Extend metaclass Association + TemplateBindings

[Dominik K]

Hello,

in our EA project we are using a custom UML profile. This profile contains a stereotype 'X' that extends the metaclass 'Association'.

In our EA plugin we access our EA project to automatically create connectors of stereotype 'X'. E.g.:

Code: [Select]

Connector conn = (Connector) source.Connectors.AddNew("name", "X");
conn.SupplierID = target.ElementID;
conn.Update();

Now, once we attempt to query the template bindings (conn.TemplateBindings; e.g. when iterating through the template bindings in a loop) of the connector of stereotype 'X', we run into a System.Runtime.InteropServices.SEHException ("External component has thrown an exception", ErrorCode: 0x80004005).

Interestingly, if we do the same connector creation but make the connector an "Association" instead of "X", no problem occurs. Furthermore, if we use a file based repository instead of a Database repository, no problem occurs.

Our environment is:

• EA 12.0.214
• Plugin written in C# (.NET Framework 4.5) using the Interop.EA.dll provided by the above mentioned version of EA
• Microsoft SQL Server 2008 SP3

Could there be something wrong with our profile (any special settings required to be able to use template bindings)? Or could it be something with our database? Or should we just file a bug report?

Thanks
Dominik

[qwerty]

I doubt that  AddNew("name", "X") works. To my knowledge you need to AddNew("name", "Association") (or what ever the base connector is) and then assign the stereotype to be "X".

q.

[Dominik K]

Thanks for your reply.
I changed the code to:

Code: [Select]

Connector conn = (Connector) source.Connectors.AddNew("name", "Association");
conn.SupplierID = target.ElementID;
conn.Stereotype = "X";
conn.Update();
Unfortunately, that doesn't solve the issue.

[qwerty]

With this Perl snippet

Code: [Select]

my $e1 = $rep->GetElementByGUID("{250B4CD6-C5CF-4dca-8A9E-7738264637F8}");
my $e2 = $rep->GetElementByGUID("{4260FC5A-29D8-43e3-A60F-1C5DEB4E352B}");
my $con = $e1->Connectors->AddNew("test", "Association");
$con->{Stereotype} = "ConversationLink";
$con->{SupplierID} = $e2->ElementID;
$con->Update();
I was able to create a BPMN ConversationLink. It was just necessary to reload the diagram to see the changes.

q.

[Dominik K]

Hello qwerty,

thanks for the snippet. Could you also try to go one step further and iterate through the (probably empty) TemplateBindings collection of your ConversationLink? Is your repository using a (non-JET) database?

Thanks a lot
Dominik

[qwerty]

I guess it will not make sense to iterate template bindings right after creating a new connector, would it? I'm using Jet3 (IIRC) as default EAP. The code here should however be repository independent.

q.

[Dominik K]

I agree, it doesn't make much sense. However, it reproduces our problem (SEHException) and I would expect that iterating an empy collection should not cause an Exception. Even when we try to iterate through the TemplateBindings collection way after the connector's creation (just to check whether TemplateBindings have been created by some other operation in the meantime) we get the Exception.

I've also reproduced the issue on a MySql 5 DBMS. So, I guess I'll try filing a bug report.

[qwerty]

I ran it without issue (because count is zero). Can you post the snippet where you iterate?

q.

[Dominik K]

Sure, here's the snippet with the pseudo-iteration.
Note however that the problem only occurs if we use a DBMS (Microsoft SQL Server, MySQL) repository. Using a standard file/JET repository works just fine.

Code: [Select]

Connector connector = (Connector)source.Connectors.AddNew("name", "Association");
connector.SupplierID = target.ElementID;
connector.Stereotype = "X";
connector.Update();

// Throws SEHException.
foreach (var binding in connector.TemplateBindings)
{
     // nothing to do really...
}


[qwerty]

I had a similar issue with Perl when not using the right type for the iterator. Have you tried using a for loop with connector.TemplateBindings.count instead?

q.

[Dominik K]

qwerty, thanks for your help so far.
I filed a bug report. Using TemplateBindings.Count does not solve the issue - see the following, small examle application:

Code: [Select]

class Program
{
    // Exemplary connection string.
    private static string ConnectionString =
        "ea_odbc --- DBType=0;Connect=Provider=MSDASQL.1;Persist Security Info=False;User ID=root;Data Source=ea_odbc;Initial Catalog=ea;LazyLoad=1;";

    static void Main(string[] args)
    {
        // Connect to repository.
        Repository repository = new RepositoryClass();
        repository.OpenFile(ConnectionString);

        // Create some test package.
        Package root = (Package)repository.Models.GetAt(0);
        Package testPackage = (Package)root.Packages.AddNew("TestPackage", string.Empty);
        testPackage.Update();
        root.Packages.Refresh();

        // Create two Elements.
        Element source = (Element)testPackage.Elements.AddNew("Source", "Class");
        source.Update();
        Element target = (Element)testPackage.Elements.AddNew("Target", "Class");
        target.Update();
        testPackage.Elements.Refresh();

        // Create and test a regular Association-Connector.
        {
            Connector connector = (Connector)source.Connectors.AddNew("Regular", "Association");
            connector.SupplierID = target.ElementID;
            connector.Update();
            source.Connectors.Refresh();

            Console.WriteLine(connector.TemplateBindings.Count); // Output is: 0
        }

        // Create and test a Connector with custom stereotype 'X'.
        {
            Connector connector = (Connector)source.Connectors.AddNew("Custom", "Association");
            connector.SupplierID = target.ElementID;
            connector.Stereotype = "X";
            connector.Update();
            source.Connectors.Refresh();

            Console.WriteLine(connector.TemplateBindings.Count); // Output is: 1
            if (connector.TemplateBindings.Count > 0)
            {
                // This throws an Exception! Why is there a TemplateBinding at this point and why is
                // an Exception thrown when accessing it?
                TemplateBinding templateBinding = (TemplateBinding)connector.TemplateBindings.GetAt(0);
            }
        }
    }
}


[qwerty]

Really looks like a bug. No idea why you see an element in the collection right after creation.

q.