Proxy
Using the proxy pattern, a class represents the functionality of another class. Real world example Have you ever used an access card to go through a door? There are multiple options to open that door i.e. it can be opened either using access card or by pressing a button that bypasses the security. Th…
Flyweight
It is used to minimize memory usage or computational expenses by sharing as much as possible with similar objects. Real world example Did you ever have fresh tea from some stall? They often make more than one cup that you demanded and save the rest for any other customer so to save the resources e.g.…
Facade
Facade pattern provides a simplified interface to a complex subsystem. Real world example How do you turn on the computer? "Hit the power button" you say! That is what you believe because you are using a simple interface that computer provides on the outside, internally it has to do a lot …
Decorator
Decorator pattern lets you dynamically change the behavior of an object at run time by wrapping them in an object of a decorator class. Real world example Imagine you run a car service shop offering multiple services. Now how do you calculate the bill to be charged? You pick one service and dynamical…
Composite
Composite pattern lets clients treat the individual objects in a uniform manner. Real world example Every organization is composed of employees. Each of the employees has the same features i.e. has a salary, has some responsibilities, may or may not report to someone, may or may not have some subordi…
Bridge
Bridge pattern is about preferring composition over inheritance. Implementation details are pushed from a hierarchy to another object with a separate hierarchy. Real world example Consider you have a website with different pages and you are supposed to allow the user to change the theme. What would y…
Adapter
Adapter pattern lets you wrap an otherwise incompatible object in an adapter to make it compatible with another class. Real world example Consider that you have some pictures in your memory card and you need to transfer them to your computer. In order to transfer them you need some kind of adapter th…