org.jaxen

Interface Function

Known Implementing Classes:
BooleanFunction, CeilingFunction, ConcatFunction, ContainsFunction, CountFunction, DocumentFunction, EndsWithFunction, EvaluateFunction, FalseFunction, FloorFunction, IdFunction, LangFunction, LastFunction, LocaleFunctionSupport, LocalNameFunction, LowerFunction, MatrixConcatFunction, 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:
FunctionContext

Method Summary

Object
call(Context context, List args)
Evaluate this function.

Method Details

call

public 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