Olaf is spot on! On Sun, 3 Nov 2002 02:57, Olaf Bergner wrote: > Vjeran Marcinko wrote: > >Hi folks. > >I'm embarassed how much simple question I have to ask lately, but since > > there's no much of documentation, I don't see any other way... > > >Can you answer me shortly - Does every component that is capable of > > generating asynchronous events (let's say to all of it's registered > listeners) is > > >violating IOC concept since then control flows from said component to any > > registered listener, and not only to it's child component? > > >Example is excalibur's resource monitor component that notifies listeners > > when resource gets changed .... > > My answer would be no. I think we have to separate two concepts: flow of > *control* and flow of *information*. Well, we could get philosophical about > whether on a very fundamental basis control and information are indeed > equivalent but that's not the point. Nearly every component passes > information to its parent component, be it only in the form of a return > value of a method called on this component. But the *interpretation* and > *usage* of this information is entirely up to the parent component. So is > the interpretation and usage of those change events passed to it by > Excalibur's resource monitor component. > > On the other hand, if a parent component decides to equip a child component > during contextualization/configuration with a certain fixed set of > resources, be it other components, database connections etc, this child > component has no choice but to operate within the confines determined by > these resources. Thus *control* flows from parent to child, which is a good > thing. A child would violate the IOC if it were to call, say, a > hypothetical setDatabaseConnection(Connection conn) method on its parent > component, thus altering its set of resources/configuration options. No > decent, god-fearing child will ever do that to its mother! > > Well, that's my view. Hope it helps, > > Regards, > Olaf Bergner
-- Cheers, Peter Donald ----------------------------------------------------------------------- | I thought there was a knob on the TV to turn up the intelligence. | | There's a knob called "brightness", but it doesn't work. | ----------------------------------------------------------------------- -- To unsubscribe, e-mail: <mailto:avalon-users-unsubscribe@;jakarta.apache.org> For additional commands, e-mail: <mailto:avalon-users-help@;jakarta.apache.org>
