com.bigdata.rdf.sparql.ast

Interface IVariableBindingRequirements

All Known Subinterfaces:

IGroupMemberNode, IGroupNode<E>, IReorderableNode, IStatementContainer

All Known Implementing Classes:

AbstractFromToGraphManagement, AbstractGraphDataUpdate, AbstractOneGraphManagement, AbstractStatementContainer, AddGraph, ArbitraryLengthPathNode, AssignmentNode, BindingsClause, ClearGraph, ConstructNode, CopyGraph, CreateEntailments, CreateGraph, DeleteData, DeleteInsertGraph, DisableEntailments, DropEntailments, DropGraph, EnableEntailments, FilterNode, GraphManagement, GraphPatternGroup, GraphUpdate, GroupMemberNodeBase, GroupMemberValueExpressionNodeBase, GroupNodeBase, InsertData, JoinGroupNode, LoadGraph, MoveGraph, NamedSubqueryInclude, NamedSubqueryRoot, PropertyPathNode, PropertyPathUnionNode, QuadData, ServiceNode, StatementPatternNode, SubqueryBase, SubqueryRoot, UnionNode, Update, UpdateRoot, ZeroLengthPathNode

public interface IVariableBindingRequirements

Interface describing constraints and desiderata w.r.t. variable bindings that should, must, or must not be present at the time when executing the construct.

Version:

$Id$

Author:

Michael Schmidt

Method Summary

Methods

Modifier and Type	Method and Description
Set<IVariable<?>>	getDesiredBound(StaticAnalysis sa) Get variables that are not required to be bound, but desired in the sense that we want them to be bound when evaluating the construct.
Set<IVariable<?>>	getRequiredBound(StaticAnalysis sa) Return the variables used in the node that *must* be bound prior to evaluating the node.

Method Detail

getRequiredBound

Set<IVariable<?>> getRequiredBound(StaticAnalysis sa)

Return the variables used in the node that *must* be bound prior to evaluating the node. For instance, when evaluation a SPARQL 1.1 service and the endpoint is specified through a variable, then this variable must be bound in order to identify the endpoint to which the query is to be sent. By *must* be bound we mean that, if it is possible to bring the variables in a join group in order such that they are bound when executing the construct (e.g., think of a FILTER), then we *must* consider that. However, when the IVariableBindingRequirements#getRequiredBound() interface cannot be satisified, the query may still be valid and return results (for the SPARQL 1.1 service example mentioned above, it may not, for the FILTER it may). The set of these variables must be disjoint from IVariableBindingRequirements#getRequiredUnound().

Returns:

the set of variables that must be bound prior to evaluation

getDesiredBound

Set<IVariable<?>> getDesiredBound(StaticAnalysis sa)

Get variables that are not required to be bound, but desired in the sense that we want them to be bound when evaluating the construct. In general, the more variables are bound, the better, but this might differ for certain constructs. Should only report variables that are *not* reported through method getRequiredBound(StaticAnalysis).

Returns:

the set of variables that are desires to be bound, but not required