org.apache.storm.mongodb.bolt

Class MongoLookupBolt

java.lang.Object

org.apache.storm.topology.base.BaseComponent

org.apache.storm.topology.base.BaseRichBolt

org.apache.storm.mongodb.bolt.AbstractMongoBolt

org.apache.storm.mongodb.bolt.MongoLookupBolt

All Implemented Interfaces:

Serializable, IBolt, IComponent, IRichBolt

public class MongoLookupBolt
extends AbstractMongoBolt

Basic bolt for querying from MongoDB. Note: Each MongoLookupBolt defined in a topology is tied to a specific collection.

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.storm.mongodb.bolt.AbstractMongoBolt

collector, mongoClient

Constructor Summary

Constructors

Constructor and Description
MongoLookupBolt(String url, String collectionName, QueryFilterCreator queryCreator, MongoLookupMapper mapper) MongoLookupBolt Constructor.

Method Summary

Modifier and Type	Method and Description
void	declareOutputFields(OutputFieldsDeclarer declarer) Declare the output schema for all the streams of this topology.
void	execute(Tuple tuple) Process a single tuple of input.

Methods inherited from class org.apache.storm.mongodb.bolt.AbstractMongoBolt

cleanup, prepare

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

Constructor Detail

MongoLookupBolt

public MongoLookupBolt(String url,
                       String collectionName,
                       QueryFilterCreator queryCreator,
                       MongoLookupMapper mapper)

MongoLookupBolt Constructor.

Parameters:

url - The MongoDB server url

collectionName - The collection where reading/writing data

queryCreator - QueryFilterCreator

mapper - MongoMapper converting tuple to an MongoDB document

Method Detail

execute

public void execute(Tuple tuple)

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:

tuple - The input tuple to be processed.

declareOutputFields

public void declareOutputFields(OutputFieldsDeclarer declarer)

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