Package org.jaxen.function

Class SumFunction

java.lang.Object

org.jaxen.function.SumFunction

All Implemented Interfaces:

Function

public class SumFunction
extends Object
implements Function

4.4 number sum(node-set)

The sum function returns the sum, for each node in the argument node-set, of the result of converting the string-values of the node to a number.

Author:

bob mcwhirter (bob @ werken.com)

See Also:

Section 4.4 of the XPath Specification

Constructor Summary

Constructors

Constructor	Description
SumFunction()	Create a new SumFunction object.

Method Summary

Modifier and Type	Method	Description
Object	call(Context context, List args)	Returns the sum of its arguments.
static Double	evaluate(Object obj, Navigator nav)	Returns the sum of the items in a list.

Methods inherited from class java.lang.Object

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

Constructor Detail

SumFunction

public SumFunction()

Create a new SumFunction object.

Method Detail

call

public Object call(Context context,
                   List args)
            throws FunctionCallException

Returns the sum of its arguments.

Specified by:

call in interface Function

Parameters:

context - the context at the point in the expression when the function is called

args - a list that contains exactly one item, also a List

Returns:

a Double containing the sum of the items in args.get(0)

Throws:

FunctionCallException - if args has more or less than one item; or if the first argument is not a List

evaluate

public static Double evaluate(Object obj,
                              Navigator nav)
                       throws FunctionCallException

Returns the sum of the items in a list. If necessary, each item in the list is first converted to a Double as if by the XPath number() function.

Parameters:

obj - a List of numbers to be summed

nav - ignored

Returns:

the sum of the list

Throws:

FunctionCallException - if obj is not a List