principles:high_cohesion
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| principles:high_cohesion [2013-02-18 17:24] – external edit 127.0.0.1 | principles:high_cohesion [2021-09-02 12:37] – old revision restored (2021-03-25 15:16) 65.21.179.175 | ||
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| ===== Strategies ===== | ===== Strategies ===== | ||
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| - | * Divide one large module into several smaller but more cohesive ones | ||
| - | ===== Caveats ===== | ||
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| - | See section [[#contrary principles]]. | ||
| ===== Origin ===== | ===== Origin ===== | ||
| + | /* the *primary* source */ | ||
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| * [[More Is More Complex]] (MIMC): Making a module highly cohesive often results in additional modules. Sometimes it is simpler to assign a minor unrelated responsibility to a module, which lowers the cohesion. | * [[More Is More Complex]] (MIMC): Making a module highly cohesive often results in additional modules. Sometimes it is simpler to assign a minor unrelated responsibility to a module, which lowers the cohesion. | ||
| * [[Model Principle]] (MP): Adhering to HC sometimes means to split up a class into several smaller ones which might correspond to the model less well. | * [[Model Principle]] (MP): Adhering to HC sometimes means to split up a class into several smaller ones which might correspond to the model less well. | ||
| - | * [[Low Coupling]] (LC): A system consisting of one single module has a very low coupling as there are no dependencies on other modules. But such a system also has low cohesion. The other extreme, very many highly cohesive modules, naturally has a higher coupling between the modules. So here a compromise has to be found. | ||
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| ==== Complementary Principles ==== | ==== Complementary Principles ==== | ||
| + | * [[Low Coupling]] (LC): A system consisting of one single module has a very low coupling as there are no dependencies on other modules. But such a system also has low cohesion. The other extreme, very many highly cohesive modules, naturally has a higher coupling between the modules. So here a compromise has to be found. | ||
| * [[Encapsulate the Concept that Varies]] (ECV): Adhering to HC often results in modules to be split up into several more cohesive ones. ECV gives further advice on how to do that. | * [[Encapsulate the Concept that Varies]] (ECV): Adhering to HC often results in modules to be split up into several more cohesive ones. ECV gives further advice on how to do that. | ||
principles/high_cohesion.txt · Last modified: 2021-10-18 21:36 by christian