Chapter 3. Examples

3.1. Buyer Seller Protocol
3.2. Credit Check Protocol
3.3. Purchasing Goods Conversation

This chapter presents some examples using the protocol notation.

3.1. Buyer Seller Protocol

This example shows how a Buyer participant and Seller participant may interact in an ordering process.

protocol BuyerSeller {
    role Buyer, Seller;
    
    Order from Buyer to Seller;
    
    choice from Seller to Buyer; {
        Invoice {
        }
        Rejected {
        }
	}
}

3.2. Credit Check Protocol

This example shows how a Client role performs a credit check against a CreditAgency role.

protocol CreditCheck {
    role Client, CreditAgency;
    
    CheckCredit from Client to CreditAgency;
    
    choice from CreditAgency to Client {
        CreditOk {
        }
        NoCredit {
        }
    }
}

3.3. Purchasing Goods Conversation

This example shows how a protocol can be defined that 'implements' the previous two protocol examples.

protocol BuyerSellerCreditCheck {
    role Buyer, Seller, CreditAgency;
    
    Order from Buyer to Seller;
    
    CheckCredit from Seller to CreditAgency;
    
    choice from CreditAgency to Seller {
        CreditOk {
        	Invoice from Seller to Buyer;
        }
        NoCredit {
        	Rejected from Seller to Buyer;
        }
    }
}