Service payment

There are various models for service payment, and various possibilities for implementing them in Jtrix:

• Pay as you go.

  When a service is bound, a standardised facet is used to transfer a wallet warrant from the client to the server. The standard facet would be implemented by the client and requested by the server.

• Pay on contract negotiation.

  A fixed fee is charged. This is paid at contract negotiation time (possibly offline) and time-limited warrants issued for the service. Payment is not required when the service is used.

• Account based payment.

  When the contracts are negotiated, an account is set up. The service issues an extra warrant to allow the account to be inspected or maintained. Payment is not required when the service is used.

• Controllers and users.

  Two kinds of warrant are issued, one for simple users, and one for controllers. Users do not pay, but their operations are reflected to controllers for authorisation and payment collection.

• Service-specific currency

  A service can be paid for using a soft currency mechanism which is managed separately. This could be used by an application to control the usage of the resources for which it is paying by controlling the distribution of this currency.

The possibilities are open, within the constraints imposed by the Wallet model and patterns of use supported by the various parties. Such patterns are built into the interfaces for the services involved. Implementation of these patterns should be factored out from the Service interfaces, so that implementation may be delegated to standard (and extensible) support code.