org.jaxen.function
Class IdFunction

java.lang.Object
  extended by org.jaxen.function.IdFunction
All Implemented Interfaces:
Function

public class IdFunction
extends Object
implements Function

4.1 node-set id(object)

The id function returns a List of all the elements in the context document that have an ID matching one of a specified list of IDs. How an attribute is determined to be of type ID depends on the navigator, but it normally requires that the attribute be declared to have type ID in the DTD.

There should be no more than one element in any document with a certain ID. However, if there are multiple such elements--i.e. if there are duplicate IDs--then this function selects only the first element in document order with the specified ID.

Author:
Erwin Bolwidt (ejb @ klomp.org), Jérôme Nègre (jerome.negre @ e-xmlmedia.fr)
See Also:
Section 4.1 of the XPath Specification

Constructor Summary
IdFunction()
          Create a new IdFunction object.
 
Method Summary
 Object call(Context context, List args)
          Returns a list of the nodes with the specified IDs.
static List evaluate(List contextNodes, Object arg, Navigator nav)
          Returns a list of the nodes with the specified IDs.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

IdFunction

public IdFunction()
Create a new IdFunction object.

Method Detail

call

public Object call(Context context,
                   List args)
            throws FunctionCallException
Returns a list of the nodes with the specified IDs.

Specified by:
call in interface Function
Parameters:
context - the context at the point in the expression when the function is called
args - a list with exactly one item which is either a string a node-set
Returns:
a List containing the first node in document with each of the specified IDs; or an empty list if there are no such nodes
Throws:
FunctionCallException - if args has more or less than one item

evaluate

public static List evaluate(List contextNodes,
                            Object arg,
                            Navigator nav)
Returns a list of the nodes with the specified IDs.

Parameters:
contextNodes - the context node-set. The first item in this list determines the document in which the search is performed.
arg - the ID or IDs to search for
nav - the navigator used to calculate string-values and search by ID
Returns:
a List containing the first node in document with each of the specified IDs; or an empty list if there are no such nodes


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