Package org.apache.storm.redis.topology
Class WhitelistWordCount.PrintWordTotalCountBolt
java.lang.Object
org.apache.storm.topology.base.BaseComponent
org.apache.storm.topology.base.BaseRichBolt
org.apache.storm.redis.topology.WhitelistWordCount.PrintWordTotalCountBolt
- All Implemented Interfaces:
Serializable
,IBolt
,IComponent
,IRichBolt
- Enclosing class:
- WhitelistWordCount
- See Also:
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionvoid
declareOutputFields
(OutputFieldsDeclarer declarer) Declare the output schema for all the streams of this topology.void
Process a single tuple of input.void
prepare
(Map<String, Object> topoConf, TopologyContext context, OutputCollector collector) Called when a task for this component is initialized within a worker on the cluster.Methods inherited from class org.apache.storm.topology.base.BaseRichBolt
cleanup
Methods inherited from class org.apache.storm.topology.base.BaseComponent
getComponentConfiguration
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.apache.storm.topology.IComponent
getComponentConfiguration
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Constructor Details
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PrintWordTotalCountBolt
public PrintWordTotalCountBolt()
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Method Details
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prepare
public void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector collector) 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:
- Parameters:
topoConf
- The Storm configuration for this bolt. 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 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.
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execute
Description copied from interface:IBolt
Process a single tuple of input. The Tuple object contains metadata on it about which component/stream/task it came from. The values of the Tuple can be accessed using Tuple#getValue. The IBolt does not have to process the Tuple immediately. It is perfectly fine to hang onto a tuple and process it later (for instance, to do an aggregation or join).Tuples should be emitted using the OutputCollector provided through the prepare method. It is required that all input tuples are acked or failed at some point using the OutputCollector. Otherwise, Storm will be unable to determine when tuples coming off the spouts have been completed.
For the common case of acking an input tuple at the end of the execute method, see IBasicBolt which automates this.
- Parameters:
input
- The input tuple to be processed.
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declareOutputFields
Description copied from interface:IComponent
Declare the output schema for all the streams of this topology.- 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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