Introduction

We know that IOC(Inversion of Control) is an effective architectural design for system decoupling, and is also a supporting tool for the development of large-scale business systems

State Sharing: 4-in-1

In actual development, there are four scopes of state sharing: component internal, between components, global and system. In the traditional Vue3, different mechanisms are used to achieve these state sharing scopes, while only a unified IOC container mechanism is needed in Zova

Scope of state sharing	Traditional Vue3	Zova
Component internal	Composable	IOC
Between components	Provide/Inject	IOC
Global	Pinia	IOC
System	ES Module	IOC

Some people may ask, what is the difference between global state sharing and system state sharing?

Because in SSR scenarios, global state sharing is for each request, and system state sharing can cross requests

IOC Containers

There are three types of ioc containers in Zova:

1. sys container: During system initialization, a unique sys ioc container will be automatically created. Bean instances created in this container are all singleton mode
2. app container: When requests coming, the system will create a app container for each of them. The Bean instances created in this container are request-scoped singletons
3. ctx container: When creating Vue component instances, the system will create a ctx ioc container for each of them. Bean instances created in this container can share data and logic within the scope of the component instance

Bean Class

Zova adopts a modular system, and Bean Classes are provided by different modules

Injection Scope

Zova provides the following injection scopes:

1. sys: Inject in the sys container
2. app: Inject in the app container
3. ctx: Inject in the ctx container
4. new: Always create a new bean instance

Injection Scope: Hierarchical injection

The injection scope also supports hierarchical injection, replacing the capabilities of Vue3 Provide/Inject:

1. host: the bean instance will be lookuped in the ctx container of the current component instance and all parent containers in turn
2. skipSelf: lookup the bean instance in all parent containers in turn

Injection Methods

Zova provides two injection methods:

1. Dependency Injection: Provides property-based dependency injection through the @Use decorator
2. Dependency Lookup: Directly looks up the required bean instance through the ioc container, and automatically creates it if it does not exist