Question

Currently my code is like

<h:panelGroup rendered="#{templatePrescriptionMaintenanceBackingBean.allSelectedMedicationList != null && !empty templatePrescriptionMaintenanceBackingBean.allSelectedMedicationList}">
        <b>List of Selected Drugs</b> // and some other stuff
</h:panelGroup> 

Now allSelectedMedicationList will do lot of process in backend. Calling webservice and adding data in current DB and so on…

Now issue arise when I need to check null or empty – 2 times that method called here. Once again when I use same method with datatable it will call again 1 more time.
I think to create one method or something for JSF it self that will check null and empty at same time and return list. Is it possible?

Answer 1

The operator “empty” already does what you want, you don’t need to also check null.

From http://docs.oracle.com/javaee/5/tutorial/doc/bnahq.html#bnaik:

Empty: The empty operator is a prefix operation that can be used to determine whether a value is null or empty.