Architecture of the Windows Workflow Foundation.
The basic architecture of Windows Workflow Foundation is comprised of the following layers.
* The Hosting Layer
* The Runtime Layer
* The Workflow Model Layer
Hosting Layer:
The Hosting Layer is one that provides pluggable interfaces between Windows Workflow and a specific host.Windows workflow foundation is an in-process engine that runs inside a host process.The host process is responsible for providing a set of services to WF. some of the host processes are console application, web, winforms ,webservices,share point applications.
The main thing is any executable process can host the WF runtime engine.The basic services provided by this layer include the following.
· Persistence services
· Thread support
· Communication Support
· Timer services
Runtime Layer:
The Runtime Layer is a non-pluggable layer as is the core of the WF architecture and is responsible for Workflow management and Workflow Execution. The basic services provided by this layer include the following.
· Workflow Execution
· Workflow State Management
· Workflow Activity Scheduling
· Rules and Policy Management
Model Layer:
The Workflow Model Layer provides the API for working with Windows Workflow Foundation in .NET framework. Basically, the Workflow Model Layer defines two models.
· The Sequential Workflow Model
· The State Machine Workflow Model
