Smells

Question 1

Define Duplicated Code

Answer 1

Two code fragments look almost identical.

Question 2

Define Long Method

Answer 2

A method contains too many lines of code. Generally, any method longer than ten lines should make you start asking questions.

Question 3

Define Large class

Answer 3

A class contains many fields/methods/lines of code.

Question 4

Define long parameter list

Answer 4

More than three or four parameters for a method.

Question 5

define divergent change

Answer 5

You find yourself having to change many unrelated methods when you make changes to a class. For example, when adding a new product type you have to change the methods for finding, displaying, and ordering products.

Question 6

define shotgun surgery

Answer 6

Making any modifications requires that you make many small changes to many different classes.

Question 7

define feature envy

Answer 7

A method accesses the data of another class more than its own.

Question 8

define data clumps

Answer 8

Sometimes different parts of the code contain identical groups of variables (such as parameters for connecting to a database). These clumps should be turned into their own classes.

Question 9

define primitive obsession

Answer 9

Use of primitives instead of small objects for simple tasks (such as currency, ranges, special strings for phone numbers, etc.)

Use of constants for coding information (such as a constant USER_ADMIN_ROLE = 1 for referring to users with administrator rights.)

Use of string constants as field names for use in data arrays.

Question 10

define switch statements

Answer 10

You have a complex switch operator or sequence of if statements.

Fowler: using switch statements on type of object when you should be using subclasses/polymorphism

Question 11

define lazy class

Answer 11

Understanding and maintaining classes always costs time and money. So if a class doesn’t do enough to earn your attention, it should be deleted.

Question 12

define speculative generality

Answer 12

There’s an unused class, method, field or parameter.

Question 13

define message chains

Answer 13

In code you see a series of calls resembling $a->b()->c()->d()

Question 14

define middle man

Answer 14

If a class performs only one action, delegating work to another class, why does it exist at all?

Question 15

define inappropriate intimacy

Answer 15

One class uses the internal fields and methods of another class.

Question 16

define data class

Answer 16

A data class refers to a class that contains only fields and crude methods for accessing them (getters and setters). These are simply containers for data used by other classes. These classes don’t contain any additional functionality and can’t independently operate on the data that they own.

Question 17

define refused bequest

Answer 17

If a subclass uses only some of the methods and properties inherited from its parents, the hierarchy is off-kilter. The unneeded methods may simply go unused or be redefined and give off exceptions.

Question 18

define comments

Answer 18

A method is filled with explanatory comments.