org.jaxen.function
Class NumberFunction
java.lang.Object
org.jaxen.function.NumberFunction
- Function
public class NumberFunction
extends java.lang.Object
4.4 number number(object)
The number function converts
its argument to a number as follows:
-
a string that consists of optional whitespace followed by an optional
minus sign followed by a Number followed by
whitespace is converted to the IEEE 754 number that is nearest
(according to the IEEE 754 round-to-nearest rule) to the mathematical
value represented by the string; any other string is converted to NaN
-
boolean true is converted to 1; boolean false is converted to 0
-
a node-set is first converted to a string as if by a call to the string function and then converted
in the same way as a string argument
-
an object of a type other than the four basic types is converted to a
number in a way that is dependent on that type
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.
- bob mcwhirter (bob @ werken.com)
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.
|
static Double | evaluate(Object obj, Navigator nav) - Returns the number value of
obj .
|
static boolean | isNaN(Double val) - Determines whether the argument is not a number (NaN) as defined
by IEEE 754.
|
static boolean | isNaN(double val) - Determines whether the argument is not a number (NaN) as defined
by IEEE 754.
|
NaN
private static final Double NaN
NumberFunction
public NumberFunction()
Create a new NumberFunction
object.
call
public Object call(Context context,
List args)
throws FunctionCallException
Returns the number value of args.get(0)
,
or the number value of the context node if args
is empty.
- call in interface Function
context
- the context at the point in the
expression when the function is calledargs
- a list containing the single item to be converted to a
Double
evaluate
public static Double evaluate(Object obj,
Navigator nav)
Returns the number value of obj
.
obj
- the object to be converted to a numbernav
- the Navigator
used to calculate the string-value
of node-sets
isNaN
public static boolean isNaN(Double val)
Determines whether the argument is not a number (NaN) as defined
by IEEE 754.
- 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.
- true if the value is NaN, false otherwise