net.christopherschultz.evaluator.function
Class LengthFunction

java.lang.Object
  net.christopherschultz.evaluator.StandardFunction
      net.christopherschultz.evaluator.function.LengthFunction

All Implemented Interfaces:

Function

public class LengthFunction
extends StandardFunction

Returns the length of the specified array or collection.

Usage: length(a:array or list)

This function respects the value of MathFunction.NULL_RETURNS_NULL; if the array or list argument is null, the behavior is defined by the current value of MathExpression.NULL_RETURNS_NULL. If the property is set to true, then a null is returned. If the property is set to false, then zero is returned (since null contains no elements).

Version:

$Revision: 1.2 $ $Date: 2008-06-20 22:58:48 $

Author:

Chris Schultz

Constructor Summary

LengthFunction()

Method Summary

Object

call(EvaluationContext ec, String functionName, Object[] args) Calls this function with standard argument evaluation semantics.

Methods inherited from class net.christopherschultz.evaluator.StandardFunction

call, getExpressionValue, getExpressionValueArray, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

LengthFunction

public LengthFunction()

Method Detail

call

public Object call(EvaluationContext ec,
                   String functionName,
                   Object[] args)
            throws EvaluationException

Description copied from class: StandardFunction

Calls this function with standard argument evaluation semantics.

Specified by:

call in class StandardFunction

Parameters:

ec - The EvaluationContext in which this function is being called.

functionName - The name of the function being invoked.

args - The argument values to pass to this function.

Returns:

The result of the function.

Throws:

EvaluationException - If there is an error during function execution.