com.pervasive.datarush.operators.group

Interface Aggregator

public interface Aggregator

Interface to be implemented by implementations of aggregations; consumers of the API should generally not need to implement this interface.

Method Summary

Modifier and Type	Method and Description
void	accumulate() Adds the current row to the internal counters.
void	combineInternals(ReadableStorage internals) Adds the internal counters of another aggregator this this aggregator's internal counters.
ScalarTokenType[]	getInternalTypes() Returns the types of the internal counters of this aggregator
ScalarTokenType	getOutputType() Returns the output type of this aggregator.
void	reset() Resets the internal counters
void	setInputs(ScalarValued[] inputs) Binds the input values for this aggregator.
void	storeFinalResult(ScalarSettable output) Outputs the final result into the specified ScalarSettable.
void	storeInternals(WriteableStorage internals) Stores the internal counters of this aggregator.
void	updateInternals(ReadableStorage readView, WriteableStorage writeView) Updates an existing internals object with new values.

Method Detail

setInputs

void setInputs(ScalarValued[] inputs)

Binds the input values for this aggregator.

Parameters:

inputs - the sources of values to aggregate

accumulate

void accumulate()

Adds the current row to the internal counters. The values of the current row are available from the previous call to setInputs(ScalarValued[]).

reset

void reset()

Resets the internal counters

getInternalTypes

ScalarTokenType[] getInternalTypes()

Returns the types of the internal counters of this aggregator

Returns:

the types of the internal counters of this aggregator

combineInternals

void combineInternals(ReadableStorage internals)

Adds the internal counters of another aggregator this this aggregator's internal counters.

Parameters:

internals - the internal counters of the other aggregator. Will match the types returned by getInternalTypes().

storeInternals

void storeInternals(WriteableStorage internals)

Stores the internal counters of this aggregator.

Parameters:

internals - Storage in which to store this aggregators internals. Will match the types returned by getInternalTypes().

updateInternals

void updateInternals(ReadableStorage readView,
                     WriteableStorage writeView)

Updates an existing internals object with new values. Most implementations will simply call storeInternals(WriteableStorage) as this is always safe. For GC efficiency, implementations that have mutable components may wish to copy over those existing components rather than cloning.

Parameters:

readView - storage to use for loading internal counters

writeView - storage to use for storage internal counters

storeFinalResult

void storeFinalResult(ScalarSettable output)

Outputs the final result into the specified ScalarSettable.

Parameters:

output - the output where the result is to be stored

getOutputType

ScalarTokenType getOutputType()

Returns the output type of this aggregator.

Returns:

the output type of this aggregator.