Class TupleExprs
java.lang.Object
org.eclipse.rdf4j.query.algebra.helpers.TupleExprs
Utility methods for
TupleExpr objects.- Author:
- Jeen Broekstra
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic booleanstatic booleanVerifies if the suppliedTupleExprcontains aProjectionwith the subquery flag set to true (default).static VarcreateConstVar(Value value) Creates an (anonymous) Var representing a constant value.ReturnsTupleExprchildren of the given node.static StringgetConstVarName(Value value) static booleanVerifies if the supplied expression is a FILTER (NOT) EXISTS operationstatic booleanVerifies if the suppliedTupleExprrepresents a variable scope change.
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Constructor Details
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TupleExprs
public TupleExprs()
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Method Details
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containsSubquery
Verifies if the suppliedTupleExprcontains aProjectionwith the subquery flag set to true (default). If the supplied TupleExpr is aJoinor contains aJoin, projections inside that Join's arguments will not be taken into account.- Parameters:
t- a tuple expression.- Returns:
trueif the TupleExpr contains a subquery projection (outside of a Join),falseotherwise.
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containsExtension
Verifies if the suppliedTupleExprcontains aExtension. If the supplied TupleExpr is aJoinor contains aJoin, aServiceclause or a subquery element, extensions inside that element's argument will not be taken into account.- Parameters:
t- a tuple expression.- Returns:
trueif the TupleExpr contains an Extension (outside of a Join, Service clause, or subquery),falseotherwise.
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isVariableScopeChange
Verifies if the suppliedTupleExprrepresents a variable scope change.- Parameters:
expr- aTupleExpr- Returns:
trueif theTupleExprimplementsVariableScopeChangeand has its scope change flag set totrue,falseotherwise.
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getChildren
ReturnsTupleExprchildren of the given node.- Parameters:
t- a tuple expression.- Returns:
- a list of TupleExpr children.
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createConstVar
Creates an (anonymous) Var representing a constant value. The variable name will be derived from the actual value to guarantee uniqueness.- Parameters:
value-- Returns:
- an (anonymous) Var representing a constant value.
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getConstVarName
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isFilterExistsFunction
Verifies if the supplied expression is a FILTER (NOT) EXISTS operation- Parameters:
expr- a tuple expression- Returns:
- true if the supplied expression is a FILTER (NOT) EXISTS operation, false otherwise.
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