Martin Fowlers Refactorings

Here is a complete list of the refactorings that Martin Fowler recommends using. This a direct pull from the Table of Contents of his book Refactoring: Improving the Design of Exsting Code. There are about six other chapters in the book, but this is his description of the techniques for refactorings that he recomends. This is the classic book on this subject, and I highly recommend buying it.

Composing Methods.

• Extract Method.
• Inline Method.
• Inline Temp.
• Replace Temp with Query.
• Introduce Explaining Variable.
• Split Temporary Variable.
• Remove Assignments to Parameters.
• Replace Method with Method Object.
• Substitute Algorithm.

Moving Features Between Objects.

• Move Method.
• Move Field.
• Extract Class.
• Inline Class.
• Hide Delegate.
• Remove Middle Man.
• Introduce Foreign Method.
• Introduce Local Extension.

Organizing Data.

• Self Encapsulate Field.
• Replace Data Value with Object.
• Change Value to Reference.
• Change Reference to Value.
• Replace Array with Object.
• Duplicate Observed Data.
• Change Unidirectional Association to Bidirectional.
• Change Bidirectional Association to Unidirectional.
• Replace Magic Number with Symbolic Constant.
• Encapsulate Field.
• Encapsulate Collection.
• Replace Record with Data Class.
• Replace Type Code with Class.
• Replace Type Code with Subclasses.
• Replace Type Code with State/Strategy.
• Replace Subclass with Fields.

Simplifying Conditional Expressions.

• Decompose Conditional.
• Consolidate Conditional Expression.
• Consolidate Duplicate Conditional Fragments.
• Remove Control Flag.
• Replace Nested Conditional with Guard Clauses.
• Replace Conditional with Polymorphism.
• Introduce Null Object.
• Introduce Assertion.

Making Method Calls Simpler.

• Rename Method.
• Add Parameter.
• Remove Parameter.
• Separate Query from Modifier.
• Parameterize Method.
• Replace Parameter with Explicit Methods.
• Preserve Whole Object.
• Replace Parameter with Method.
• Introduce Parameter Object.
• Remove Setting Method.
• Hide Method.
• Replace Constructor with Factory Method.
• Encapsulate Downcast.
• Replace Error Code with Exception.
• Replace Exception with Test.

Dealing with Generalization.

• Pull Up Field.
• Pull Up Method.
• Pull Up Constructor Body.
• Push Down Method.
• Push Down Field.
• Extract Subclass.
• Extract Superclass.
• Extract Interface.
• Collapse Hierarchy.
• Form Template Method.
• Replace Inheritance with Delegation.
• Replace Delegation with Inheritance.

Big Refactorings.

• Tease Apart Inheritance.
• Convert Procedural Design to Objects.
• Separate Domain from Presentation.
• Extract Hierarchy.