Test to see if bean is instantiated?

Question

I wanted to test to see if a session scope bean was in fact valid in a beforePageLoad event using SSJS. If I clear the session scopes using the Debug toolbar I get an error when trying to test the bean to see if it is null.

if (registrationBean == null){

The error is: Error while executing JavaScript action expression Script interpreter error, line=2, col=22: [ReferenceError] 'registrationBean' not found

Question is how to test the bean to see if it is instantiated??? If not, then I want to go to another XPage (redirect) to allow the user to enter the values that are used to populate the bean.

Or, is this only an issue because I used the Debug Toolbar to clear ALL session and application scopes?

Howard

Answer 1

Use a try/catch block. If you get the error, it's null.

I suspect it's only a problem because the applicationScope has been cleared. Usually the first attempt to reference the variable instantiates the object. However, clearing the whole of applicationScope can break a lot of XPages code in your application and should be avoided.

Answer 2

First, make sure that the bean is set up in faces_config.xml (but it seems this is the case). Then you should not be able to reference the bean before it is instantiated...

An easy way to see when the bean is instantiated is to put a System.out.println("....") in the constructor of the bean. That should bring you on the track. You could (should!) use the OpenNTF LogReader to see what is going on - this will show you any errors thrown by the page and bean.

And then of course clearing all the data via the debug toolbar may put the system in an "unknown" state - and you should probably try to reload the page subsequently to ensure it is well-defined/-instantiated.

/John