Software design patterns

As software engineers, we all should already know that, when working on a new project, you start by establishing the way of attacking-solving the problem or software to develop. So it is important to get there are these things called patterns (software design patterns) which may help you as a guide to your way of working.

A design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern isn’t a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations.

There are three design patterns we are going to talk about.

Structural

In Software Engineering, Structural Design Patterns are Design Patterns that ease the design by identifying a simple way to realize relationships between entities, making it easier for these to work together.

  • Adapter
    Match interfaces of different classes
  • Bridge
    Separates an object’s interface from its implementation
  • Composite
    A tree structure of simple and composite objects
  • Decorator
    Add responsibilities to objects dynamically
  • Facade
    A single class that represents an entire subsystem
  • Flyweight
    A fine-grained instance used for efficient sharing
  • Private Class Data

    Restricts accessor/mutator access

  • Proxy
    An object representing another object

Creational

In software engineering, creational design patterns are design patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. The basic form of object creation could result in design problems or added complexity to the design. Creational design patterns solve this problem by somehow controlling this object creation.

  • Abstract Factory
    Creates an instance of several families of classes
  • Builder
    Separates object construction from its representation
  • Factory Method
    Creates an instance of several derived classes
  • Object Pool
    Avoid expensive acquisition and release of resources by recycling objects
    ?
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    are no longer in use
  • Prototype
    A fully initialized instance to be copied or cloned
  • Singleton
    A class of which only a single instance can exist

& finally

Behavioral

These design patterns are all about Class’s objects communication. Behavioral patterns are those patterns that are most specifically concerned with communication between objects.

  • Chain of responsibility
    A way of passing a request between a chain of objects
  • Command
    Encapsulate a command request as an object
  • Interpreter
    A way to include language elements in a program
  • Iterator
    Sequentially access the elements of a collection
  • Mediator
    Defines simplified communication between classes
  • Memento
    Capture and restore an object’s internal state
  • Null Object
    Designed to act as a default value of an object
  • Observer
    A way of notifying change to a number of classes
  • State

    Alter an object’s behavior when its state changes

  • Strategy
    Encapsulates an algorithm inside a class
  • Template method
    Defer the exact steps of an algorithm to a subclass
  • Visitor
    Defines a new operation to a class without change

If you are a more listener boy, girl or apache helicopter, then you should watch-listen this video?

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Source: https://sourcemaking.com/design_patterns