Operation contexts

Each operation has a context that contains the operation data. This data includes data from input fields in an operation view and data from an external source such as a host or local database. Because the operation context is part of the context hierarchy, the operation can access data at the different levels in the context chain. The context may also include services. When an operation wants to execute a service, it uses a service alias to get a reference to the service. If there is more than one service in the chain of contexts with the same alias, the toolkit returns the first service it finds in the chain. It starts the search in the operation context and proceeds through the context chain until it finds the service or completes searching the root context.

The link between an operation and its context can be statically set using a definition in an XML file or dynamically using the operation interface protocol. The context is statically chained to its parent in the context hierarchy using the operation's definition in an operation XML file or dynamically using the context interface protocol. Usually, the toolkit chains client operation contexts statically using definitions while the C/S Messaging API chains server operation contexts dynamically when launching an operation requested by the client side.