The object model has got two distinct meanings which are related in the field of computer science:
1. The Properties of the Objects:
– It is under the context of the specific programming language, methodology, notation and technology which makes use of them. The below mentioned examples will help you understand this meaning better:
– The java objects model
– The COM object model
– The OMT object model etc.
– The above mentioned types of the object models can be defined using the concepts such as the following:
– Generic function
– Polymorphism and
– Formalized object models are considered to be the subsets of the formal semantics belonging to the programming languages.
2. A Collection of Objects and Classes:
– Through this collection, a software program can be examined and its specific parts can be manipulated.
– It is like the object – oriented interface for some system or service.
– This interface is commonly known as the object model of the software system or service that is represented.
– An example will make this clear:
The document object model or DOM consists of the objects that can be used for the representation of a web browser page that is used by the script programs for examining the page and then changing it dynamically.
Another example is of the Microsoft excel object model which is employed to keep a control on the Microsoft excel via some other program.
Another example is given by the ASCOM telescope driver object model that is used to keep a control over the astronomical telescope.
Features of Object Model
An object model is characterized by its certain features which have been discussed below:
1. Object Reference:
– These can be used to access the objects.
– It is required to give the method name as well the object reference name in order to invoke an object method.
– These are to be given along with the arguments.
– An interface is actually used for defining the signature of the sets of methods without having to specify the implementations.
– A particular interface is provided by an object if in case its class constitutes of the code that is used for the implementation of the method corresponding to that particular interface.
– Also, the types of declarations of the parameters, variables or return values of the methods are defined by the interface.
– Whenever a method is invoked by an object in some other project leads to the initiation of an action in an object oriented programming.
– It is possible for such an invocation to include additional info that might be needed to implement the particular method.
– The appropriate method is then executed by the receiver and the controls are then returned to the object that invoked.
– In some cases the result might be supplied along with the controls.
– It is quite probable that the software might encounter various unexpected conditions as well as the errors having various levels of seriousness attached to them.
– Thus many different problems are discovered during the execution of the method.
– A clean way to deal with such conditions and errors is provided by the exceptions without adding to the complexity of the code.
– For throwing an exception it is required to define a block of code every time an unexpected condition is encountered.
– Actually, the control is passed to another block of code by which the exception is caught.
Object technology is becoming a popular means for the representation of the structured sh-arable information. A number of different object models are available which may be instantiated in languages that represent data such as the EXPRESS and are then translated in to the OMG IDL.