storm is requesting that the Spout emit tuples to the output collector. This method should be non-blocking, so if the Spout has no tuples to emit, this method should return. nextTuple, ack, and fail are all called in a tight loop in a single thread in the spout task. When there are no tuples to emit, it is courteous to have nextTuple sleep for a short amount of time (like a single millisecond) so as not to waste too much CPU.
      Specified by:
      nextTuple in interface ISpout

    • ack

      public void ack(Object msgId)
      Description copied from interface: ISpout
      Storm has determined that the tuple emitted by this spout with the msgId identifier has been fully processed. Typically, an implementation of this method will take that message off the queue and prevent it from being replayed.
      Specified by:
      ack in interface ISpout

    • fail

      public void fail(Object msgId)
      Description copied from interface: ISpout
      The tuple emitted by this spout with the msgId identifier has failed to be fully processed. Typically, an implementation of this method will put that message back on the queue to be replayed at a later time.
      Specified by:
      fail in interface ISpout

    • declareOutputFields

      public void declareOutputFields(OutputFieldsDeclarer declarer)
      Description copied from interface: IComponent
      Declare the output schema for all the streams of this topology.
      Specified by:
      declareOutputFields in interface IComponent
      Parameters:
      declarer - this is used to declare output stream ids, output fields, and whether or not each output stream is a direct stream

    • activate

      public void activate()
      Description copied from interface: ISpout
      Called when a spout has been activated out of a deactivated mode. nextTuple will be called on this spout soon. A spout can become activated after having been deactivated when the topology is manipulated using the `storm` client.
      Specified by:
      activate in interface ISpout

    • deactivate

      public void deactivate()
      Description copied from interface: ISpout
      Called when a spout has been deactivated. nextTuple will not be called while a spout is deactivated. The spout may or may not be reactivated in the future.
      Specified by:
      deactivate in interface ISpout

    • getComponentConfiguration

      public Map<String,Object> getComponentConfiguration()
      Description copied from interface: IComponent
      Declare configuration specific to this component. Only a subset of the "topology.*" configs can be overridden. The component configuration can be further overridden when constructing the topology using TopologyBuilder
      Specified by:
      getComponentConfiguration in interface IComponent