org.apache.storm.daemon

Class GrouperFactory.FieldsGrouper

java.lang.Object

org.apache.storm.daemon.GrouperFactory.FieldsGrouper

All Implemented Interfaces:

Serializable, CustomStreamGrouping

Enclosing class:

GrouperFactory

public static class GrouperFactory.FieldsGrouper
extends Object
implements CustomStreamGrouping

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
FieldsGrouper(Fields outFields, Grouping thriftGrouping)

Method Summary

Modifier and Type	Method and Description
List<Integer>	chooseTasks(int taskId, List<Object> values) This function implements a custom stream grouping.
void	prepare(WorkerTopologyContext context, GlobalStreamId stream, List<Integer> targetTasks) Tells the stream grouping at runtime the tasks in the target bolt.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FieldsGrouper

public FieldsGrouper(Fields outFields,
                     Grouping thriftGrouping)

Method Detail

prepare

public void prepare(WorkerTopologyContext context,
                    GlobalStreamId stream,
                    List<Integer> targetTasks)

Description copied from interface: CustomStreamGrouping

Tells the stream grouping at runtime the tasks in the target bolt. This information should be used in chooseTasks to determine the target tasks.

It also tells the grouping the metadata on the stream this grouping will be used on.

Specified by:

prepare in interface CustomStreamGrouping

chooseTasks

public List<Integer> chooseTasks(int taskId,
                                 List<Object> values)

Description copied from interface: CustomStreamGrouping

This function implements a custom stream grouping. It takes in as input the number of tasks in the target bolt in prepare and returns the tasks to send the tuples to.

Specified by:

chooseTasks in interface CustomStreamGrouping

values - the values to group on