Class DistinctValues

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, CallableExpression, InstructionInfo, Locator

public class DistinctValues extends CollatingFunction implements CallableExpression
The XPath 2.0 distinct-values() function
See Also:
  • Constructor Details

    • DistinctValues

      public DistinctValues()
  • Method Details

    • checkArguments

      public void checkArguments(ExpressionVisitor visitor) throws XPathException
      Description copied from class: SystemFunction
      Method called during static type checking
      Overrides:
      checkArguments in class CollatingFunction
      Parameters:
      visitor - the expression visitor
      Throws:
      XPathException - if the arguments are incorrect
    • getAtomicComparer

      public AtomicComparer getAtomicComparer()
      Get the AtomicComparer allocated at compile time.
      Returns:
      the AtomicComparer if one has been allocated at compile time; return null if the collation is not known until run-time
    • makeAtomicComparer

      public AtomicComparer makeAtomicComparer(XPathContext context) throws XPathException
      Get the AtomicComparer, creating it if it was not allocated at compile time.
      Returns:
      the AtomicComparer already allocated if one has been allocated at compile time; otherwise allocate one from knowledge of the collation at run-time
      Throws:
      XPathException
    • iterate

      public SequenceIterator iterate(XPathContext context) throws XPathException
      Evaluate the function to return an iteration of selected values or nodes.
      Overrides:
      iterate in class Expression
      Parameters:
      context - supplies the context for evaluation
      Returns:
      a SequenceIterator that can be used to iterate over the result of the expression
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression
    • call

      public SequenceIterator call(SequenceIterator[] arguments, XPathContext context) throws XPathException
      Description copied from interface: CallableExpression
      Evaluate the expression
      Specified by:
      call in interface CallableExpression
      Parameters:
      arguments - the values of the arguments, supplied as SequenceIterators
      context - the dynamic evaluation context
      Returns:
      the result of the evaluation, in the form of a SequenceIterator
      Throws:
      XPathException - if a dynamic error occurs during the evaluation of the expression