On 1/7/06, Rahul Akolkar <[EMAIL PROTECTED]> wrote: > > [snip] > * A self transition for a view state should be possible (its > definitely legit in state chart theory, Shale dialogs being state > charts for a specific purpose).
Self-transitions for a view state are definitely legal, but there's an interesting semantic twist here. Since we are in a view state, the transition is based on the logical outcome returned by the action method that is invoked for the submit button that actually submits the form (phew, say that sentence three times real fast :-). If the action method returns an outcome that happens to map to the same view identifier, a *new* component tree is still created, so you lose any state information you've stored in the current component tree. If the action method returns null, on the other hand, there is a short circuit to the normal transition mechanism that causes the current view to be redisplayed, *without* being recreated. This was done deliberately, so that action methods within a dialog work exactly the way they do outside a dialog. From a state chart perspective, you can assume there is an additional unspecified transition that says "if the logical outcome is null, redisplay the current component tree without recreating it." This can be an important consideration when you are designing the UI of your application ... even if the *user* doesn't know or care whether a new view was created or not in this scenario, it can dramatically simplify your dialog configuration, and your application logic, to know that this is a scenario you can rely on. Craig
