Inheritance vs Composition

Object-Oriented Programming (O.O.P.) has been relevant in the land of programming. For this article, the two most commonly used concepts will be discussed. This article provides surface-level knowledge between the two. Java will be the programming language used.

Composition

This is a concept with a has-a relationship between classes. The code below showcases this using the Java programming language.

class Caret { Caret() {} } class TextEditor { Caret caret; TextEditor() { caret = new Caret(); } } class RichTextEditor { Caret caret; String color; RichTextEditor(String color) { caret = new Caret(); this.color = color; } } 

The code above states that the class, TextEditor has a caret and a color. In other words, it is made up of the aforementioned fields.

The RichTextEditor has a caret and color. It does not depend on the TextEditor class, unlike in inheritance; which will be shown below.

Composition is like making food. The main class is the food and its ingredients are its fields/properties.

Inheritance

This is a concept with an is-a relationship between classes and is only limited to being one-to-one. The code below showcases this using the Java programming language.

class Caret { public Caret() {} } class TextEditor { Caret caret; TextEditor() { caret = new Caret(); } } class RichTextEditor extends TextEditor { String color; RichTextEditor(String color) { super(); this.color = color; } } 

The code above states that the RichTextEditor class inherits from the TextEditor class. Everything that in TextEditor becomes a part of RichTextEditor.

Now, for our food analogy, let's say that Jollibee spaghetti inherits from spaghetti. If we change spaghetti to be a carbonara, for whatever reason, then our Jollibee spaghetti would then become a Jollibee carbonara without us touching it!

Conclusion

That's it! Thank you for reading. May you have a wonderful day. Happy coding. God bless! :)