Common closure principle
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The Common closure principle is concerned with program maintainability. It states: | The Common closure principle is concerned with program maintainability. It states: | ||
:''The classes in a package should be closed together against the same kind of changes. A change that affects a package affects all the classes in that package.'' [http://ifacethoughts.net/2006/04/08/common-closure-principle/ ifacethoughts.net] | :''The classes in a package should be closed together against the same kind of changes. A change that affects a package affects all the classes in that package.'' [http://ifacethoughts.net/2006/04/08/common-closure-principle/ ifacethoughts.net] | ||
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| + | This means: "The classes that tend to be reused together belong in the same package",[[Robert Cecil Martin 1996b]] | ||
Although most design principles advocate loose-coupling between classes, sometimes it is unavoidable. This may be because of a consequence of the design, or a deliberate action such as performance tuning. In these cases, these classes should be packaged together, so a change only effects the classes in that package. This makes updating the system easier, as only the new package needs to be distributed. The [[Law of Demeter]] is a useful way to find out which classes know other's structure, and thus should probably be in the same package. | Although most design principles advocate loose-coupling between classes, sometimes it is unavoidable. This may be because of a consequence of the design, or a deliberate action such as performance tuning. In these cases, these classes should be packaged together, so a change only effects the classes in that package. This makes updating the system easier, as only the new package needs to be distributed. The [[Law of Demeter]] is a useful way to find out which classes know other's structure, and thus should probably be in the same package. | ||
Revision as of 08:34, 6 October 2008
The Common closure principle is concerned with program maintainability. It states:
- The classes in a package should be closed together against the same kind of changes. A change that affects a package affects all the classes in that package. ifacethoughts.net
This means: "The classes that tend to be reused together belong in the same package",Robert Cecil Martin 1996b
Although most design principles advocate loose-coupling between classes, sometimes it is unavoidable. This may be because of a consequence of the design, or a deliberate action such as performance tuning. In these cases, these classes should be packaged together, so a change only effects the classes in that package. This makes updating the system easier, as only the new package needs to be distributed. The Law of Demeter is a useful way to find out which classes know other's structure, and thus should probably be in the same package.
