Package net.sf.saxon.functions

Class Available

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.Available
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, XSLTFunction, InstructionInfo, Locator
public class Available extends SystemFunction implements XSLTFunction
This class supports the XSLT element-available and function-available functions.
See Also:

  • Field Details

  • Constructor Details

    • Available

      public Available()

  • 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 SystemFunction
      Parameters:
      visitor - the expression visitor
      Throws:
      XPathException

    • preEvaluate

      public Expression preEvaluate(ExpressionVisitor visitor) throws XPathException
      preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)
      Overrides:
      preEvaluate in class FunctionCall
      Parameters:
      visitor - the expression visitor
      Returns:
      the result of the early evaluation, or the original expression, or potentially a simplified expression
      Throws:
      XPathException

    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Run-time evaluation. This is the only thing in the spec that requires information about in-scope functions to be available at run-time. However, we keep it because it's handy for some other things such as saxon:evaluate().
      Specified by:
      evaluateItem in interface EvaluableItem
      Overrides:
      evaluateItem in class Expression
      Parameters:
      context - The context in which the expression is to be evaluated
      Returns:
      the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression