How to extend multiple classes in Hyperledger composer .cto file

Question

I want to create a new Role extending two existing roles. So is it possible in composer modelling language for a participant to extend multiple participants?

Answer 1

It is not likely to be supported as multiple inheritance is tricky and you would be forced into design issues in Object Oriented systems - Diamond Problem in multiple inheritance .

Answer 2

A Participant Type can only Extend one Participant type.

Using Concepts may allow you "re-use" elements of the model and ensure consistency.

concept Manager {
  o String MTitle
  o String QualificationType
}

concept Engineer {
  o String ETitle
  o String CharterCertType
}

participant Mgr identified by mID {
  o String mID
  o String name
  o Manager manager
}

participant Engr identified by eID {
  o String eID
  o String name
  o Engineer engineer
}

participant EMgr identified by emID {
  o String emID
  o String name
  o Manager manager
  o Engineer engineer
}

The modelling language is covered in Modelling Language and Model Compatibility