Moving Features between Objects.

Problem: When one class does the work of two, awkwardness results. Solution: Instead, create a new class and place the fields and methods responsible for the relevant functionality in it.

Problem: The client gets object B from a field or method of object А. Then the client calls a method of object B. Solution: Create a new method in class A that delegates the call to object B. Now the client doesn’t know about, or depend on, class B.

Problem: A class does almost nothing and isn’t responsible for anything, and no additional responsibilities are planned for it. Solution: Move all features from the class to another one.

Problem: A utility class doesn’t contain the method that you need and you can’t add the method to the class. Solution: Add the method to a client class and pass an object of the utility class to it as an argument.

Problem: A utility class doesn’t contain some methods that you need. But you can’t add these methods to the class. Solution: Create a new class containing the methods and make it either the child or wrapper of the utility class.

Problem: A field is used more in another class than in its own class. Solution: Create a field in a new class and redirect all users of the old field to it.

Problem: A method is used more in another class than in its own class. Solution: Create a new method in the class that uses the method the most, then move code from the old method to there. Turn the code of the original method into a reference to the new method in the other class or else remove it entirely.

Problem: A class has too many methods that simply delegate to other objects. Solution: Delete these methods and force the client to call the end methods directly.