Corona CC Model Changes

First of all I think we need to define use cases and see if we can support it with current model.

ContextContainer

Dennis O'Flynn

The ContextContainer (and ProjectContainer) classes are generated from an EMF model. Additional methods need to be added to these classes as well as updating the functionality provided by some of the generated methods.

• Modify our usage of EMF to generate the model from annotations from the ContextContainer interface instead of schema
• Create a JET template to use by EMF/SDO code generation to merge new functionality as well as update existing methods
• ContextContainer.postEvent()
  • Estabalish the only way to post a container event is by using the container's postEvent() method.
  • Refactor non-container event posting mechanisms as internal.
  • Annotate the postEvent() for WS-Notification
• ContextContainer.addEventHandler()
  • Estabalish the only way to add a container event listener is by using the container's addEventHandler() method.
  • Refactor non-container event handler mechanisms as internal.
• ContextContainer add/update/delete methods
  • embed within each add/update/delete methods an invocation of postEvent() to notify the collaboration environment that the container has been modified.
• Common ProjectContainer functionality
  • Refactory ProjectContainer to move any non-Project specific functionality to the ContextContainer

Project Context Container

Pawel Kaczmarek

Merge PCC and CC. There are VERY few operations that are specific to ProjectContextContainer. The separation of the two causes many unnecessary packages and classes to be created and maintained. The idea behind CC and PCC was to support extensibility, however, the classes are so highly integrated within Corona that it is doubtful if anyone will want subclass CC or PCC.

Probably it will be faster to leave PCC and merge CC into it.

I think it is good idea. There is a proposal how to move PC Manger to generic CC Manager -- Marcin Okraszewski

Not a good idea. -- Dennis O'Flynn

• The ContextContainer is part of the collaboration framework.
• The ProjectContextContainer is part of the exemplary implementation
• If the two are merged, how would we show an example of how to build a collaboration solution?

Content-format attribute in repository - bug 168680

Marcin Okraszewski

All details in the bug.

Rename URI attribute to ID

Marcin Okraszewski

The name of URI attribute is misleading. Its primary function is ID. It is intended to keep URI form to keep uniqueness and be easily used in external RDF. But the URI suggests that it carries some kind of connection information, which it doesn't.

I agree that this can be misleading. -- Dennis O'Flynn

• If it (URI) is an ID, call it an ID.
• If it is an URI, than return a URI

Resource id for content adapter

Marcin Okraszewski

We intend to make a layered architecture there there is repository adapter and content adapter. The content adapter would parse resource returned by repository adapter. So, the content adapter needs to know the argument to call fetchResource() with.

Eg. We have a team member XML file in CVS. Repository adapter is used to connect CVS. Content adapter is used to parse the file. But how the content adapter know which file to choose?

Should it be some predefined repository connection?

Repositories as an external entity ; repository events ??

Marcin Okraszewski

Comes from a pretty simple use case. We have a repository which is added to two containers (A and B). Now someone changes state of the repository (eg. removes a resource), but in container A. The event is sent in container A. An other user that works with container B is not aware of the change !!!!!

This leads to a point that maybe repositories should be detached from CC. CC would contain only a reference to a repository. That would mean that either we would have to provide also repository events or propagate the event in all CC that refers to repository.

Tree structure of containers (subcontainers) - repository inheritance

Marcin Okraszewski

At the very beginning we had an approach that containers would be organized in tree structure. Then we have changed it into "related containers". Why don't we have both?

Why? Look into definition of containers for Corona project. There are a number of containers: Corona, Corona Development, Corona Client, Corona Server... Each of the containers need to contain a team member repository, which is the same for all of them. Eg. Bugzilla is similar case.

If we had a tree structure of containers and provide a new flag in repository ("inherit"), we could solve it. Note that the system container is intended to contain other repositories, so the mechanism of sub containers need to be available anyway. In this way for instance we could define a default event router for all containers at a single server.

Rename "repository" ?

Marcin Okraszewski

The repository element is used not only for describing repositories. It keeps web service descriptions, event router settings, etc. This was pointed and suggested at other page connected with API changes: Corona CC New Approach.

For now seems like repository element is used to keep information about anything that is connectible. Maybe it should be named connectibleElement?

Any suggestions on the new name?

Reference between repositories

Marcin Okraszewski

Described in details in stackable repositories section at an other page.

Free form part in repository descriptor

Marcin Okraszewski

In general property-value model not always is enough. Maybe it would possible to have added a "free form" xml element in each element. A repository adapter of a given type would know how to use it then. Obviously usage of this element wouldn't be required.

Don't know if it is possible with EMF generated model ... I'm afraid not. For sure it is possible in XML Schema. Repository adapter could access those information for instance in a DOM form.

For instance if we would like to have repository that invokes a command through SSH, but the command requires some parameters. We could have it like this (element intentionally simplified):

<repository content-type="build">
  <connection access-type="ssh" content-format="command">
    <property name="host">corona.eclipse.org</property>
    <property name="cmd">cd /home/releng ; buildAll.sh {$buildType}</property>
    <extension>
      <user-input name="buildType" label="Please select build type" type="combo" >
        <item value="M">Maintenance</item>
        <item value="N">Nightly</item>
        <item value="I">Integration</item>
        <item value="S">Stable</item>
      </user-input>
    </extension>
</repository>

Without <extension> element it would be very difficult to write and use.

CC as RDF ... I'm dreaming

Marcin Okraszewski

I still believe that keeping CC in RDF would be a good idea:

• everything is done by references
• RDF Schema could provide a default model which could be extended by anyone without influencing the default model; I can make a bet that our model with repositories descriptor and properties within it finally won't work for some case ...
• you can also generate class representation from RDF Schema that isolates you from RDF RDF Reactor
• allows to integrate with DOAP (Description of a Project) - RDF vocabulary to describe open source projects
• easy integration with any SemanticWeb data sources, eg. FOAF
• RDF is future! Almost no scientific project is funded by EU unless it is connected with SemanticWeb
• RDF is about information integration (sounds strange, I know)
• extensibility, extensibility, extensibility ...