When to use which design pattern? [closed]

Answer 1

I completely agree with @Peter Rasmussen.

Design patterns provide general solution to commonly occurring design problem.

I would like you to follow below approach.

1. Understand intent of each pattern
2. Understand checklist or use case of each pattern
3. Think of solution to your problem and check if your solution falls into checklist of particular pattern
4. If not, simply ignore the design-patterns and write your own solution.

Useful links:

sourcemaking : Explains intent, structure and checklist beautifully in multiple languages including C++ and Java

wikipedia : Explains structure, UML diagram and working examples in multiple languages including C# and Java .

Check list and Rules of thumb in each sourcemakding design-pattern provides alram bell you are looking for.