Temporary Field

A Temporary Field smell occurs when a variable that should be defined within a method’s scope is instead defined in the class’ scope.

This violates the information hiding principle, since all the methods in the class will have access to this variable, when only one method needs it.

Another issue this smell causes, is the unreliability of instance variables, since this instance variable would only be updated when the method is run, but we expect instance variables to reliably track information about our objects at all times.

Books about code smells

Learn to write better smelling code.

Refactoring: Improving the Design of Existing Code

Code smells: A Predictor of Remarkable Quality Improvement

Clean Code: A Handbook of Agile Software Craftsmanship