HOPEX IT Architecture V2 > Architecture Specification > Describing information exchanges > Describing Exchange Contracts > Creating Exchange Contracts
Creating Exchange Contracts
You can create an exchange contract:
• from a library,
• from a diagram offering interaction creation, for example.
Whatever the point of origin, you can create an exchange contract in standard mode or using an exchange contract template.
*For more details on exchange contract templates, see Using an exchange contract template.
Creating an exchange contract in standard mode from a diagram 
To create an exchange contract in standard mode, in a diagram, from an interaction:
1. In the diagram insert toolbar, click the Interaction button.
2. Draw a link between the two communication entities.
3. In the add composite conversation dialog box, click the arrow at the right of the Exchange Contract box and select Create Exchange Contract.
The Creation of Exchange Contract dialog box opens.
4. Select the Creation Mode: Standard Creation.
*For more details on exchange contract template use, see Creating an exchange contract from an exchange contract template.
5. Enter the name of the exchange contract in the Name box.
6. Click OK.
7. In the interaction creation dialog box, enter the name of the interaction using the name of the exchange contract and click Add.
The interaction and exchange contract are created.
Creating an Exchange Contract Diagram (BPMN)
Creating an exchange contract diagram (BPMN) 
An exchange contract is represented by an Exchange Contract Diagram (BPMN).
To create an Exchange Contract Diagram (BPMN) from an interaction:
1. Right-click the interaction.
2. Select the associated exchange contract and, in its pop-up menu, click New > Diagram
3. In the dialog box, select Exchange contract diagram (BPMN).
The diagram opens with the exchange contract frame and the two roles representing consumer and the supplier.
*A role is a participant in an interaction, workflow or process. It can be the initiator, that is the requester of a service, or it can represent a sub-contractor carrying out processing outside the service. A role is an integral part of the object that it describes, and is not reusable. It can subsequently be assigned to an org-unit internal or external to the organization or to an IT component. Examples: client, traveler.
The events, gateways and sequence flows of your diagram follow the BPMN standard.
*For more details on events, gateways and sequence flows, see Managing events, gateways and sequence flows
Defining an Exchange or an Exchange Contract Use 
In an Exchange Contract Diagram (BPMN), operations are described by:
• exchange contract use
• exchange use
*An exchange contract use is associated with an exchange contract. It enables representation of complex exchanges.
*An exchange use represents the usage of an exchange in another exchange contract.
To create an exchange contract use:
1. Click the Exchange Contract Use button and click in the diagram within the exchange contract frame.
The creation dialog box opens.
2. Click the arrow to the right of the Specification of an Exchange Contract Use box.
3. Select Connect Exchange Contract from the drop-down list and choose the exchange contract that you want to use.
4. In the From field, select the described exchange contract role connected to the "Consumer" role of the exchange contract use.
5. In the To field, select the described exchange contract role connected to the Supplier role of the exchange contract used.
6. Click Finish.
*The Exchanges property page provides access to the list of components of the exchange contract.