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--- principles:high_cohesion [2013-02-25 14:06] – [Further Reading] christian
+++ principles:high_cohesion [2019-05-29 15:09] – old revision restored (2016-09-03 22:52) christian
@@ Line 6: / Line 6: @@
 ===== Context =====
 /* fill in contexts here: */
   * [[contexts:Object-Oriented Design]]
+  * [[contexts:API Design]]
+  * [[contexts:Architecture]]
@@ Line 19: / Line 21: @@
 Several kinds of cohesion can be distinguished some of which are strong and some of which are loose. So strong forms of coupling should be preferred: FIXME add explanation of cohesion types
 ===== Rationale =====
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   * Divide one large module into several smaller but more cohesive ones
 ===== Caveats =====
@@ Line 34: / Line 38: @@
 ===== Origin =====
+W. P. Stevens,  G. J. Myers, L. L. Constantine: //Structured design//
 ===== Evidence =====
@@ Line 39: / Line 44: @@
 /*[[wiki:Proposed]]*/
-  * [[wiki:Examined]]
+  * [[wiki:Examined]]: There are metrics that try to measure cohesion and there are studies relating these cohesion measures to the number of errors found during testing (({{page>resources:A Handbook Of Software And Systems Engineering#reference}})). This correlation is evident. The limitation of these studies is that these cohesion metrics cannot represent the cohesion notion completely.
-  * [[wiki:Accepted]]
+  * [[wiki:Accepted]] The concept of high cohesion is widely known and described in several well-known books for example in {{page>resources:Applying UML And Patterns#reference}}.
 /*[[wiki:Questioned]]*/
@@ Line 73: / Line 78: @@
-===== Example =====
+===== Examples =====
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 /*[[wiki:Incomplete]]*/
 /*[[wiki:Complete]]*/
+==== Class level cohesion ====
+Robert Cecil Martin (Uncle Bob) describes maximal cohesion at class level as "a class in which each variable is used by each method".
+"In general the more variables a method manipulates the more cohesive that method is to its class."
+(Clean Code: A Handbook of Agile Software Craftsmanship - Chapter 10)
 ===== Further Reading =====
-  * Albert Endres and Dieter Rombach: //A Handbook of Software and Systems Engineering//. p. 43pp.
+  * Albert Endres and Dieter Rombach: //[[resources:A Handbook of Software and Systems Engineering]]//. p. 43pp.
   * [[wp>Cohesion (computer science)]]
   * [[wiki>CouplingAndCohesion]]
-  * Craig Larman: //Applying UML and Patterns – An Introduction to Object-Oriented Analysis and Design and Iterative Development//
+  * {{page>resources:Applying UML And Patterns#reference}}
+===== Discussion =====
+Discuss this wiki article and the principle on the corresponding [[talk:principles:High Cohesion|talk page]].