Unified Solutions for Software Problems
Design patterns are tried-and-true, reusable solutions to common problems in software design. They were first defined in the seminal book, “Design Patterns: Elements of Reusable Object-Oriented Software,” by authors Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, collectively known as the Gang of Four (GoF).
Categories of Design Patterns:
1. Creational Patterns:
Focus on object creation mechanisms, enhancing flexibility and reusability.
Examples include:
-Simple Factory
Used to create objects of a specific type without needing to know how they are created.
-Abstract Factory
Creates families of related objects without specifying their concrete classes.
-Builder
Constructs complex objects step by step.
-Prototype
Creates new objects by copying an existing object.
-Singleton
Ensures a class has only one instance.
2. Structural Patterns:
Aim to simplify design by establishing straightforward ways to build complex relationships between objects.
Examples include:
-Adapter
Makes two incompatible objects work together.
-Bridge
Separates an object’s interface from its implementation.
-Composite
Treats a group of objects as a single object.
-Decorator
Adds new functionalities to an object without altering its structure.
-Facade
Provides a simple interface to a complex system of objects.
-Flyweight
Reduces memory usage by sharing as much state as possible with other similar objects.
-Proxy
Controls access to another object.
3. Behavioral Patterns:
Focus on improving communication between disparate objects, facilitating how objects interact and distribute responsibilities among them.
Examples include:
- Chain of Responsibility
Passes a request along a chain of objects until it is handled.
-Command
Executes a request without knowing the requester.
-Interpreter
Parses a series of symbols into a structured data format.
-Mediator
Facilitates communication between objects without them needing to be aware of each other.
-Memento
Saves and restores an object’s state.
-Observer
Notifies objects about changes in another object.
-State
Changes an object’s behavior based on its current state.
-Strategy
Defines an object’s behavior without changing its class.
-Template Method
Defines the skeleton of an algorithm, allowing subclasses to alter some steps.
-Visitor
Allows for new operations to be defined on a data structure without changing its elements.
The Importance of Design Patterns:
Improves Code Maintainability and Comprehension
Design patterns enhance the readability and maintainability of code by offering clear, tested solutions to common problems.
Facilitates Code Reusability and Abstraction
By abstracting away details, design patterns make applications more adaptable to future changes.
Eases Communication Among Developers
When working in teams, design patterns provide a shared language to discuss complex solutions more effectively
Minimizes Potential Design Errors
Leveraging proven and tested solutions can cover common scenarios and reduce the likelihood of errors in the design phase.