How to call an info engine task from a workflow expression in Windchill PDMLink

Sample Code snippet is given below:  if(primaryBusinessObject != null && primaryBusinessObject instanceof wt.doc.WTDocument){   com.infoengine.SAK.Task task = new com.infoengine.SAK.Task("examples/queryForObject.xml"); // RELATIVE PATH OF THE INFO ENGINE TASK XML  task.addParam("type","wt.doc.WTDocument"); task.addParam("number",((wt.doc.WTDocument)primaryBusinessObject).getNumber()); task.invoke();   com.infoengine.object.factory.Group group = task.getGroup("result"); String name = new String((String)group.getAttributeValue(0,"name"));   }