com.bigdata.rdf.sparql.ast.optimizers

Class ASTJoinGroupPartition

java.lang.Object

com.bigdata.rdf.sparql.ast.optimizers.ASTJoinGroupPartition

public class ASTJoinGroupPartition
extends Object

Partition of a join group, defined by a (possibly empty) list of non-optional non-minus nodes, possibly closed by a single optional or minus node. Each partition maintains a set of variables that are definitely bound *after* evaluating the partition. Note that this list is equivalent to the nodes definitely bound *after* evaluating the non-optional non-minus nodes in the partition (i.e., the OPTIONAL/MINUS will not contribute to this list).

Version:

$Id$

Author:

Michael Schmidt

Method Summary

Methods

Modifier and Type	Method and Description
void	addNonOptionalNonMinusNodeToPartition(IGroupMemberNode node) Adds a (non-optional non-minus) node to a join group partition and updates the set of definitely produced variables accordingly.
List<IGroupMemberNode>	extractNodeList(boolean includeOptionalOrMinusNode)
Set<IVariable<?>>	getDefinitelyProduced()
void	removeNodesFromPartition(List<IGroupMemberNode> nodesToRemove) Removes the given set of nodes and updates the internal data structures.
void	replaceNonOptionalNonMinusNodesWith(List<IGroupMemberNode> ordered, boolean recomputeDefinitelyProduced) The new ordered list of non-optional non-minus nodes.

Methods inherited from class java.lang.Object

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

Method Detail

extractNodeList

public List<IGroupMemberNode> extractNodeList(boolean includeOptionalOrMinusNode)

Returns:

the flat (ordered) list of nodes in the partition

addNonOptionalNonMinusNodeToPartition

public void addNonOptionalNonMinusNodeToPartition(IGroupMemberNode node)

Adds a (non-optional non-minus) node to a join group partition and updates the set of definitely produced variables accordingly.

getDefinitelyProduced

public Set<IVariable<?>> getDefinitelyProduced()

Returns:

the variables definitely produced by this partition

replaceNonOptionalNonMinusNodesWith

public void replaceNonOptionalNonMinusNodesWith(List<IGroupMemberNode> ordered,
                                       boolean recomputeDefinitelyProduced)

The new ordered list of non-optional non-minus nodes. If recomputedDefinitelyProduced variables is set to false, the definitely produced variables will not be recomputed (this is a performance tweak which can be exploited when reordering the nodes only, for instance).

Parameters:

ordered -

recomputeDefinitelyProduced -

removeNodesFromPartition

public void removeNodesFromPartition(List<IGroupMemberNode> nodesToRemove)

Removes the given set of nodes and updates the internal data structures.