Class SumFunctionCall
java.lang.Object
org.exolab.adaptx.xpath.expressions.PrimaryExpr
org.exolab.adaptx.xpath.expressions.FunctionCall
org.exolab.adaptx.xpath.functions.FunctionCallImpl
org.exolab.adaptx.xpath.functions.SumFunctionCall
- All Implemented Interfaces:
Parameters
,XPathExpression
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
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Field Summary
Fields inherited from class org.exolab.adaptx.xpath.functions.FunctionCallImpl
INVALID_NUMBER_PARAMS, INVALID_RESULT
Fields inherited from class org.exolab.adaptx.xpath.expressions.PrimaryExpr
EXPR, FUNCTION_CALL, LITERAL, NUMBER, VARIABLE_REFERENCE
Fields inherited from interface org.exolab.adaptx.xpath.XPathExpression
BOOLEAN, ERROR, FILTER_EXPR, LOCATION_PATH, NODE_TEST, PATH_EXPR, PRIMARY, STEP, STRING, UNION_EXPR
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptiondouble
computeSum
(NodeSet nodeSet) Computes the sum of the given NodeSet.evaluate
(XPathContext context) Evaluates the expression and returns the XPath result.Methods inherited from class org.exolab.adaptx.xpath.functions.FunctionCallImpl
addParameter, getFunctionName, getParameter, getParameterCount, toString
Methods inherited from class org.exolab.adaptx.xpath.expressions.PrimaryExpr
getExprType, getType
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Constructor Details
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SumFunctionCall
public SumFunctionCall()Creates a new SumFunctionCall
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Method Details
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evaluate
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.
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computeSum
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.
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