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* **Functions should be small.** Maximum 20 lines. Blocks and indentation should also be short. Blocks inside if, else, or while statements should be one line. A function call should probably be included. Indentation depths should be no more than one or two levels. |
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* **Functions should do only one task.** They should do its task well. They should do only that task. All instructions within the function should be on the same abstraction level. Sub-functions perform tasks which are one abstraction-level deeper. Sections within a function are symptoms that it performs more than one task. These function should be decomposed. |
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* **One abstraction level per function.** The 'stepdown rule' states that code should be easy to read from top to bottom: Under a function, its subfunctions should go down one level of abstraction. |
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-* **The flow of reading should follow the flow of control.** The flow of control is the chronological order in which code is executed. The order of the functions should be adjusted accordingly. [[Here|doc:.Function Ordering Example.WebHome]] is an example. |
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+* The flow of reading should follow the flow of control. Here is an example: |
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+ |
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+``` |
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+func_1() { |
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+ func_2() |
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+ func_3() |
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+} |
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+ |
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+func_2() { |
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+ func_4 |
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+} |
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+ |
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+func_4() { |
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+ ... |
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+} |
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+ |
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+func_3(){ |
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+ ... |
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+} |
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+``` |
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+ |
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* **Separate statement and query.** Functions should either provide information about an object or do something with an object, but not both. |
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* **Exceptions are better than error codes** (with if/else statements). |
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* Error.java is a dependency magnet with its enumeration of error codes and should be replaced by exceptions and derivatives of the Exception class, which allows easy extensibility in accordance with the Open-Closed Principle. |
