FlowGram.AI
Guide
Examples
Common APIs
API Documentation
Guide
Examples
Common APIs
API Documentation

IOC

Why is IOC needed?

Several concepts
  • Inversion of Control: Inversion of Control, a design principle in object - oriented programming, can be used to reduce the coupling between code modules. The most common way is called Dependency Injection (DI for short).
  • Domain Logic: Domain Logic, also known as Business Logic, is related to specific product features.
  • Aspect - Oriented Programming: AOP (Aspect - Oriented Programming). Its core design principle is to split the software system into multiple aspects (Aspect) of common logic (cross - cutting, with the meaning of penetration) and domain logic (vertical cutting). The cross - cutting part can be "consumed on demand" by all vertical - cutting parts.

Before answering this question, let's first understand aspect - oriented programming. The purpose of aspect - oriented programming is to split the granularity of domain logic into smaller parts. The cross - cutting part can be "consumed on demand" by the vertical - cutting part. The connection between the cross - cutting and vertical - cutting parts is also called weaving. And IOC plays the role of weaving and is injected into the vertical - cutting part.

Aspect - Oriented Programming

Ideal Aspect - Oriented Programming

- myAppliation provides business logic
  - service Specific business logic services
     - customDomainLogicService
  - contributionImplement Instantiation of hook registrations
    - MyApplicationContributionImpl
  - component Business components

- core provides common logic
  - model Common models
  - contribution Hook interfaces
     - LifecycleContribution Application lifecycle
     - CommandContribution
  - service Common service services
     - CommandService
     - ClipboardService
  - component Common components
// IOC injection
@injectable()
export class CustomDomainLogicService {
@inject(FlowContextService) protected flowContextService: FlowContextService;
@inject(CommandService) protected commandService: CommandService;
@inject(SelectionService) protected selectionService: SelectionService;
}
// IOC interface declaration
interface LifecycleContribution {
 onInit(): void
 onStart(): void
 onDispose(): void
}
// IOC interface implementation
@injectable()
export class MyApplicationContributionImpl implements LifecycleContribution {
  onStart(): void {
    // Specific business logic code
  }
}

// Manually attach to the lifecycle hook
bind(LifecycleContribution).toService(MyApplicationContributionImpl)
IOC is an aspect-oriented programming technique, after the introduction, the underlying module can be exposed to the interface in the form of the external registration, which brings the following benefits:
  • Implement a micro - kernel + plug - in design to achieve plug - and - play and on - demand consumption of plug - ins.
  • Allow the package to be split more cleanly and achieve feature - based package splitting.