Package net.sf.saxon.functions

Class ContextDependentUserFunction

java.lang.Object
net.sf.saxon.functions.AbstractFunction
net.sf.saxon.functions.ContextDependentUserFunction
All Implemented Interfaces:
Callable, IContextAccessorFunction, FunctionItem, GroundedValue, Item, Sequence
public class ContextDependentUserFunction extends AbstractFunction implements IContextAccessorFunction

  • Constructor Details

    • ContextDependentUserFunction

      public ContextDependentUserFunction(UserFunction underlyingFunction, int arity)

  • Method Details

    • dependsOnContext

      public boolean dependsOnContext()
      Description copied from interface: IContextAccessorFunction
      Ask whether this function is actually dependent on the dynamic context
      Specified by:
      dependsOnContext in interface IContextAccessorFunction
      Returns:
      true if the function cannot be used unless the dynamic context is first bound

    • call

      public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException
      Call the Callable.
      Specified by:
      call in interface Callable
      Parameters:
      context - the dynamic evaluation context
      arguments - the values of the arguments, supplied as Sequences.

      Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

      If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

      It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

      Returns:
      the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.
      Throws:
      XPathException - if a dynamic error occurs during the evaluation of the expression

    • bindContext

      public FunctionItem bindContext(XPathContext context) throws XPathException
      Bind context information to appear as part of the function's closure. If this method has been called, the supplied context will be used in preference to the context at the point where the function is actually called.
      Specified by:
      bindContext in interface IContextAccessorFunction
      Parameters:
      context - the context to which the function applies. Must not be null.
      Throws:
      XPathException

    • getFunctionItemType

      public FunctionItemType getFunctionItemType()
      Get the item type of the function item
      Specified by:
      getFunctionItemType in interface FunctionItem
      Returns:
      the function item's type

    • getFunctionName

      public StructuredQName getFunctionName()
      Get the name of the function, or null if it is anonymous
      Specified by:
      getFunctionName in interface FunctionItem
      Returns:
      the function name, or null for an anonymous inline function

    • getArity

      public int getArity()
      Get the arity of the function
      Specified by:
      getArity in interface FunctionItem
      Returns:
      the number of arguments in the function signature

    • getDescription

      public String getDescription()
      Get a description of this function for use in error messages. For named functions, the description is the function name (as a lexical QName). For others, it might be, for example, "inline function", or "partially-applied ends-with function".
      Specified by:
      getDescription in interface FunctionItem
      Returns:
      a description of the function for use in error messages