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🎉 Ultra-simplified explanation to design patterns! 🎉
A topic that can easily make anyone's mind wobble. Here I try to make them stick in to your mind (and maybe mine) by explaining them in the simplest way possible.
This work, "C++ Design Patterns for Humans", is a derivative of "Design Patterns for Humans" by "kamranahmedse", used under CC BY 4.0.
Introduction
Design patterns are solutions to recurring problems; guidelines for how to tackle certain problems. They are not classes, packages, or libraries that you can plug into your application and wait for the magic to happen. These are, rather, guidelines on how to tackle certain problems in certain situations.
Design patterns are solutions to recurring problems; guidelines for how to tackle certain problems.
Wikipedia describes design patterns as:
[...] a general reusable solution to a commonly occurring problem within a given context in software design. It is not a finished design that can be transformed directly into source or machine code. It is a description or template for how to solve a problem that can be used in many different situations.
⚠️ Be Careful
- Design patterns are not a silver bullet to all your problems.
- Do not try to force them; bad things are supposed to happen, if done so.
- Keep in mind that design patterns are solutions to problems, not solutions finding problems; so don't overthink.
- If used in a correct place in a correct manner, they can prove to be a savior; or else they can result in a horrible mess of a code.
Types of Design Patterns
Creational Design Patterns
In plain words:
Creational patterns are focused towards how to instantiate an object or group of related objects.
Wikipedia says:
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.
🏠 Simple Factory
TODO
🏭 Factory Method
TODO
🔨 Abstract Factory
TODO
👷 Builder
TODO
🐑 Prototype
TODO
💍 Singleton
TODO
Structural Design Patterns
In plain words:
Structural patterns are mostly concerned with object composition or in other words how the entities can use each other. Or yet another explanation would be, they help in answering "How to build a software component?"
Wikipedia says:
In software engineering, structural design patterns are design patterns that ease the design by identifying a simple way to realize relationships between entities.
🔌 Adapter
TODO
🚡 Bridge
TODO
🌿 Composite
TODO
☕ Decorator
TODO
📦 Facade
TODO
🍃 Flyweight
TODO
🎱 Proxy
TODO
Behavioral Design Patterns
In plain words:
It is concerned with assignment of responsibilities between the objects. What makes them different from structural patterns is they don't just specify the structure but also outline the patterns for message passing/communication between them. Or in other words, they assist in answering "How to run a behavior in software component?"
Wikipedia says:
In software engineering, behavioral design patterns are design patterns that identify common communication patterns between objects and realize these patterns. By doing so, these patterns increase flexibility in carrying out this communication.
- Chain of Responsibility
- Command
- Iterator
- Mediator
- Memento
- Observer
- Visitor
- Strategy
- State
- Template Method
🔗 Chain of Responsibility
TODO
👮 Command
TODO
➿ Iterator
TODO
👽 Mediator
TODO
💾 Memento
TODO
😎 Observer
TODO
🏃 Visitor
TODO
💡 Strategy
TODO
💢 State
TODO
📒 Template Method
TODO
🚦 Wrap Up
And that about wraps it up. I will continue to improve this, so you might want to watch/star this repository to revisit. Also, I have plans on writing the same about the architectural patterns, stay tuned for it.
👬 Contribution
- Report issues
- Open pull request with improvements
- Spread the word
License
All content of this file, unless otherwise noted, is licensed as follows:
- All provided source code examples are covered by the MIT License.
- Other content, including images, is released under the Creative Common Attribution 4.0 International license.