mondrian.rolap

Class DescendantsConstraint

java.lang.Object

mondrian.rolap.DescendantsConstraint

All Implemented Interfaces:

SqlConstraint, TupleConstraint

class DescendantsConstraint
extends Object
implements TupleConstraint

TupleConstaint which restricts the result of a tuple sqlQuery to a set of parents. All parents must belong to the same level.

Since:

Nov 10, 2005

Author:

av

Field Summary

Fields

Modifier and Type	Field and Description
(package private) MemberChildrenConstraint	mcc
(package private) List<RolapMember>	parentMembers

Constructor Summary

Constructors

Constructor and Description
DescendantsConstraint(List<RolapMember> parentMembers, MemberChildrenConstraint mcc) Creates a DescendantsConstraint.

Method Summary

Modifier and Type	Method and Description
void	addConstraint(SqlQuery sqlQuery, RolapCube baseCube, AggStar aggStar) Modifies a Level.Members query.
void	addLevelConstraint(SqlQuery sqlQuery, RolapCube baseCube, AggStar aggStar, RolapLevel level) Will be called multiple times for every "group by" level in Level.Members query, i.e.
Object	getCacheKey() Returns a key that becomes part of the key for caching the result of the SQL query.
Evaluator	getEvaluator()
MemberChildrenConstraint	getMemberChildrenConstraint(RolapMember parent) When the members of a level are fetched, the result is grouped by into parents and their children.
boolean	supportsAggTables()

Methods inherited from class java.lang.Object

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

Field Detail

parentMembers

List<RolapMember> parentMembers

mcc

MemberChildrenConstraint mcc

Constructor Detail

DescendantsConstraint

public DescendantsConstraint(List<RolapMember> parentMembers,
                             MemberChildrenConstraint mcc)

Creates a DescendantsConstraint.

Parameters:

parentMembers - list of parents all from the same level

mcc - the constraint that would return the children for each single parent

Method Detail

addConstraint

public void addConstraint(SqlQuery sqlQuery,
                          RolapCube baseCube,
                          AggStar aggStar)

Description copied from interface: TupleConstraint

Modifies a Level.Members query.

Specified by:

addConstraint in interface TupleConstraint

Parameters:

sqlQuery - the query to modify

baseCube - base cube for virtual cube constraints

aggStar - aggregate star to use

addLevelConstraint

public void addLevelConstraint(SqlQuery sqlQuery,
                               RolapCube baseCube,
                               AggStar aggStar,
                               RolapLevel level)

Description copied from interface: TupleConstraint

Will be called multiple times for every "group by" level in Level.Members query, i.e. the level that contains the members and all parent levels except All. If the condition requires so, it may join the levels table to the fact table.

Specified by:

addLevelConstraint in interface TupleConstraint

Parameters:

sqlQuery - the query to modify

baseCube - base cube for virtual cube constraints

aggStar - Aggregate table, or null if query is against fact table

level - the level which is accessed in the Level.Members query

getMemberChildrenConstraint

public MemberChildrenConstraint getMemberChildrenConstraint(RolapMember parent)

Description copied from interface: TupleConstraint

When the members of a level are fetched, the result is grouped by into parents and their children. These parent/children are stored in the parent/children cache, whose key consists of the parent and the MemberChildrenConstraint#hashKey(). So we need a matching MemberChildrenConstraint to store the parent with its children into the parent/children cache.

The returned MemberChildrenConstraint must be one that would have returned the same children for the given parent as the MemberLevel query has found for that parent.

If null is returned, the parent/children will not be cached (but the level/members still will be).

Specified by:

getMemberChildrenConstraint in interface TupleConstraint

getCacheKey

public Object getCacheKey()

Returns a key that becomes part of the key for caching the result of the SQL query. So SqlConstraint instances that produce the same SQL resultset must return equal keys in terms of equal() and hashCode().

This implementation returns null, because descendants is not cached.

Specified by:

getCacheKey in interface SqlConstraint

Returns:

valid key or null to prevent the result from being cached

getEvaluator

public Evaluator getEvaluator()

Specified by:

getEvaluator in interface TupleConstraint

Returns:

the evaluator currently associated with the constraint; null if there is no associated evaluator

supportsAggTables

public boolean supportsAggTables()

Specified by:

supportsAggTables in interface TupleConstraint

Returns:

true if the constraint can leverage an aggregate table