When do we need decorator pattern?

Question

When is it necessary to use the decorator pattern? If possible, give me a real world example that is well-suited for the pattern.

Answer 1

If you are familiar with Swing development in Java (along with other GUI toolkits), you'll see the decorator pattern used a lot. You might have a constructor that takes in a specific component and then adds functionality to it.

Here is a good article that uses Swing as an example.