mondrian.rolap
Class RolapAggregator

java.lang.Object
  mondrian.olap.EnumeratedValues.BasicValue
      mondrian.rolap.RolapAggregator

All Implemented Interfaces:

Aggregator, EnumeratedValues.Value

Direct Known Subclasses:

RolapAggregator.BaseAggor

public abstract class RolapAggregator
extends EnumeratedValues.BasicValue
implements Aggregator

Describes an aggregation operator, such as "sum" or "count".

Since:

Jul 9, 2003

Author:

jhyde

Nested Class Summary

static class	RolapAggregator.AvgFromAvg Aggregator used for aggregate tables implementing the average aggregator.
static class	RolapAggregator.AvgFromSum Aggregator used for aggregate tables implementing the average aggregator.
protected static class	RolapAggregator.BaseAggor This is the base class for implementing aggregators over sum and average columns in an aggregate table.
static class	RolapAggregator.SumFromAvg This is an aggregator used for aggregate tables implementing the sum aggregator.

Field Summary

static RolapAggregator	Avg
static RolapAggregator	Count
static RolapAggregator	DistinctCount
static EnumeratedValues<RolapAggregator>	enumeration List of all valid aggregation operators.
static RolapAggregator	Max
static RolapAggregator	Min
static RolapAggregator	Sum

Fields inherited from class mondrian.olap.EnumeratedValues.BasicValue

description, name, ordinal

Constructor Summary

RolapAggregator(String name, int ordinal, boolean distinct)

Method Summary

Object	aggregate(List<Object> rawData) Applies this aggregator over a raw list of objects for a rollup operation.
String	getExpression(String operand) Returns the expression to apply this aggregator to an operand.
RolapAggregator	getNonDistinctAggregator() If this is a distinct aggregator, returns the corresponding non-distinct aggregator, otherwise throws an error.
Aggregator	getRollup() Returns the aggregator used to roll up.
boolean	isDistinct()
boolean	supportsFastAggregates(Dialect.Datatype dataType) By default, fast rollup is not supported for all classes.

Methods inherited from class mondrian.olap.EnumeratedValues.BasicValue

equals, getDescription, getName, getOrdinal, toString, unexpected

Methods inherited from class java.lang.Object

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

Methods inherited from interface mondrian.olap.Aggregator

aggregate

Field Detail

Sum

public static final RolapAggregator Sum

Count

public static final RolapAggregator Count

Min

public static final RolapAggregator Min

Max

public static final RolapAggregator Max

Avg

public static final RolapAggregator Avg

DistinctCount

public static final RolapAggregator DistinctCount

enumeration

public static final EnumeratedValues<RolapAggregator> enumeration

List of all valid aggregation operators.

Constructor Detail

RolapAggregator

public RolapAggregator(String name,
                       int ordinal,
                       boolean distinct)

Method Detail

isDistinct

public boolean isDistinct()

getExpression

public String getExpression(String operand)

Returns the expression to apply this aggregator to an operand. For example, getExpression("emp.sal") returns "sum(emp.sal)".

getNonDistinctAggregator

public RolapAggregator getNonDistinctAggregator()

If this is a distinct aggregator, returns the corresponding non-distinct aggregator, otherwise throws an error.

getRollup

public Aggregator getRollup()

Returns the aggregator used to roll up. By default, aggregators roll up themselves.

Specified by:

getRollup in interface Aggregator

Returns:

aggregator used to combine sub-totals into a grand-total

supportsFastAggregates

public boolean supportsFastAggregates(Dialect.Datatype dataType)

By default, fast rollup is not supported for all classes.

Specified by:

supportsFastAggregates in interface Aggregator

Parameters:

dataType - The datatype of the object we would like to rollup.

Returns:

Whether this aggregator supports fast aggregation

aggregate

public Object aggregate(List<Object> rawData)

Description copied from interface: Aggregator

Applies this aggregator over a raw list of objects for a rollup operation. This is useful when the values are already resolved and we are dealing with a raw SegmentBody object.

Only gets called if Aggregator.supportsFastAggregates(mondrian.spi.Dialect.Datatype) is true.

This is only invoked for rollup operations.

Specified by:

aggregate in interface Aggregator

Parameters:

rawData - An array of values in its raw form, to be aggregated.

Returns:

A rolled up value of the raw data. if the object type is not supported.