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

    All Methods Instance Methods Concrete Methods
    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

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