Package org.eclipse.rdf4j.query.algebra.helpers

Class TupleExprs

java.lang.Object
org.eclipse.rdf4j.query.algebra.helpers.TupleExprs
public class TupleExprs extends Object
Utility methods for TupleExpr objects.
Author:
Jeen Broekstra

  • Constructor Details

    • TupleExprs

      public TupleExprs()

  • Method Details

    • containsSubquery

      public static boolean containsSubquery(TupleExpr t)
      Verifies if the supplied TupleExpr contains a Projection with the subquery flag set to true (default). If the supplied TupleExpr is a Join or contains a Join, projections inside that Join's arguments will not be taken into account.
      Parameters:
      t - a tuple expression.
      Returns:
      true if the TupleExpr contains a subquery projection (outside of a Join), false otherwise.

    • containsExtension

      public static boolean containsExtension(TupleExpr t)
      Verifies if the supplied TupleExpr contains a Extension. If the supplied TupleExpr is a Join or contains a Join, a Service clause or a subquery element, extensions inside that element's argument will not be taken into account.
      Parameters:
      t - a tuple expression.
      Returns:
      true if the TupleExpr contains an Extension (outside of a Join, Service clause, or subquery), false otherwise.

    • isVariableScopeChange

      public static boolean isVariableScopeChange(TupleExpr expr)
      Verifies if the supplied TupleExpr represents a variable scope change.
      Parameters:
      expr - a TupleExpr
      Returns:
      true if the TupleExpr implements VariableScopeChange and has its scope change flag set to true, false otherwise.

    • getChildren

      public static List<TupleExpr> getChildren(TupleExpr t)
      Returns TupleExpr children of the given node.
      Parameters:
      t - a tuple expression.
      Returns:
      a list of TupleExpr children.

    • createConstVar

      public static Var createConstVar(Value value)
      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.

    • getConstVarName

      public static String getConstVarName(Value value)

    • isFilterExistsFunction

      public static boolean isFilterExistsFunction(TupleExpr expr)
      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.