Design Patterns

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Design patterns :: are typical solutions to common problems in software design. #AOSR/75jm7/s/53fg
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Design patterns are reusable to commonly occurring design problems in software development.

Advantages

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Key benefits of design patterns ::

Reusability: Design patterns provide reusable solutions to common problems in software design.
Maintainability: Design patterns promote clean and organized code structures.
Scalability: Design patterns help create flexible and extensible code.
Abstraction: Patterns abstract common design principles into well-defined templates.
Communication: Design patterns provide a common vocabulary for developers to discuss and communicate design decisions.
Testability: Code structured using design patterns often leads to more testable software.
Performance Optimization: Some design patterns, such as the Singleton pattern, can help optimize performance by ensuring that specific objects are instantiated only once.
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Elements of Design Patterns

Pattern Name: A descriptive name that represents the essence of the pattern.
Problem: A description of the design problem or scenario that the pattern addresses.
Solution: The actual design solution that addresses the problem.
Consequences and trade-offs of application: Consequences are the outcomes or effects that result from applying a design pattern to your software design. Trade-offs are the compromises you make when choosing a particular design pattern.

Design Patterns Templates

Name

Describe the essence of the pattern in short

Intent

A brief statement describing the purpose and goal of the design pattern.

Also Known As

other names that people have for the pattern

Motivation

Explain the problem or scenario the design pattern aims to address. Discuss the context and conditions under which the pattern becomes relevant.

Applicability

Describe the situations where the design pattern is most appropriate. This includes scenarios where the pattern can be effectively used to improve the design, structure, or behavior of the software.

Structure

Provide an overview of the components and relationships involved in the design pattern. You can use diagrams or textual descriptions to illustrate the structure.

Participants

List the key elements or classes involved in the pattern and explain their roles.

Collaborations

Explain how the participants interact and collaborate to achieve the pattern's goals.

Consequences

Outline the positive and negative effects of applying the design pattern. This includes the benefits gained, as well as any trade-offs or drawbacks that need to be considered.

Implementation

Provide guidance on how to implement the design pattern in code. This can include code snippets, code structures, and best practices for integrating the pattern into your software.

Sample Code (Optional)

If appropriate, provide a complete or partial code example to showcase how the pattern can be implemented in a real-world scenario.

Known Uses (Optional)

Highlight any well-known software systems or projects that utilize this design pattern.

Discuss any relationships between the current design pattern and other design patterns. This could include variations, alternatives, or complementary patterns.

References

List any sources, books, articles, or online resources where readers can find more information about the design pattern.

Classification of Design Patterns

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Creational Patterns :: Creational patterns deal with the process of object creation. They provide ways to instantiate objects while hiding the exact logic of how objects are created and initialized. #AOSR/3bf4v/s/3m08
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Structural Patterns :: Structural patterns is a blueprint of how different objects and classes are combined together to form a bigger structure for achieving multiple goals altogether. #AOSR/1pjr4/s/5ijg
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Behavioral Patterns :: Behavioral patterns are concerned with the interactions between objects and the distribution of responsibilities. #AOSR/2fr2o/s/70ud
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Creational Design Patterns

Singleton Pattern

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Singleton Pattern :: Ensures that a class has only one instance and provides a global point of access to that instance. #AOSR/58ck3/s/6pua
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public class Singleton {
    // Private static instance variable
    private static Singleton instance;

    // Private constructor to prevent instantiation from other classes
    private Singleton() {
        // Initialization code, if needed
    }

    // Public method to get the singleton instance
    public static Singleton getInstance() {
        if (instance == null) {
            instance = new Singleton();
        }
        return instance;
    }

    // Other methods and fields can be added here as needed
}

Factory Method Pattern

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Factory Method Pattern :: is an interface for creating objects but allows subclasses to decide which class to instantiate. #AOSR/5640r/s/51p5

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Abstract Factory Pattern

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Abstract Factory Pattern :: provides an interface for creating families of related or dependent objects without specifying their concrete classes. #AOSR/6vrhk/s/5uvr
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Builder Pattern

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Builder pattern :: separates the construction of a complex object from its representation, allowing the same construction process to create different representations. #AOSR/4194s/s/2fv3
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Structural Design Patterns

Composite Pattern

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The Composite Pattern :: is used to compose objects into tree structures to represent part-whole hierarchies. #AOSR/434h8/s/7vvc
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Adapter Pattern

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The Adapter Pattern :: also known as the Wrapper pattern, allows objects with incompatible interfaces to work together. #AOSR/2fbpq/s/4dun
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Proxy Pattern

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The Proxy Pattern :: provides a surrogate or placeholder for another object to control access, add security, or provide additional functionality. #AOSR/ao0sr/s/hnho
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Facade Pattern

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The Facade Pattern :: provides a simplified interface to a complex subsystem, making it easier to interact with and understand. #AOSR/6jasi/s/5kti
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Behavioral Design Patterns

Observer Pattern

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The Observer Pattern :: defines a one-to-many dependency between objects, where when one object (the subject) changes state, all its dependents (observers) are notified and updated automatically. #AOSR/3pvub/s/z772
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Template Pattern

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The Template Pattern :: defines the structure of an algorithm in a superclass but allows subclasses to override specific steps of the algorithm. #AOSR/4la14/s/1rtr
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Strategy Pattern

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The Strategy Pattern :: defines a family of interchangeable algorithms and allows them to be used interchangeably within a context. #AOSR/5kuu4/s/6c9c
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Iterator Pattern

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The Iterator Pattern :: provides a way to access elements of a collection without exposing its underlying representation. #AOSR/7m9mu/s/4rmh
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