Module org.apache.jena.arq
Package org.apache.jena.sparql.expr

Class ExprAggregator

java.lang.Object
org.apache.jena.sparql.expr.ExprNode
org.apache.jena.sparql.expr.ExprAggregator
All Implemented Interfaces:
Expr
public class ExprAggregator extends ExprNode
Group aggregation functions calculated a value during grouping and placed in the output binding. This class is the relationship of an aggregation expression and that variable. Evaluation returns the variable's bound value.

  • Constructor Details

  • Method Details

    • getVar

      public Var getVar()

    • setVar

      public void setVar(Var v)

    • getAggregator

      public Aggregator getAggregator()

    • hashCode

      public int hashCode()
      Description copied from interface: Expr
      Expr are used in both syntax and algebra. There is no syntax to algebra translation step because the parser uses operator precedence to build the right evaluation structure directly.

      The exceptions to this are the NOT EXISTS and EXISTS expressions which involve a query pattern. As a result there are different ways in syntax to produce the same algebra form.

      Two Expr are considered equal if they are equal as algebra expressions. hashCode and equals must implement that.

      There is also equalsBySyntax. Because two different syntax forms can yield the same algebra, but two different algebra forms must be different syntax, equalsBySyntax implies equals (by algebra).

      Hence, different hashCode => not equalsBySyntax.

      Specified by:
      hashCode in interface Expr
      Specified by:
      hashCode in class ExprNode

    • equals

      public boolean equals(Expr other, boolean bySyntax)
      Description copied from interface: Expr
      General equality operation - consider this to be 'protected'
      Specified by:
      equals in interface Expr
      Specified by:
      equals in class ExprNode

    • getExprVar

      public ExprVar getExprVar()
      Description copied from interface: Expr
      Variable (or null)
      Specified by:
      getExprVar in interface Expr
      Overrides:
      getExprVar in class ExprNode

    • asVar

      public Var asVar()
      Description copied from interface: Expr
      Convert to a Var variable.
      Specified by:
      asVar in interface Expr
      Overrides:
      asVar in class ExprNode

    • getAggVar

      public ExprVar getAggVar()

    • asSparqlExpr

      public String asSparqlExpr(SerializationContext sCxt)

    • copySubstitute

      public ExprAggregator copySubstitute(Binding binding)
      Description copied from interface: Expr
      Deep copy with substitution
      Specified by:
      copySubstitute in interface Expr
      Specified by:
      copySubstitute in class ExprNode

    • applyNodeTransform

      public ExprAggregator applyNodeTransform(NodeTransform transform)
      Description copied from interface: Expr
      Rewrite, applying a node->node transformation
      Specified by:
      applyNodeTransform in interface Expr
      Specified by:
      applyNodeTransform in class ExprNode

    • toString

      public String toString()
      Overrides:
      toString in class ExprNode

    • copy

      public Expr copy(Var v)

    • eval

      public NodeValue eval(Binding binding, FunctionEnv env)
      Description copied from interface: Expr
      Evaluate this expression against the binding
      Specified by:
      eval in interface Expr
      Specified by:
      eval in class ExprNode

    • apply

      public Expr apply(ExprTransform transform)

    • visit

      public void visit(ExprVisitor visitor)