Hi, Some comments. I'm sure I'll have more once I've had a chance to catch up.
Alasdair On 1 April 2010 00:42, Guillaume Nodet <[email protected]> wrote: > Renaming the subject of this thread. > >>> 5. Subsystem.getState(). I wonder if we should reinvent here. Is >>> there any reason why we don't make the return type of int, and just >>> delegate this to the compositeBundle.getState(). Also, what if the >>> composite bundle and constituents have different states. Does this >>> method only work when the states are consistent among these bundles? >>> >> >> My original idea was also to map closely to the composite state, so I don't >> have any problem >> using an int instead of an enum, though I think the state of composite is >> an int because a composite >> *is* a bundle and enums did not exist at the time the bundle interface has >> been created. >> However, Subsystem do not inherit the Bundle or CompositeBundle interface, >> so we could decide to >> use an enum (because the state is semantically an enum). I think we should stick with an enum. If the Bundle API had had enum's available when it was originally written it would have used enums. Let's not stick in the past. >> >> That being said, the question you raise about the constituents state is >> important. We need to choose >> whether we want to represent the state of the subsystem as an aggregate of >> the constituents state or not. >> That would surely be interesting, because you would know the real state of >> your subsystem much more >> easily. The problem is i'm not sure what would happen if one of the >> bundle can't start or is manually >> stopped by the user. Would this leave the subsystem in the STARTING state >> until the start or stop >> method is called ? >> I do not see how it can represent the aggregate state. If we have 10 bundles in a subsystem where half are started and half stopped what would the aggregate state be? In fact is this even a problem? Perhaps this is the normal state. I think that the first thing to decide is what does it mean to start and stop a subsystem. Once we know what that means we can decide if a relationship with the bundles in a subsystem makes sense. >> >>> 6. Subsystem.start() or stop(), I think it should throw either >>> BundleException or SubsystemException. >>> >> >> Yeah, SubsystemException would be fine. Currently I've defined >> SubsystemException as being >> a RuntimeException though ... >> I suspect this might be a dangerous question to ask, but why a RuntimeException :)? >>> >>> 7. The return type of Subsystem.getHeaders, do we want to use >>> Dictionary<String, String> or Dictionary to be consistent with >>> Bundle.getHeaders()? when we implement this method, we can just >>> delegate to compositeBundle.getHeaders. >>> >> >> Two things here. First, I'm not sure we would want to return the composite >> headers. >> First because composite headers can't be localized, and second because i >> was thinking >> about returning the headers from the subsystem manifest as it was >> installed, not of the >> underlying composite (which includes computed headers for package and >> service policies). >> So if we return directly the composite headers, it would surely make more >> sense to use the >> same type, but if we don't, i think using Map is more natural. OSGi is >> really the only place >> that uses Dictionary instead of Map ;-) >> I would use Map. If Map had existed when the OSGi interfaces were first created it would have been used. I think we should stick with Map. >>> >>> On Mon, Mar 29, 2010 at 6:34 PM, Guillaume Nodet <[email protected]> >>> wrote: >>> > FWIW, I've slightly updated the API with some feedback here and mostly >>> two >>> > other changes: >>> > * moved some management methods from Subsystem to SubsystemAdmin >>> (update >>> > and uninstall) >>> > * make SubsystemConstants a non instantiable class instead of an >>> interface >>> > Why move away from an interface? -- Alasdair Nottingham [email protected]
