Code-Refactoring

Duplicated Code

• copying and pasting same code whenever need.
• copy a bulk chunk and edit a small portion of it.

Long Methods

problem:

• methods that do more than one thing. these kind of methods might become more than 8 to 10 lines

solution:

• split them up into small methods

Complex Conditional Statements

problem:

• nested ternary operation
• nested if else
• making comparison with magic numbers like 1, 10, 20
• too many parenthesis, &&, || so that to understand the logic takes more than 1min of time.

solution:

• try to avoid them by rethinking the condition
• try to avoid by calling a function with meaningful name

Primitive Obsession

problem:

• without using object we use decimal, string, array to solve our problem.

solution:

• try to think as entity and create a class, encapsulate it behavior into it.

Indecent Exposure

problem:

• exposing methods which is not needed. making very complex for client to understand which method should be used

solution:

• encapsulate methods
• may expose one single method which does combining multiple methods under the hood.

Solution Sprawl

problem:

• when code and/or data used to perform a single responsibility becomes sprawled across numerous classes. it occurs when we add features quickly without spending enough time to simplify and consolidate the design

solution:

• combine all those responsibility into one class

Alternative Classes with Different Interfaces

problem:

• when similar classes have different interfaces.

solution:

• its better to combine those interfaces into one.

Lazy Classes

problem:

• these classes doesn't do much on their own. just used for small helping methods

solution:

• remove the class and take those method inside the class which uses it.

Large Classes

problem:

• this occurs when we move too much lazy classes into one class.
• this can also occur when we use instances of that class over and over again in different places for different purposes.

solution:

• a class should have a single reason to change. that indicate a class should be small which can perform single responsibility

Switch Statements

problem:

• if these are used for the sake of different type problem.

solution:

• we should replace them with an object by polymorphic solution

Combinatorial Explosions

problem:

• it happens when we create lots of methods to do one thing. like creating methods for each database query.

solution:

• instead of that we can create a single method which handle numerous query.

Oddball Solutions

problem:

• when we solve same problem in different ways.

solution:

• only keep the one which is the best considering the constrains and remove others

Techniques

Creation Method

• replace constructor with different descriptive named creation methods. Its advantage is that we don't need to call new.