Package org.apache.storm.jdbc.spout
Class UserSpout
java.lang.Object
org.apache.storm.jdbc.spout.UserSpout
- All Implemented Interfaces:
Serializable,ISpout,IComponent,IRichSpout
- See Also:
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoidStorm has determined that the tuple emitted by this spout with the msgId identifier has been fully processed.voidactivate()Called when a spout has been activated out of a deactivated mode. nextTuple will be called on this spout soon.voidclose()Called when an ISpout is going to be shutdown.voidCalled when a spout has been deactivated. nextTuple will not be called while a spout is deactivated.voiddeclareOutputFields(OutputFieldsDeclarer declarer) Declare the output schema for all the streams of this topology.voidThe tuple emitted by this spout with the msgId identifier has failed to be fully processed.Declare configuration specific to this component.booleanvoidWhen this method is called, Storm is requesting that the Spout emit tuples to the output collector.voidopen(Map<String, Object> conf, TopologyContext context, SpoutOutputCollector collector) Called when a task for this component is initialized within a worker on the cluster.
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Field Details
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rows
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Constructor Details
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UserSpout
public UserSpout() -
UserSpout
public UserSpout(boolean isDistributed)
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Method Details
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isDistributed
public boolean isDistributed() -
open
Description copied from interface:ISpoutCalled 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:
openin interfaceISpout- 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.
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close
public void close()Description copied from interface:ISpoutCalled 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.
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nextTuple
public void nextTuple()Description copied from interface:ISpoutWhen 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. -
ack
Description copied from interface:ISpoutStorm 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. -
fail
Description copied from interface:ISpoutThe 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. -
declareOutputFields
Description copied from interface:IComponentDeclare the output schema for all the streams of this topology.- Specified by:
declareOutputFieldsin interfaceIComponent- Parameters:
declarer- this is used to declare output stream ids, output fields, and whether or not each output stream is a direct stream
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activate
public void activate()Description copied from interface:ISpoutCalled 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. -
deactivate
public void deactivate()Description copied from interface:ISpoutCalled 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:
deactivatein interfaceISpout
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getComponentConfiguration
Description copied from interface:IComponentDeclare 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 usingTopologyBuilder- Specified by:
getComponentConfigurationin interfaceIComponent
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