" Secondly, a model M will in general have properties that O does not have and that actually aid I in investigating M. What the investigator I does in modeling is formulating a problem P in terms of the original O, translate that problem into a problem P' in terms of M, obtain a solution S' of P' and translate S' into a solution candidate S of P in terms of O . If S is actually a solution of P then the modeling process was successful and can be terminated. If, however, that is not the case then the investigator I can start over with a different problem, model, means of investigation, or relation between model and original. It is worth noting that the concept of solution to a problem depends on the investigator, its purpose, intended means of investigation, time-horizon of that investigation and so forth. What has been presented here so far essentially is due to Stachowiak, [1]. To understand how then models are used in more detail one needs to distinguish from each other the various reference modes in which the investigator puts the model with respect to the original. Daughter Model Mother Russian The reference modes that perhaps are most important in computing are: (1) descriptive, i. e. "

" MVC models allow the code to be more flexible later in the development process, allowing for changes that make sense at the time it makes sense to make them. Event driven In contrast, objects in object oriented programming are composed of methods and data members that attempt to model something from the domain of interest. The best models are fully encapsulated, meaning that they implement every aspect of that real world object of interest to the domain of interest, and that they don't have any extra code that doesn't model the real world. Encapsulation also means that the class is implemented in such a way that the internal representation of data is not exposed to the user of the object. The impedance mismatch between these two worlds, that of events, and that of objects, is something that's been recognized for a long time. Getting these two worlds to cooperate requires a lot of 'glue code' to make them work together. The 'model-view-controller' paradigm introduces the controller object in between the view (the GUI class) and the model (the object) to communicate between the other two objects. Russian Child Fashion Model The actual implementation of the controller object can vary quite a bit, but the idea of an object to 'transform' events to changes in data and execution of methods is the essence of this pattern. What does "event driven" mean? Was there ever an application which did not respond to user events. "