Overriding other plugin's decisions

Well, basically the "cancelled state" can be removed by calling setCancelled(false);. But that depends on when the event listener is executed exactly (or more precisely, in which order the plugins are executed). Example: You have three plugins and they're actually called in this order (plugin 1, plugin 2, plugin 3). By default, the "cancelled" state is set to false. Now if plugin 1 cancels the event, plugin 2 and 3 can see that (by calling isCancelled()), so they can either ignore it (so the event will be cancelled), or set the cancel state to false (then the event will be executed). But if plugin 1 cancels the event, plugin 2 explicitly sets the cancelled state to false and plugin 3 cancels the event again, the event will be cancelled.

Hmmm... this seems to me hard to tell. Scenario:

• Both plug-in A and plug-in B hooks the SomekindofEvent.
• According to A, one of these events should be cancelled, but according to B it should not.

I see at least two fuzzy points:

• If A cancels it (event.setCancelled(true)) and, afterwards, B un-cancels it (event.setCancelled(false)), who wins? the last one?
• There is no way to be sure that A gets the event before B or of any notification order in general.

From one point of view, one could say that plug-in A is not the right solution for the task and it should be modified (which might be possible or not).

From another point of view, this might be a much more general problem and an actual "protocol" should be devised for plug-ins to speak to each other. Still, in general, it might be impossible to tell which of not just two, but n plug-ins dealing with the same matter is right.

EDIT: oh well, red51 beat me by 5 min!