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 {
    participant Buyer, Seller;
    
    Order from Buyer to Seller;
    
    choice from Seller to Buyer; {
        when Invoice {
        }
        when Rejected {
        }
	}
}

3.2. Credit Check Protocol

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

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

3.3. Purchasing Goods Conversation

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

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