𝗗𝗼 𝗬𝗼𝘂 𝗡𝗲𝗲𝗱 𝗧𝗼 𝗞𝗻𝗼𝘄 𝗔𝗹𝗹 𝗗𝗲𝘀𝗶𝗴𝗻 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀? The answer is no. Even though we have 23 design patterns, around 10 are mostly used in everyday development. Knowing which patterns exist overall is good, but you need to know these very well. Design patterns can be divided into three main types: 𝟭. 𝗖𝗿𝗲𝗮𝘁𝗶𝗼𝗻𝗮𝗹 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀 These design patterns deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. Important patterns in this group are: 𝗙𝗮𝗰𝘁𝗼𝗿𝘆: This pattern allows delegating the instantiation logic to factory classes. The Factory Method creates objects without exposing the instantiation logic to the client. 𝗦𝗶𝗻𝗴𝗹𝗲𝘁𝗼𝗻: The Singleton pattern ensures that a class has only one instance and provides a global point of access to it. It's useful when exactly one object is needed to coordinate actions across the system. 𝟮. 𝗦𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗮𝗹 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀 These patterns deal with the composition of classes and objects that form larger structures. Important patterns in this group are: 𝗔𝗱𝗮𝗽𝘁𝗲𝗿: This pattern works as a bridge between two incompatible interfaces. It wraps an existing class with a new interface to become compatible with the client's interface. 𝗙𝗮𝗰𝗮𝗱𝗲: The Façade pattern provides a unified interface to a set of interfaces in a subsystem. Façade defines a higher-level interface that makes the subsystem easier to use. 𝗗𝗲𝗰𝗼𝗿𝗮𝘁𝗼𝗿: This pattern dynamically adds/overrides behavior in an existing method of an object. This pattern provides a flexible alternative to subclassing for extending functionality. 𝗣𝗿𝗼𝘅𝘆: The Proxy pattern provides a surrogate or placeholder for another object to control access to it. In its most general form, a proxy is a class functioning as an interface to something else. 𝟯. 𝗕𝗲𝗵𝗮𝘃𝗶𝗼𝗿𝗮𝗹 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀 These patterns are specifically concerned with communication between objects and how they interact and distribute work. Important patterns in this group are: 𝗖𝗼𝗺𝗺𝗮𝗻𝗱: The Command pattern encapsulates a request as an object, thus allowing users to parameterize clients with queues, requests, and operations. 𝗧𝗲𝗺𝗽𝗹𝗮𝘁𝗲 𝗠𝗲𝘁𝗵𝗼𝗱: This pattern defines the program skeleton of an algorithm in a method called template method, which defers some steps to subclasses. 𝗦𝘁𝗿𝗮𝘁𝗲𝗴𝘆: The Strategy pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it. 𝗢𝗯𝘀𝗲𝗿𝘃𝗲𝗿: This pattern defines a one-to-many dependency between objects so that all its dependents are notified and updated automatically when one object changes state. Check out this helpful cheat sheet below. #softwareengineering #programming #developers