User Interface Service Software Developerís Guide - Hitech Projects

January 2008
Public
interface inputs. They can also retrieve information about a current view that is active in the
user interface. Further, PI-components must implement interface IUIClient in order to receive
information about state changes, changes with respect to the valid value range or to be
informed when a specific piece of information is not shown. Moreover, the IP-components are
informed via this interface what information is to be shown on the screen and which navigation
options the user has.
Interface IUserManagement is used to attach user management components. Form the user
profile the user specific navigation model is retrieved.
Interface IKnowledgeBase is exploited to interface knowledge bases to the system. Via this
interface, new knowledge can be added to the system. This covers adding concepts and
statements. Finally, information can be retrieved from the knowledge base via this interface as
well.
The interface IUIServiceControl can be used to control the behavior of the UI-service. For
example, using this interface, PI-components can be coupled, user can be logged in or out
and statements can be added to the environmental model. If PI-components are coupled, they
behave the same. I.e., the show the same information to the user and also present him or her
with the same navigation options. This may be useful if there are several display in the range
of the user giving him or her the options to freely choose between the them. Moreover, the
user may even change the interaction device on the fly.
3.9.2 Classes of the UI-Service
Figure 6 shows the main classes of the UI-service. Class UIMain implements the singleton
pattern. The appropriate instance is created via the Activator class. UIMain creates further
objects needed by the service. Important classes of the UI-service are:
• Service Manager: The service manager also belongs to the singleton pattern. It is
responsible for administration and communication with services and devices. Services
inform the ServiceManager about state changes using class ServiceActionManager.
• ServiceActionManager: There is also only a single instance of class
SeviceActionManager. The class receives information about changes of internal
variables of services or devices. The instance then determines those PI-components
that are affected by the propagated change und further propagates the information to
other components.
• InternalServiceList: This class is used to manage the registered services.
• UIClientManger: This class implements the interface to register PI-components. For
each registered component this class generates a VirtualUIClient instance which is
used to control the component.
• VirtualUIClient: Instances of the class VirtualUIClient represent PI-components. Hence,
for each PI-component an instance is created to control the component. Class
VirtualUIClient implements IUIConnector which is used for communication with the
associated PI-component.
• UserInputManager: All user input is processed by an instance of UserInputManager. If
the user is operating a navigation element, then the instance informs the corresponding
instances of class VirtualUIClient. Otherwise, if the input changes a value, then the
input is forwarded to the appropriate instance of class ServiceManager.
• UIServiceController: This class can be used to control the behavior of the UI-service.
For example, PI-components can be coupled, user can be logged in or out and
statements can be added to the environmental model.
Amigo IST-2004-004182 103/114