1.2 class application

An application object defines a collection of cooperating frame objects. Applications are new as of XPCE version 4.9, and therefore do not yet have a stable definition. It is however assumed that the current implementation will only be enhanced with new, compatible, features.

Applications are designed to deal with the following issues:

• Find frames belonging to the application Using the application<-member method, frames that constitute an application can find each other. See also frame<->name and graphical<-application.
• Define the scope of modal frames Frames may be defined modal over the other frames in the application. See frame->modal.
• Define general application properties XPCE itself uses applications of application<-kind: service to realise the programming environment, and avoid the environment from tracing and debugging itself.

  Normally, applications are created explicitely, often as global named objects. Frames are attached to it using the application initialisation argument application:

  :- pce_global(@my_application, make_my_application).
  
  make_my_application(App) :-
          new(App, application(mine)),
          ...
  
          ...
          new(F, frame('My title',
                                   application := @my_application)),
          ...
  

1.2.1 Instance variables

application <-> kind: {user,service}

If user, (default), the methods and predicates called as a result of event-handling by windows and frames of the application can be debugged. If service, all Prolog and XPCE activity will be run in system mode to avoid debugging the XPCE environments tools, while trying to debug the user application.

Timer objects are not covered by this flag as they do not belong to an application. They provide the timer->service method to turn them into a service.

application <- members: chain

Chain holding member frames. This chain is maintained by application->delete and application->append.

application-modal: chain

Frame that currently acts as modal window for the application. This implies that no window in another frame object can receive events. See also frame->modal.

application <-> name: name

Identifier name of the application. Currently not used.

1.2.2 Send methods

application ->append: frame

Add frame to the application. See also frame->application, and the application argument of frame->initialise.

application ->delete: frame

Remove frame from the application. Associating a frame with another application object will automatically delete it from the application it was a application<-member of. This method may be redefined to keep track of the applications, but must call the super-implementation.

application ->initialise: name

Create an application with the given name. The application is added to the chain object @applications.

application ->reset:

Implementation of visual<-reset. Removes any possible application<-modal frame object.

application ->unlink:

Destroying an application will invoke visual->destroy on all application<-members.

1.2.3 Get methods

application <-contains: -> chain

Implementation of visual<-contains, returning application<-members.

application <-member: name -> frame

Find a member frame object with given frame<-name.