The image shows the relationships among the BPEL components, including:
BPEL Engine: Business Process and TaskActionHandlerProcess (Manages task life cycle)
Worklist application: Web application to search for tasks, view tasks, act on tasks
Workflow Services
Identity Service Provides: User/group/role lookup, user authentication, authorization
Task Manager and Task Routing Service: Provides task persistence, task escalation/reassignment based on user info, APIs to retrieve tasks based on specified criteria, role resolution, send notifications.
Worklist Service: Retrieve tasks based on specified filter, sort tasks, retrieve task attachments, and perform action on selected tasks
Notification Service: Sends notification to users by e-mail, voice message, or short message service
User Directories, which can be Oracle Internet Directory, JAZN/XML, or LDAP, Custom