Coupling (computer programming): Difference between revisions

Revision as of 16:41, 11 November 2005

Revision as of 17:16, 11 November 2005

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== Low-Coupling / High-Cohesion ==

Low-Couplingcoupling / Highhigh-Cohesioncohesion is a general goal to achieve when structuring [[computer program]]s, so that they are easier to understand and maintain.

The concepts (Low-Coupling / High-Cohesion) are usually related.: Lowlow coupling implies high cohesion and viceversa,vice becauseversa. ifIn wethe putfield togetherof all relationed methods[[object-oriented (High Cohesion)programming]], the connection between classes tends to get lower (Lowlow Couplingcoupling), if we we group related methods of a class together (high cohesion).

=== Low Coupling ===

CouplingIn object-oriented programming, coupling is a measure of how strongly one class is connected to another and is increased between Class A and Class B when:.

Coupling is increased between two classes A and B if:

*A has an attribute that refers to (is of type) B.

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*A is a subclass of (or implements) B.

The disadvantagesDisadvantages of high coupling includesinclude:

*A change in one class forces a ripple of changes in other classes.

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*Operations do many varied activities, often using varied data.

The disadvantagesDisadvantages of weak cohesion are:

*Difficult to understand.

*Difficult to maintain, because it is constantly affected by changes.

*Difficult to reuse a class because most applicationapplications won’t need a random set of operations attached to a class.

=== Related patterns ===