Design patterns have become an essential part of the designing world. They are design level solution for the common problems in software design. A design pattern is not the finished version of the plan, which can be transformed directly to code, but it is a design template that can solve problems leading to different situations.
Design patterns can speed up your development process by providing tested, verified development models. Effective software designing requires solutions that may not be visible until the implementation. Using design patterns helps in preventing the issues that can cause a significant problem later and improves code readability for coders and designers familiar with the pattern.
Often, it can be difficult for designers to understand the application of certain design technique to a certain problem. Design patterns provide a general solution, developed in a format that doesn’t require specifics tied to a specific problem. Think of it like logo templates for logo design service used by non-designers to create an out of the box design.
Here are eight design patterns that every designer and developer must understand.
One of the broadly utilised design patterns, Singleton is used when an object is needed to coordinate action across the system. It is a design pattern used to create a class limited to a single object. It ensures that the class has only one instance and provides global access to that instance.
The factory method design pattern is an abstract class for the creation of objects where the subclasses decide the instantiate. It makes the design more customizable, but it can get a little complicated. Unlike other design patterns, needing new classes, factory method requires a new operation.
Strategy method design pattern is a behavioural design pattern allowing grouping of related algorithms in abstraction, burying the implementations details in derived classes. It lets the algorithms switch independently without modifying the clients.
Also classified among the behavioural pattern designs, the observer design pattern can be described as one-to-many dependency between objects, so when it changes its state, all its dependents are notified automatically. To simplify, think of what happens when you follow someone of Instagram. You ask the platform to send you (the observer) updates of the person (the subject) you followed. The pattern consists of two actors—the observer and the subject. A subject can have many observers, as it happens on Instagram. Similarly an observer is free to subscribe for updates from many subjects as well.
Builder pattern builds objects. Sometimes the objects created can be complicated, made up of different sub-objects or may require a detailed development process. This complexity of the creation of objects can be simplified with the use of builder design pattern. The builder pattern may seem similar to abstract factory, but they are different from one and other. Builder pattern builds the object step by step, while abstract factory returns it in one go.
This design pattern allows the incompatible classes to work together by converting the interface of one class to another. Think of it as a translator who can enable communication between the two classes making them work seamlessly.
The state pattern can express the various states of a machine. It allows the object to modify its behaviour when its internal state alters. Actions can be taken by the machine so it can change it into different states. Without using the state pattern, the code used become inflexible and besieged with if-else conditionals.