cascading.operation

Interface AggregatorCall<C>

All Superinterfaces:

OperationCall<C>

All Known Implementing Classes:

ConcreteCall

public interface AggregatorCall<C>
extends OperationCall<C>

Interface AggregatorCall provides access to the current Aggregator invocation arguments.

This interface is generic, allowing the user to set a custom 'context' object when Aggregator.start(cascading.flow.FlowProcess, AggregatorCall) is called. The OperationCall.setContext(Object) and OperationCall.getContext() methods are inherited from OperationCall.

See Also:

Aggregator, OperationCall

Method Summary

Methods

Modifier and Type	Method and Description
TupleEntry	getArguments() Returns TupleEntry of argument values.
Fields	getDeclaredFields() Return the resolved Fields declared by the current Operation.
TupleEntry	getGroup() Returns the current grouping TupleEntry.
TupleEntryCollector	getOutputCollector() Returns the TupleEntryCollector used to emit result values.

Methods inherited from interface cascading.operation.OperationCall

getArgumentFields, getContext, setContext

Method Detail

getGroup

TupleEntry getGroup()

Returns the current grouping TupleEntry.

Returns:

TupleEntry

getArguments

TupleEntry getArguments()

Returns TupleEntry of argument values.

Will return null unless called in Aggregator.aggregate(cascading.flow.FlowProcess, AggregatorCall).

Note that the returned TupleEntry should not be cached (stored in a Collection), nor should the underlying Tuple instance. Where possible Cascading will re-use both TupleEntry and Tuple instances.

To get a safe copy that can be cached, use TupleEntry.getTupleCopy().

Returns:

TupleEntry

getDeclaredFields

Fields getDeclaredFields()

Return the resolved Fields declared by the current Operation.

Returns:

Fields

getOutputCollector

TupleEntryCollector getOutputCollector()

Returns the TupleEntryCollector used to emit result values.

Will return null unless called in Aggregator.complete(cascading.flow.FlowProcess, AggregatorCall).

Returns:

TupleCollector