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Dependency inversion principle
Definition
Dependency inversion principle
High-level modules should not depend on low-level modules.
Both should depend on abstractions (e.g. interfaces).
https://en.wikipedia.org/wiki/Dependency_inversion_principle
Definition
Dependency inversion principle
Abstractions should not depend on details.
Details (concrete implementations) should depend on abstractions.
https://en.wikipedia.org/wiki/Dependency_inversion_principle
High/Low level & boundary
Dependency inversion principle
https://clevercoder.net/2018/09/08/clean-architecture-summary-review/
The inversion
High/Low level & boundary
Dependency inversion principle
https://clevercoder.net/2018/09/08/clean-architecture-summary-review/
If the principle is applied, high-level classes are not affected by any changes to low-level classes.
In addition, high-level classes can be reused in any context that defines lower-level classes that implement an abstract interface defined in upper-level classes.
High/Low level & boundary
Dependency inversion principle
https://clevercoder.net/2018/09/08/clean-architecture-summary-review/
Less stable classes and components should depend on more stable ones, and not the other way around.
Clean Architecture
Dependency inversion principle
Clean Architecture: A Craftsman's Guide to Software Structure and Design
the most flexible systems are those in which ...
Source code dependencies refer only to abstractions, not to concretions.
Clean Architecture
Dependency inversion principle
Clean Architecture: A Craftsman's Guide to Software Structure and Design
more practically ...
Avoid to depend on volatility concrete factors.
The stable abstraction
Dependency inversion principle
Clean Architecture: A Craftsman's Guide to Software Structure and Design
Create Objects by Abstract Factory
#1
Only refer to abstraction interface,
The stable abstraction
Dependency inversion principle
Clean Architecture: A Craftsman's Guide to Software Structure and Design
Don't derive from volatile classes
#2
The stable abstraction
Dependency inversion principle
Clean Architecture: A Craftsman's Guide to Software Structure and Design
Don't override concrete methods
#3
It's bad inheritance.
Explain by Example
Dependency inversion principle
higher module depend on lower module
Explain by Example
Dependency inversion principle
Invert the dependency
Explain by Example
Dependency inversion principle
https://refactoring.guru/design-patterns/abstract-factory
Abstract Factory
Explain by Example
Dependency inversion principle
Further more... we can pass the dependency management to third party / system level.
Dependency inversion pattern generalization
Dependency inversion principle
Ioc - Inversion of Control
To decouple the execution of a task from implementation
“Hollywood Principle: Don’t call us, we’ll call you”.
Separate what-to-do and when-to-do
Dependency inversion pattern generalization
Dependency inversion principle
To decouple the execution of a task from implementation
To focus a module on the task it is designed for.
To free modules from assumptions about how other systems do what they do and instead rely on contracts.
To prevent side effects when replacing a module.
Dependency inversion pattern generalization
Dependency inversion principle
Passing the service to the client, rather than allowing a client to build or find the service, is the fundamental requirement of the pattern.
DI - Dependency Injection
IoC & DI in Framework
Dependency inversion principle
https://docs.nestjs.com/fundamentals/custom-providers
IoC & DI in Framework
Dependency inversion principle
https://docs.nestjs.com/fundamentals/custom-providers
IoC & DI in Framework
Dependency inversion principle
https://docs.nestjs.com/fundamentals/injection-scopes
Dependency inversion principle
IoC & DI in Framework
https://laravel.com/docs/7.x/container
In Infra Service Level
Dependency inversion principle
https://www.youtube.com/watch?v=gfh-VCTwMw8
In Infra Service Level
Dependency inversion principle
https://www.youtube.com/watch?v=gfh-VCTwMw8
In Infra Service Level
Dependency inversion principle
https://www.youtube.com/watch?v=gfh-VCTwMw8
Futher more ... CQRS
Search updating worker can listen on change event from Price service
Recursive Dependency -> SOA
Dependency inversion pattern generalization
Dependency inversion principle
https://en.wikipedia.org/wiki/Dependency_inversion_principle
Dependency inversion principle
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