Agustina,
JXPath 1.1 must have had a bug in this area. The call to context.getValue() is supposed to throw an exception when it cannot find the requested xpath, unless of course you have called context.setLenient(true), which will make it return null in the same situation. That's a general rule - to get null for missing paths, call context.setLenient(true) first.
I hope this helps,
- Dmitri
----- Original Message ----- From: "Agustina Dagnino" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 16, 2004 10:39 AM
Subject: jxpath - changes in release 1.2 in collection handling?
I recently changed from jxpath release 1.1 to 1.2 and have found that changes
in the new release make it incompatible with my software.
The main issue is as follows:
I have an object with a collection.
Whenever I search for a particular object in the collection I get the following
behaviour (if the object I�m looking for is not present in the collection):
Release 1.1.- returns a null value
Release 1.2.- throws a JXPathException
Example:
------------------------------------------------
import java.util.ArrayList; import java.util.Collection;
import org.apache.commons.jxpath.JXPathContext;
/** * MyObject */ public class MyObject { private Collection myCollection ; private String attribute ;
public Collection getMyCollection() { if( myCollection==null ) { myCollection = new ArrayList(); } return myCollection; }
public void setMyCollection( Collection myCollection ) { this.myCollection = myCollection ; }
public String getAttribute() { return attribute ; }
public void setAttribute( String attribute ) { this.attribute = attribute ; }
public static void main(String[] args) { MyObject myObject = new MyObject(); MyObject anotherObject = new MyObject();
myObject.getMyCollection().add(anotherObject);
JXPathContext context = JXPathContext.newContext(myObject) ;
System.out.println( context.getValue("myCollection[attribute='AA']") ); }
}
------------------------------------------------
release 1.1 produces a null output, while release 1.2 generates this stack
trace:
org.apache.commons.jxpath.JXPathException: No value for xpath: myCollection[attribute='AA']
at org.apache.commons.jxpath.ri.JXPathContextReferenceImpl.getValue(JXPathContextReferenceImpl.java:318)
at org.apache.commons.jxpath.ri.JXPathContextReferenceImpl.getValue(JXPathContextReferenceImpl.java:280)
at MyObject.main(MyObject.java:47)
Exception in thread "main"
My first thought was to place the jxpath code inside a try-catch statement.
However by doing this I would be missing out on real exceptions occurring
in the jxpath evaluation. Since all exceptions are re-thrown as a JXPathException
I have no way of differing between a miss and an error. Does anyone have
any ideas as to how to solve this problem?
Many thanks, Agustina
________________________________________ FiberTel, el nombre de la banda ancha http://www.fibertel.com.ar
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