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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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          5 | 
           * **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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          -* S**eparate statement and query.** Functions should either provide information about an object or do something with an object, but not both. | 
        
              
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          +* The flow of reading should follow the flow of control. [[Here|doc:.Function Ordering Example.WebHome]] is an example. | 
        
              
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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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          7 | 
           * **Exceptions are better than error codes** (with if/else statements). | 
        
              
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          8 | 
               * 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. | 
        
              
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          9 | 
               * Extract try/catch blocks. Error processing is a task. So it deserves its own function. |