mondrian.rolap.agg
Class SegmentBuilder

java.lang.Object
  mondrian.rolap.agg.SegmentBuilder

public class SegmentBuilder
extends Object

Helper class that contains methods to convert between Segment and SegmentHeader, and also SegmentWithData and SegmentBody.

Author:

LBoudreau

Nested Class Summary

static interface	SegmentBuilder.SegmentConverter Functor to convert a segment header and body into a SegmentWithData.
static class	SegmentBuilder.SegmentConverterImpl Implementation of SegmentBuilder.SegmentConverter that uses an AggregationKey and CellRequest as context to convert a SegmentHeader.
static class	SegmentBuilder.StarSegmentConverter Implementation of SegmentBuilder.SegmentConverter that uses a star measure and a list of StarPredicate.

Constructor Summary

SegmentBuilder()

Method Summary

static SegmentWithData	addData(Segment segment, SegmentBody sb) Converts a segment plus a SegmentBody into a SegmentWithData.
static boolean	isSubset(SegmentHeader header, Segment segment) Tells if the passed segment is a subset of this segment and could be used for a rollup in cache operation.
static Pair<SegmentHeader,SegmentBody>	rollup(Map<SegmentHeader,SegmentBody> map, Set<String> keepColumns, BitKey targetBitkey, Aggregator rollupAggregator) Given a collection of segments, all of the same dimensionality, rolls up to create a segment with reduced dimensionality.
static List<SegmentColumn>	toConstrainedColumns(Collection<StarColumnPredicate> predicates)
static List<SegmentColumn>	toConstrainedColumns(StarColumnPredicate[] predicates)
static SegmentHeader	toHeader(Segment segment) Creates a SegmentHeader object describing the supplied Segment object.
static Segment	toSegment(SegmentHeader header, RolapStar star, BitKey constrainedColumnsBitKey, RolapStar.Column[] constrainedColumns, RolapStar.Measure measure, List<StarPredicate> compoundPredicates) Creates a segment from a SegmentHeader.

Methods inherited from class java.lang.Object

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

Constructor Detail

SegmentBuilder

public SegmentBuilder()

Method Detail

addData

public static SegmentWithData addData(Segment segment,
                                      SegmentBody sb)

Converts a segment plus a SegmentBody into a SegmentWithData.

Parameters:

segment - Segment

sb - Segment body

Returns:

SegmentWithData

toSegment

public static Segment toSegment(SegmentHeader header,
                                RolapStar star,
                                BitKey constrainedColumnsBitKey,
                                RolapStar.Column[] constrainedColumns,
                                RolapStar.Measure measure,
                                List<StarPredicate> compoundPredicates)

Creates a segment from a SegmentHeader. The star, constrainedColsBitKey, constrainedColumns and measure arguments are a helping hand, because we know what we were looking for.

Parameters:

header - The header to convert.

star - Star

constrainedColumnsBitKey - Constrained columns

constrainedColumns - Constrained columns

measure - Measure

Returns:

Segment

rollup

public static Pair<SegmentHeader,SegmentBody> rollup(Map<SegmentHeader,SegmentBody> map,
                                                     Set<String> keepColumns,
                                                     BitKey targetBitkey,
                                                     Aggregator rollupAggregator)

Given a collection of segments, all of the same dimensionality, rolls up to create a segment with reduced dimensionality.

Parameters:

map - Source segment headers and bodies

keepColumns - A list of column names to keep as part of the rolled up segment.

targetBitkey - The column bit key to match with the resulting segment.

rollupAggregator - The aggregator to use to rollup.

Returns:

Segment header and body of requested dimensionality

isSubset

public static boolean isSubset(SegmentHeader header,
                               Segment segment)

Tells if the passed segment is a subset of this segment and could be used for a rollup in cache operation.

Parameters:

segment - A segment which might be a subset of the current segment.

Returns:

True or false.

toConstrainedColumns

public static List<SegmentColumn> toConstrainedColumns(StarColumnPredicate[] predicates)

toConstrainedColumns

public static List<SegmentColumn> toConstrainedColumns(Collection<StarColumnPredicate> predicates)

toHeader

public static SegmentHeader toHeader(Segment segment)

Creates a SegmentHeader object describing the supplied Segment object.

Parameters:

segment - A segment object for which we want to generate a SegmentHeader.

Returns:

A SegmentHeader describing the supplied Segment object.