Gang - One of our unit tests here at Oracle tripped up over a small change in behavior between JSF 1.2 and JSF 2. The unit test contains an action method that returns an empty string, eg: <h:commandButton action="#{foo.doSomething}"/> public String doSomthing() { // Do something here return ""; } When running against JSF 1.2, the empty string outcome would result in the test case remaining on the same page, as there is no navigation case that matches this outcome. In JSF2, implicit navigation kicks in. In particular, the following statement from section 7.4.2 is applied: > If viewIdToTest does not begin with “/”, take the current viewId and > look for the last “/”. If not found, prepend a “/” and continue. > Otherwise remove all characters in viewId after, but not including, > “/”, then append viewIdToTest and let the result be viewIdToTest. In our case, we have the following values: - Current viewId: "region/refresh". - viewIdToTest: "" The resulting view id after applying the above logic is "region/". This ends up being treated as an implicit view id. In our particular test case, there is no view associated with this view id. Instead of remaining on the same page, we now attempt to navigate to a view that does not exist. Our test case made the assumption that returning the empty string from the outcome would result in the same behavior as returning null. This was true in JSF 1.2, but no longer appears to be true in JSF2. We have tweaked this unit test to return null so that our tests are now passing, but I wanted to follow up to find out whether this small difference in behavior between "" and null outcomes is intentional. It seems to me that these should behave the same. It would be easy enough for us to add a sentence to the spec that states that empty string outcomes should not be treated as implicit view ids. Does anyone here know of a reason why we shouldn't spec this? FWIW, my feeling is that, while returning null is a reasonable workaround, there is no way that our unit test is not the only code out there that is returning empty action outcomes and expecting to stay on the same page. I would like to see this behavior preserved not so that we can revert our unit test to its previous behavior (I am fine with our fix), but because the current behavior may break other users as they upgrade to JSF2. Thoughts? Andy

On 2/15/10 3:49 PM, Andy Schwartz wrote: > FWIW, my feeling is that, while returning null is a reasonable workaround, > there is no way that our unit test is not the only code out there that is > returning empty action outcomes and expecting to stay on the same page. I > would like to see this behavior preserved not so that we can revert our unit > test to its previous behavior (I am fine with our fix), but because the > current behavior may break other users as they upgrade to JSF2. > > Thoughts? > I know in the apps I've worked on whether I return an empty String or null depends on the mood I'm in. :) I think we should clarify the spec to preserve the 1.2 behavior. -- Jason Lee, SCJP President, Oklahoma City Java Users Group Senior Java Developer, Sun Microsystems http://blogs.steeplesoft.com