org.jaxen.function

Class NumberFunction

public class NumberFunction extends Object implements Function

4.4 number number(object)

The number function converts its argument to a number as follows:

If the argument is omitted, it defaults to a node-set with the context node as its only member.

NOTE: The number function should not be used for conversion of numeric data occurring in an element in an XML document unless the element is of a type that represents numeric data in a language-neutral format (which would typically be transformed into a language-specific format for presentation to a user). In addition, the number function cannot be used unless the language-neutral format used by the element is consistent with the XPath syntax for a Number.

Author: bob mcwhirter (bob @ werken.com)

See Also: Section 4.4 of the XPath Specification

Field Summary
static DoubleNaN
Constructor Summary
NumberFunction()
Create a new NumberFunction object.
Method Summary
Objectcall(Context context, List args)
Returns the number value of args.get(0), or the number value of the context node if args is empty.
static Doubleevaluate(Object obj, Navigator nav)
Returns the number value of obj.
static booleanisNaN(double val)
Determines whether the argument is not a number (NaN) as defined by IEEE 754.
static booleanisNaN(Double val)
Determines whether the argument is not a number (NaN) as defined by IEEE 754.

Field Detail

NaN

private static final Double NaN

Constructor Detail

NumberFunction

public NumberFunction()
Create a new NumberFunction object.

Method Detail

call

public Object call(Context context, List args)
Returns the number value of args.get(0), or the number value of the context node if args is empty.

Parameters: context the context at the point in the expression when the function is called args a list containing the single item to be converted to a Double

Returns: a Double

Throws: FunctionCallException if args has more than one item

evaluate

public static Double evaluate(Object obj, Navigator nav)
Returns the number value of obj.

Parameters: obj the object to be converted to a number nav the Navigator used to calculate the string-value of node-sets

Returns: a Double

isNaN

public static boolean isNaN(double val)
Determines whether the argument is not a number (NaN) as defined by IEEE 754.

Parameters: val the double to test

Returns: true if the value is NaN, false otherwise

isNaN

public static boolean isNaN(Double val)
Determines whether the argument is not a number (NaN) as defined by IEEE 754.

Parameters: val the Double to test

Returns: true if the value is NaN, false otherwise