Object model

Source: Wikipedia, the free encyclopedia.

In computing, object model has two related but distinct meanings:

  1. The properties of
    formal semantics of programming languages
    .
  2. A collection of objects or classes through which a
    interface to some service or system. Such an interface is said to be the object model of the represented service or system. For example, the Document Object Model (DOM) is a collection of objects that represent a page in a web browser, used by script programs to examine and dynamically change the page. There is a Microsoft Excel object model [1] for controlling Microsoft Excel from another program, and the ASCOM
    Telescope Driver is an object model for controlling an astronomical telescope.

An object model consists of the following important features:

Object reference
Objects can be accessed via object references. To invoke a method in an object, the object reference and method name are given, together with any arguments.
Interfaces
An interface provides a definition of the signature of a set of methods without specifying their implementation. An object will provide a particular interface if its class contains code that implement the method of that interface. An interface also defines types that can be used to declare the type of variables or parameters and
return values
of methods.
Actions
An action in object-oriented programming (OOP) is initiated by an object invoking a method in another object. An invocation can include additional information needed to carry out the method. The receiver executes the appropriate method and then returns control to the invoking object, sometimes supplying a result.
Exceptions
Programs can encounter various errors and unexpected conditions of varying seriousness. During the execution of the method many different problems may be discovered. Exceptions provide a clean way to deal with error conditions without complicating the code. A block of code may be defined to throw an exception whenever particular unexpected conditions or errors arise. This means that control passes to another block of code that catches the exception.

See also

Literature

  • Weisfeld, Matt (2003). The Object-Oriented Thought Process (2nd ed.). Sams. .
  • Fowler, Martin (1996). Analysis Patterns: Reusable Object Models. Addison-Wesley. .
  • Fisher, K.; Honsell, F.; Mitchell, J.C. (1994). "A lambda calculus of objects and method specialization" (PDF). [1993] Proceedings Eighth Annual IEEE Symposium on Logic in Computer Science. Vol. 1. pp. 3–37.
    S2CID 19578302. Archived from the original (PDF) on 2018-07-03. {{cite book}}: |journal= ignored (help
    )
  • Marini, Joe (2002). Document Object Model: Processing Structured Documents. Osborne/McGray-Hill. .
  • .

External links