The "Invoking Applications Interface" defines an interface mechanism between Workflow Management Systems and any other application, but it, however, differentiates itself from the other Coalition interface definitions. Invoking an application is not a workflow specific functionality, but a Workflow System would not make much sense without this functionality.
Therefore, this interface addresses workflow system vendors as well as any third party software vendor. Based on different communication technologies the so-called "Tool Agents" can handle the application control and information exchange. These Tool Agents represent at least one specific invocation technology. E.g. while one Tool Agent supports DDE commands, others can communicate based on protocols like OLE or CORBA or any other concept.
The technology to interact between a Tool Agent and a corresponding application depends on the underlying architecture and on application - specific interfaces, which have to be managed under control of the Tool Agent itself. The suggested interface defines the way a Tool Agent can be used by a workflow application, e.g. a worklist handler or the workflow engine. Finally, the purpose of Tool Agents can be compared with the purpose of standardized software components.
The set of application interface functions provides services to Tool-Agents, to invoke and control applications associated with specific work items.
The Invoked Application Interface defines an API set, which is highly recommended to be used by Workflow System components (engine and client applications) to control specialized application drivers called Tool Agents. These Tool Agents finally start up and stop applications, pass workflow and application relevant information to and from the application and control the application's run level status. Therefore, the Invoked Application Interface WAPIs are only directed against a Tool Agent. Nevertheless, additional workflow information could be requested by an application via the Tool Agent using standard WAPI functions. As the Invoked Application Interface should handle bi-directional requests (requests to and from applications), it depends on the interfaces and architecture of applications how to interact with an Tool Agent.
This interface will allow the request and update of application data and more run-time relevant functionalities.
The Workflow System itself has to know about the installed Tool Agents. The basic architecture of Tool Agents could be compared with a driver - interface, i.e. ODBC, etc.. Within this interface definition, no further communication mechanism between the Tool Agents and the Workflow System is necessary.