Wednesday, 4 November 2009

Week 44 of 2009

Last week I mentioned that I would provide a few screenshots of the new relationship identification scheme in OOA Tool. The first shows the Information Model subsystem from the OOA Tool Model which uses Shlaer-Mellor notation:

You can see that relationship IDs are still used as before but users can now search for relationships by a primary object followed by a verb phrase following by an optional secondary object. This is much easier and is more natural when tracking down a navigation in some Action Language code which no longer has to reference relationship IDs. There is still a minor issue here concerning which object is selected as the primary object in this scheme. I have chosen the first object for simple, composed and mathematically dependent relationships, the associative object for associative relationships and the supertype object for subtype-supertype relationships. Obviously, searching for details of a navigation from a secondary object is still more difficult at present. However, all navigations should involve the primary object, e.g. all subtype-supertype navigations involve the supertype object. The only partial exception is that a user could navigate across an associative relationship without explicitly referencing the associative object since the Shlaer-Mellor virtual machine can handle any navigation thru the associative object automatically.

For simple relationships, the initial choice of first object is often arbitrary and has been of little concern in the past. However, users may now want to select the most apprioriate primary object as their first object when creating simple relationships, e.g. in the relationship INFORMATION MODEL defines OBJECT, the INFORMATION MODEL object is definitely the most appriopriate primary object and thus should be first. Users can still swap first and second participants around later if they want to change their mind.

The second screenshot shows the Elevator PIM from the Starr01 Elevator Model which uses Executable UML notation:

You can see that relationship IDs are still used but are shown in the property list associated with each relationship.

I'll keep this week's report brief otherwise next week's report will be even briefer since I'm eating into next week's available time! However, I will mention that I revisited the Naming service domain used in the OOA Tool Model and the Naming technical note that was previously blogged. I've significantly revised the model and have resolved how the Naming service can be bridged to the OOA of OOA domain where names are used. However, I will leave the details until later since I plan on republishing the technical note. The new technical note also includes a Java Applet allowing name parsing and formatting to be demonstrated!

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