Bug 456352

Description Pierre-Charles David 2014-12-30 10:07:49 EST

Currently Sirius supports a mode where several different Sessions share the same TransactionalEditingDomain and ResourceSet (this is triggered by setting DAnalysisSessionImpl.setDisposeEditingDomainOnClose(false)).

Supporting this means we can not simply consider all resources in the ResourceSet which are neither aird not VSMs to be semantic resources of the session. Instead we have to keep track of which resource is actually associated to this session (and not to another one sharing the editing domain). The maintenance of the corresponding DAnalysis.models reference is very costly compared to the alternative (the alternative being: "if its is not the main aird, an aird referenced by it, or a VSM referenced by an aird, it is a semantic resource").

The "shared editing mode" is relatively marginal and a somewhat hidden feature. The only client who actually used to use has siwtched to the "normal" mode, so it is time to remove support for it and leverage all the optimizations which become possible once this is done.

If possible at a reasonable cost, the "shared editing mode" should still be available as a deprecated mode in at least one major version of Sirius (e.g. 3.0), before we completely remove all the corresponding code from the codebase in the next version (e.g. 4.0).

Steps:
1. Devise a plan to keep the old session code as it is if possible, maybe under a different package, so that the "legacy" mode can still be used if really needed in Sirius 3.0, but we still can cleanup the main/default session implementation of all traces of it.
2. Simply remove direct support for setDisposeEditingDomainOnClose(false), and make sure everything keeps working fine (especially the tests).
3. Gradually replace all the costly mechanisms which were only needed to support this mode with simpler and more efficient ones. This may require the creation of sub-tickets for individual tasks.