DesginPatterns

Table Of Contents

Behavioral
- Observer Pattern
Strcutural
- Adapter Pattern

Behavioral :

Observer Pattern

One object notifies other objects about its state change.
It is a one-to-many relationship.
When the state of one object changes, other object which are subscribed to it gets notified about the state change.
Observable protocol has three abstract methods :
- add(observerX) : to add an observer.
- remove(observerX) : to remove a specific observer.
- notify() : to notify all observers.

Code example here

Implementation

Strcutural :

Adapter Pattern

Named also Wrapper.
Allows objects with incompatible interfaces to collaborate.
lets you create a middle-layer class that serves as a translator between your code and a legacy class, a 3rd-party class or any other class with a weird interface.
Do not add an additional behavior.

Code example here

Implementation