Interface Function

All Known Implementing Classes:
BooleanFunction, CeilingFunction, ConcatFunction, ContainsFunction, CountFunction, DocumentFunction, EndsWithFunction, EvaluateFunction, FalseFunction, FloorFunction, IdFunction, LangFunction, LastFunction, LocaleFunctionSupport, LocalNameFunction, LowerFunction, NameFunction, NamespaceUriFunction, NormalizeSpaceFunction, NotFunction, NumberFunction, PositionFunction, RoundFunction, StartsWithFunction, StringFunction, StringLengthFunction, SubstringAfterFunction, SubstringBeforeFunction, SubstringFunction, SumFunction, TranslateFunction, TrueFunction, UpperFunction
public interface Function
Interface for the extensible function framework.

NOTE: This class is not typically used directly, but is exposed for writers of extended XPath packages.

Implementations of Function are functors which are used to evaluate a function-call within an XPath expression.

Author:
bob mcwhirter
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    Object
    call(Context context, List args)
    Evaluate this function.

  • Method Details

    • call

      Object call(Context context, List args) throws FunctionCallException
      Evaluate this function.
      Parameters:
      context - the context at the point in the expression when the function is called
      args - arguments provided to the function
      Returns:
      the result of evaluating the function; a List (node-set), Double, Boolean, or String
      Throws:
      FunctionCallException - if an XPath error occurs during evaluation; for instance, if the number or type of the arguments is incorrect