co.cask.cdap.data2.dataset2.lib.cube

Interface Aggregation

All Known Implementing Classes:

DefaultAggregation

public interface Aggregation

Defines an aggregation in DefaultCube.

Aggregation usually defines a list of dimensions, or dimensions that are extracted from the CubeFact when it is added to the Cube. Configuring a Cube to compute an aggregation allows later querying for data based on those dimensions the data is aggregated for. See also CubeQuery.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	accept(co.cask.cdap.api.dataset.lib.cube.CubeFact fact) Filters out CubeFacts which should not be added into this aggregation.
List<String>	getDimensionNames() Defines the dimensions to do the aggregation for.

Method Detail

getDimensionNames

List<String> getDimensionNames()

Defines the dimensions to do the aggregation for.

Depending on the implementation of a Cube, the order of the dimension names can be used as is to form a row key. That in turn may affect the performance of the querying. Usually you want to put most frequently defined dimensions (dimensions with values to slice by in CubeQuery to be in front.

Returns:

list of dimensions (dimensions) to aggregate by

accept

boolean accept(co.cask.cdap.api.dataset.lib.cube.CubeFact fact)

Filters out CubeFacts which should not be added into this aggregation.

Parameters:

fact - fact to test

Returns:

true if fact should be added to the aggregation, false otherwise.