public class HdfsStringSpout extends BaseRichSpout
Note1: The hadoop cluster config should be provided through the classpath Note2: The number of parallelisms for this spout should be equal to the number of files/paths to read.
Constructor and Description |
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HdfsStringSpout(java.lang.String path) |
HdfsStringSpout(java.lang.String[] paths) |
Modifier and Type | Method and Description |
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void |
declareOutputFields(OutputFieldsDeclarer declarer)
Declare the output schema for all the streams of this topology.
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void |
nextTuple()
When this method is called, Heron is requesting that the Spout emit tuples to the
output collector.
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void |
open(java.util.Map<java.lang.String,java.lang.Object> stormConf,
TopologyContext context,
SpoutOutputCollector newCollector)
Called when a task for this component is initialized within a worker on the cluster.
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ack, activate, close, deactivate, fail
getComponentConfiguration
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
getComponentConfiguration
public HdfsStringSpout(java.lang.String path)
public HdfsStringSpout(java.lang.String[] paths)
public void declareOutputFields(OutputFieldsDeclarer declarer)
IComponent
declarer
- this is used to declare output stream ids, output fields, and whether or not each output stream is a direct streampublic void open(java.util.Map<java.lang.String,java.lang.Object> stormConf, TopologyContext context, SpoutOutputCollector newCollector)
ISpout
This includes the:
stormConf
- The Heron 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.newCollector
- 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.public void nextTuple()
ISpout