org.exolab.adaptx.xpath.functions

Class SumFunctionCall

public class SumFunctionCall extends FunctionCallImpl

A class that represents the XPath 1.0 sum function call. The Sum function takes as an argument an experession which evaluates to a node-set. Each node in the node-set will have it's string-value converted into a number. Each resulting number will then added together to compute the sum. Nodes whose string value is the empty-string will be ignored. If any node within the node-set has a non-zero length string value that cannot be sucessfully converted to a number, an XPathException will be thrown.

Version: $Revision: 3736 $

Author: Keith Visco

Constructor Summary
SumFunctionCall()
Creates a new SumFunctionCall
Method Summary
doublecomputeSum(NodeSet nodeSet)
Computes the sum of the given NodeSet.
XPathResultevaluate(XPathContext context)
Evaluates the expression and returns the XPath result.

Constructor Detail

SumFunctionCall

public SumFunctionCall()
Creates a new SumFunctionCall

Method Detail

computeSum

public double computeSum(NodeSet nodeSet)
Computes the sum of the given NodeSet. The sum is computed by adding up the number values of each node within the node set. If any non-numeric node values are encountered, an XPathException will be thrown.

Parameters: nodeSet the NodeSet to the compute the sum of

Returns: the sum as a double

Throws: XPathException when a non-numeric value is encountered.

evaluate

public XPathResult evaluate(XPathContext context)
Evaluates the expression and returns the XPath result.

Parameters: context The XPathContext to use during evaluation.

Returns: The XPathResult (not null).

Throws: XPathException if an error occured while evaluating this expression.