| Re: [ecf-dev] Problem with SharedObject API |
Hello All, Scott, thanks for you reply. It works fine. I had understood SharedObject API and blogged about it http://samolisov.blogspot.com/2009/11/ecf-osgi.html (on Russian). Scott Lewis пишет: > Hi Pavel, > > Samolisov Pavel wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> Thanks Scott. >> >> Tests works fine, my code works too. But I do not understand why this >> code is in TestSharedObject (in method initialize()): >> >> // This is a replica, so initialize the name from property >> name = (String) getConfig().getProperties().get(NAME_PROPERTY); >> >> Is this code a deserialization from Config to SharedObject? Why name do >> not replicate with SharedObject automaticaly? >> > > This code is only executed on the non-primary copy of the shared > object (i.e. the replicas). This code (run only on the primary copy), > is responsible for serializing the state of the shared object (in this > case, it's name): > > protected ReplicaSharedObjectDescription getReplicaDescription(ID > receiver) { > // Put primary state into properties and include in replica > description > final Map properties = new HashMap(); > properties.put(NAME_PROPERTY, name); > return new ReplicaSharedObjectDescription(this.getClass(), > getConfig().getSharedObjectID(), getConfig().getHomeContainerID(), > properties); > } > > And then the code you quote above sets the name (for the replicas) to > the value specified by the properties included in the > ReplicaSharedObjectDescription. The serialization/deserialization of > shared object state is done explicitly rather than implicitly...so as > to give the shared object programmer some control over the > serialization. I was/have been thinking of adding some implicit > serialization of shared object fields (perhaps through annotations > processing or some such), but for the moment everything is explicitly > done (via properties). > >> And another question: Does SharedObject API have any listeners that >> calls when shared object has been added? >> > > Yes, indeed. An IContainerEvent of sub-type > ISharedObjectActivatedEvent is sent to any/all IContainerListeners > before the shared object is activated, and similarly > ISharedObjectDeactivatedEvent is sent before the shared object is > deactivated. The shared object itself is also asynchronously notified > as well (the shared object has a message queue and a thread created > for it to process it's messages...and that's how the initialize method > gets called on the replicas). > > Scott > > -- Pavel Samolisov Meet me at: Vkontakte.ru: http://vkontakte.ru/id3178981 Blog: http://samolisov.blogspot.com Twitter: http://twitter.com/samolisov XMPP/Jabber: samolisov@xxxxxxxxx
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