two connections between the same input and output connectors

[alexey-schroeder]

it is possible to create two connections between the same input and output connectors. the connections can not be distinguished

[miho]

That's true. The default model does allow multiple connections. But it can be disabled by defining a custom connection rule. Basically you pass a custom ValueObject to the connector.

Have a look at DefaultConnectorValueObject.java to see how this can be done.

If you'd like to contribute other rules (one-connection only etc.) you can open a pull request.

[aalmiray]

Is the ValueObject the right place to do this kind of check?