This pattern allows multiple Major versions of a native service to coexist in the registry without requiring consumers to change the code in their consumer applications, and helps to ensure a graceful migration to the new Major version.

This is called the “adapter pattern” because Mediator will act as an adapter, adapting the client requests before they are submitted to the native services.

Unlike the Layer of Indirection pattern, which has one virtual service that can access each Minor version of the native service, this pattern has a separate virtual service for each Major version of the native service.

To implement this pattern, you configure the virtual service's Request Processing step so that it transforms the endpoint specified in a request to the endpoint of the desired version. The Request Processing step specifies how the request message is to be transformed before it is submitted to the native service. You can configure this step to perform message transformations using a specified XSLT file or by passing the message to a webMethods IS service (that is, an Integration Server service running on the same Integration Server as webMethods Mediator).