Package org.jaxen.function

Class StringFunction

java.lang.Object

org.jaxen.function.StringFunction

All Implemented Interfaces:

Function

public class StringFunction
extends Object
implements Function

4.2 string string(object)

The string function converts an object to a string as follows:

• A node-set is converted to a string by returning the string-value of the node in the node-set that is first in document order. If the node-set is empty, an empty string is returned.

• A number is converted to a string as follows

  • NaN is converted to the string NaN

  • positive zero is converted to the string 0

  • negative zero is converted to the string 0

  • positive infinity is converted to the string Infinity

  • negative infinity is converted to the string -Infinity

  • if the number is an integer, the number is represented in decimal form as a Number with no decimal point and no leading zeros, preceded by a minus sign (-) if the number is negative

  • otherwise, the number is represented in decimal form as a Number including a decimal point with at least one digit before the decimal point and at least one digit after the decimal point, preceded by a minus sign (-) if the number is negative; there must be no leading zeros before the decimal point apart possibly from the one required digit immediately before the decimal point; beyond the one required digit after the decimal point there must be as many, but only as many, more digits as are needed to uniquely distinguish the number from all other IEEE 754 numeric values.

• The boolean false value is converted to the string false. The boolean true value is converted to the string true.

• An object of a type other than the four basic types is converted to a string 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.

Author:

bob mcwhirter (bob @ werken.com)

See Also:

Section 4.2 of the XPath Specification

Constructor Summary

Constructors

Constructor	Description
StringFunction()	Create a new StringFunction object.

Method Summary

Modifier and Type	Method	Description
Object	call(Context context, List args)	Returns the string-value of args.get(0) or of the context node if args is empty.
static String	evaluate(Object obj, Navigator nav)	Returns the XPath string-value of obj.

Methods inherited from class java.lang.Object

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

Constructor Detail

StringFunction

public StringFunction()

Create a new StringFunction object.

Method Detail

call

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

Returns the string-value of args.get(0) or of the context node if args is empty.

Specified by:

call in interface Function

Parameters:

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

args - list with zero or one element

Returns:

a String

Throws:

FunctionCallException - if args has more than one item

evaluate

public static String evaluate(Object obj,
                              Navigator nav)

Returns the XPath string-value of obj. This operation is only defined if obj is a node, node-set, String, Number, or Boolean. For other types this function returns the empty string.

Parameters:

obj - the node, node-set, string, number, or boolean whose string-value is calculated

nav - the navigator used to calculate the string-value

Returns:

a String. May be empty but is never null.