Inappropriate Intimacy

Description (What)

A class uses the internal fields and methods of an object directly

How to Locate It (Where)

Look for public fields being access by other classes. Classes should know as little about each other as possible.

How It Manifests (Why)

Can occur due to fields being public and being accessed by other classes because it is easier to do instead of creating a getter/setter method.

How to Fix It (Possible Treatments)

In Example 1, Hide Delegate is used. This treatment requires you to create getter and setter methods for the field that needs to be accessed to allow for an "official" relationship as compared to dirt mutating. If a public method is also being accessed along with the fields it is better to first Extract Class and create a new class and then move the fields and methods to that new class and use it from there.

In Example 2, Replace Delegate with Inheritance is used. Because the associations between the classes need to be corrected.

A Delegation is inappropriate in the particular case, instead, an inheritance should be adopted.

Other treatments are also possible based on the specific scenario, they can be found here

Examples

Example 1

Before:

Library class uses the internal fields of Book class as they are marked as public.

Observed Code Smells:
- Inappropriate Intimacy (lines 38, 43, 44)

After:

Applied Hide Delegate to make field private and create a getter for the field instead to make the relation "official" instead of directly mutating the field. This is step 2 of the Extract Class and Hide Delegate treatment but since only a field is being accessed, the Extract Class part seems unecessary and making the field private from public seems to be enough.

Refactoring Applied:
- Inappropriate Intimacy
    - Hide Delegate

Observed Code Smells After Refactoring:
- None

Example 2

Before:

Imagine this coffee machine is making 4 types of coffee:

Espresso (hot only), Americano(iced and hot), Latte(iced and hot), CafeMocha(iced and hot).

The interface is Coffee, which is firstly implemented by an AbstractCoffee class and then these 4 types of coffees.

The problem lies on when the machine starts to make a CafeMocha, it grabs a Latte first and continue working on

top of that Latte; Even though the final ingredients are correct, private fields and methods from class Latte are

constantly used in class CafeMocha. Same wrong pops out for Espresso and Americano as well.

Observed Code Smells:
- Inappropriate Intimacy (line 78, line 82, line 91, line 131, line 135, line 145)

After:

Applied Replace Delegate with Inheritance to get the thing done easier and get rid of the Inappropriate Intimacy.


Refactoring Applied:
- Inappropriate Intimacy
  - Replace Delegate with Inheritance (lines 78, line 88, line 100, line 109, lines 138, line 141, line 149, line 154, 
                                       line 159)

Observed Code Smells After Refactoring:
- None.

When to Ignore

None

More about Inappropriate Intimacy

Example 1
Example 2

Before
After

001  import java.util.HashMap;
002  import java.util.Map;
003  
004  class Book {
005      public String name;
006      public String genre;
007      public boolean isIssued;
008  
009      public Book(String name, String genre) {
010          this.name = name;
011          this.genre = genre;
012          this.isIssued = false;
013      }
014  
015      public void displayDetails() {
016          System.out.println("Name: " + this.name);
017          System.out.println("Genre: " + this.genre);
018          System.out.println("Is issued: " + this.isIssued);
019      }
020  }
021  
022  class Library {
023      Map<Integer, Book> books;
024  
025      public Library() {
026          this.books = new HashMap<>();
027      }
028  
029      public void addBook(int id, Book book) {
030          this.books.put(id, book);
031      }
032  
033      public void removeBook(int id) {
034          this.books.remove(id);
035      }
036  
037      public void issueBook(int id) {
038          books.get(id).isIssued = true;
039      }
040  
041      public void viewNonIssuedBooks() {
042          for(Map.Entry<Integer, Book> book: books.entrySet()) {
043              if(book.getValue().isIssued == false) {
044                  System.out.println(book.getValue().name + " - " + book.getValue().genre);
045              }
046          }
047      }
048  }
049  
050  public class IIBE1 {
051      public static void main(String[] args) {
052          Library snell = new Library();
053          Book animalFarm = new Book("Animal Farm", "Satire");
054          Book ofMiceAndMen = new Book("Of Mice and Men", "Theatre");
055          snell.addBook(1, animalFarm);
056          snell.addBook(2, ofMiceAndMen);
057          snell.issueBook(1);
058          snell.viewNonIssuedBooks();
059      }
060  }