Class XPathFunctionCall

All Implemented Interfaces:
Serializable, SourceLocator, Container, Expression, InstructionInfoProvider

public class XPathFunctionCall extends FunctionCall
This class is an expression that calls an external function supplied using the JAXP XPathFunction interface
See Also:
  • Constructor Details

    • XPathFunctionCall

      public XPathFunctionCall(XPathFunction function)
      Default constructor
  • Method Details

    • preEvaluate

      public Expression preEvaluate(StaticContext env)
      preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the external function might have side-effects and might use the context)
      Overrides:
      preEvaluate in class FunctionCall
    • checkArguments

      public void checkArguments(StaticContext env) throws XPathException
      Method called by the expression parser when all arguments have been supplied
      Specified by:
      checkArguments in class FunctionCall
      Throws:
      XPathException
    • getIntrinsicDependencies

      public int getIntrinsicDependencies()
      Determine which aspects of the context the expression depends on. XPath external functions are given no access to context information so they cannot have any dependencies on it.
      Overrides:
      getIntrinsicDependencies in class ComputedExpression
      Returns:
      a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
    • iterate

      public SequenceIterator iterate(XPathContext context) throws XPathException
      Evaluate the function.
      Specified by:
      iterate in interface Expression
      Overrides:
      iterate in class ComputedExpression
      Parameters:
      context - The context in which the function is to be evaluated
      Returns:
      a Value representing the result of the function.
      Throws:
      XPathException - if the function cannot be evaluated.
    • call

      public SequenceIterator call(ValueRepresentation[] argValues, XPathContext context) throws XPathException
      Call an extension function previously identified using the bind() method. A subclass can override this method.
      Parameters:
      argValues - The values of the arguments
      Returns:
      The value returned by the extension function
      Throws:
      XPathException
    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Determine the data type of the expression, if possible. All expressions return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.

      This method will always return a result, though it may be the best approximation that is available at the time.

      Parameters:
      th -
      Returns:
      the item type
    • computeCardinality

      public int computeCardinality()
      Determine the cardinality of the result
      Specified by:
      computeCardinality in class ComputedExpression
      Returns:
      ZERO_OR_MORE (we don't know)