Push Down Field

A field is used only by some subclasses.

Move the field to those subclasses.

Motivation

Push Down Field is the opposite of Pull Up Field. Use it when you don’t need a field in the superclass but only in a subclass.

Mechanics

• Declare the field in all subclasses.
• Remove the field from the superclass.
• Compile and test.
• Remove the field from all subclasses that don’t need it.
• Compile and test.