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Association (object-oriented programming)
Encyclopedia
In object-oriented programming
, association defines a relationship between classes of objects that allows one object instance to cause another to perform an action on its behalf. This relationship is structural, because it specifies that objects of one kind are connected to objects of another and does not represent behaviour.
In generic terms, the causation
is usually called "sending a message
", "invoking a method
" or "calling a member function" to the controlled object. Concrete implementation usually requires the requesting object to invoke a method or member function using a reference or pointer to the memory location of the controlled object.
The objects that are related via the association are considered to act in a role with respect to the association, if object's current state in the active situation allows the other associated objects to use the object in the manner specified by the role. A role can be used to distinguish two objects of the same class when describing its use in the context of the association. A role describes the public aspects of an object with respect to an association.
Object-oriented programming
Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...
, association defines a relationship between classes of objects that allows one object instance to cause another to perform an action on its behalf. This relationship is structural, because it specifies that objects of one kind are connected to objects of another and does not represent behaviour.
Causality
Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....
is usually called "sending a message
Message
A message in its most general meaning is an object of communication. It is a vessel which provides information. Yet, it can also be this information. Therefore, its meaning is dependent upon the context in which it is used; the term may apply to both the information and its form...
", "invoking a method
Method (computer science)
In object-oriented programming, a method is a subroutine associated with a class. Methods define the behavior to be exhibited by instances of the associated class at program run time...
" or "calling a member function" to the controlled object. Concrete implementation usually requires the requesting object to invoke a method or member function using a reference or pointer to the memory location of the controlled object.
The objects that are related via the association are considered to act in a role with respect to the association, if object's current state in the active situation allows the other associated objects to use the object in the manner specified by the role. A role can be used to distinguish two objects of the same class when describing its use in the context of the association. A role describes the public aspects of an object with respect to an association.