Refactoring for High Cohesion

If a method contains several blocks of code that are not well-connected, we may extract new methods from the individual blocks.

If a class is not cohesive because a method is missing but appears in another class, we may move the method to the class to which it belongs.

• In the tic tac toe example from the previous section, this took the form of moving the makeMove method from the GUI class to the business logic class (Board).

Similarly, if a if a method isn't connected with any other methods in the same class, it should likely be moved out to where it belongs.

Modularity and cohesion are closely related, so share many named refactorings.

Book example: does a PiggyBank class need to know about Nickels or Dimes, or would it be better to abstract that information into a Coin class?