Extract Method

Revision as of 10:32, 14 October 2009

Extracting a method consists of turning a fragment of a method into a method whose name explains the purpose of the method. This may need to be used in methods that show a large number of local variables within the scope of a method, to enhance comprehensibility and reduce complexity. If several of these local-scope variables are modified by the code extracted, Split Temporary Variable may also need to be used.

In cases where extracting a method is not feasible, replacing the method with a Method Object may be the next step.

Example:

printOwing() {
               printBanner();
       
               //print details
               System.out.println ("name:	" + _name);
               System.out.println ("amount	" + getOutstanding());
       }

becomes

       void printOwing() {
               printBanner();
               printDetails(getOutstanding());
       }

       void printDetails (double outstanding) {
               System.out.println ("name:	" + _name);
               System.out.println ("amount	" + outstanding);
       }

See Also