Design pattern is a term that is often heard within software development teams and among IT professionals. It is easy to think that this word would be more at home with creative teams responsible for making graphics design or visual creatives but its origin can be traced back to civil engineering. So, what are design patterns?
Design Pattern in Software Development
In software development, a design pattern is referred to as a general reusable solution to a commonly recurring problem that is encountered during the development process. Design patterns may be viewed as best practices or guidelines to solve common issues or problems in software design and development. Design patterns are documented to ensure that team members can reproduce them in any context. Typically they contain the intent of the solution, the description of the problem they intend to solve, and the motivation behind why the solution was created. They should also include the structure of classes that show how the patterns are related and a code example.Design Patterns vs Algorithms
Design patterns are distinct from algorithms because a design pattern is not a specific set of code that a developer can copy or replicate but more like a framework of a solution or general concept that has a set of guidelines on how to approach and solve a problem. Algorithms, on the other hand, are defined as a clear set of well-defined actions and formulas designed to solve a problem or perform a computation.The Types of Design Patterns
A. Creational Patterns
Creational design patterns focus on object-creation mechanisms that generate objects in a controlled manner. This type of design pattern provides guidance on how objects are created for specific situations or circumstances. The following are examples of creational patterns.| Pattern | Description |
|---|---|
|
Abstract Factory |
Provides an interface for creating objects without specifying classes |
|
Builder |
Helps separate the construction of a complex object from its representation |
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Factory Method |
Creates an object with several derived classes |
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Prototype |
Specifies the kind of objects to create |
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Singleton |
Provides a class with a single instance |
B. Structural Patterns
Structural patterns are like a collection of objects and classes that are built like templates that can be integrated into other objects of the software to form bigger structures or provide new functionality. The following are examples of structural patterns.
| Pattern | Description |
|---|---|
|
Adapter |
Converts or matches the interface of different classes |
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Bridge |
Decouples or separates the object’s interface from its implementation |
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Composite |
Helps compose objects into tree structures and build hierarchies |
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Decorator |
Dynamically adds responsibilities to objects |
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Facade |
Provides a unified interface to a group or set of interfaces |
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Flyweight |
A fine-grained instance that is utilized for efficient sharing |
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Proxy |
A placeholder for another object |
C. Behavioral Patterns
Behavioral patterns focus on dealing with object-oriented software applications. They identify common communication patterns between objects. The following are examples of behavioral patterns.
| Pattern | Description |
|---|---|
|
Chain of Responsibility |
Used to provide loose coupling in which a request is passed between a chain of objects |
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Command |
Used to encapsulate a command request as an object |
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Interpreter |
Used to define a grammatical representation for a language |
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Iterator |
Provides sequential access to elements of a collection |
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Mediator |
A centralized medium of communication between different objects in a system |
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Memento |
Used to save or capture the state of an object so it can be reverted or restored |
|
Null Object |
Null Object |
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Observer |
Used as a way of notifying changes to a number of classes |
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State |
Used to change or alter an object’s behavior when its state changes |
|
Strategy |
Used to encapsulate an algorithm within a class |
|
Template Method |
Used to defer the exact steps of an algorithm to a subclass |
|
Visitor |
Provides a definition of a new operation to a class without change |
Advantages of Using Design Pattern
Design patterns provide software developers and engineers with a set of proven and reusable solutions to help them solve or overcome problems encountered during development.
- Improves Communication: Design patterns help improve the communications between developers and other stakeholders in the team. By standardizing and providing detailed documentation of reusable design patterns, solutions can be easily communicated and discussed.
- Reduces the Complexity of Problem-Solving: Design patterns can help with the problem-solving process by providing developers with defined guidelines on how to approach well-documented or commonly recurring problems encountered during development.
- Improves the Efficiency of Software Development Teams: Design patterns provide teams with scalable and reusable solutions that will help them face a variety of problems encountered during development.
By mastering when and how to use these design patterns, development teams are able to build large-scale applications quickly and efficiently.
