org.semanticweb.kaon2.extensionapi.builtins
Class ExpressionEvaluator

java.lang.Object
  org.semanticweb.kaon2.extensionapi.builtins.ExpressionEvaluator

public abstract class ExpressionEvaluator
extends java.lang.Object

Implements a builtin function that performs a certain operation on literal values that is invoked through kaon2:evaluate or kaon2:ifTrue predicates.

Constructor Summary

ExpressionEvaluator()

Method Summary

abstract java.lang.Object	evaluate(java.lang.Object[] boundValues) Invoked to evaluate the operation on given objects.
static <T extends ExpressionEvaluator> void	registerBuiltinFunction(java.lang.String functionName, java.lang.Class<T> evaluatorClass) Registers a builtin function under given name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExpressionEvaluator

public ExpressionEvaluator()

Method Detail

evaluate

public abstract java.lang.Object evaluate(java.lang.Object[] boundValues)
                                   throws KAON2Exception

Invoked to evaluate the operation on given objects.

Parameters:

boundValues - the array of arguments

Returns:

the value of the evaluator

Throws:

KAON2Exception - thrown if there is an error in evaluating the object

registerBuiltinFunction

public static <T extends ExpressionEvaluator> void registerBuiltinFunction(java.lang.String functionName,
                                                                           java.lang.Class<T> evaluatorClass)

Registers a builtin function under given name. The evaluatorClass parameter should point to the class implementing the evaluator. The class must have a public constructor accepting ExpressionEvaluator... as arguments.

Parameters:

functionName - the name of the function

evaluatorClass - the class of the evaluator