LightIoC: Scala原生基于注解的依赖注入库

LightIoC是一个通过依赖注入的Scala轻量化控制反转工具，发布在GitHub上，项目地址。

添加依赖

Scala

这个库针对Scala 2.13.x, 2.12.x, 2.11.x进行编译，在Java8, 11, 16中通过测试。目前最新版本是0.3.0，请持续关注GitHub页面。

SBT:

1	libraryDependencies += "space.controlnet" %% "lightioc" % "0.3.0"

Gradle:

1	implementation group: "space.controlnet", name: "lightioc_<scala_version>", version: "0.3.0"

Java

这个库提供了一个Java友好的API，可以在Java中使用LightIoC。详情可以看Java API。

Gradle:

1	implementation group: "space.controlnet", name: "lightioc-api_2.13", version: "0.3.0"

快速开始

静态注册

import space.controlnet.lightioc.Container

@Provider 
class TopLevelClass

@Singleton
class TopLevelSingletonClass

@Provider(isObject = true)
object TopLevelObject

@Provider(stringId = "IdForThisClass")
class NamedProviderClass

@Provider(isObject = true)
object NestedClass {

  @Provider
  class InnerClass

  @Provider(isObject = true)
  object InnerObject
}

object Main extends App {
  Container.init("<package name>")
}

动态注册

import space.controlnet.lightioc.Container
import space.controlnet.lightioc.Util._

class Foo
class Bar {
  var x: Int = _
  var y: Int = _
}
object Baz
class Qux(foo: Foo)

object Main extends App {
  // register Foo to self constructor in Transient scope
  Container.register[Foo].toSelf.inTransientScope()
  // register Bar to self constructor in Singleton scope
  Container.register[Bar].toSelf.inSingletonScope()
  // register Baz as well
  Container.register[Baz.type].toSelf.inSingletonScope()
  // register a constructor with parameters
  Container.register[Qux].toConstructor(classOf[Foo]).inTransientScope()
  // register a constant value
  Container.register("A Number").toValue(123).inSingletonScope()
  // register a factory
  val barX = 1
  val barY = 2
  Container.register[Int]("Bar.x").toValue(barX).inSingletonScope()
  Container.register[Int]("Bar.y").toValue(barY).inSingletonScope()
  val factory: Factory[Bar] = Container => {
    // do anything you want
    val bar = new Bar
    bar.x = Container.resolve[Int]("Bar.x")
    bar.y = Container.resolve[Int]("Bar.y")
    bar
  }
  Container.register[Bar].toFactory(factory).inTransientScope()
  // register to another service (registry)
  Container.register[Foo].toSelf.inTransientScope() // target service
  Container.register("AnotherFoo").toService[Foo]
}

当然，也可以使用Scala特色的自定义运算符。

import space.controlnet.lightioc.Container
import space.controlnet.lightioc.BindingSetter.{ New, Self }

object Main extends App {
  // register to value in Transient
  Container.register("AString") -> "Hello IOC"
  // register to constructor/class in Transient
  Container.register[Foo] -> classOf[Foo]
  // register to constructor/class in Singleton
  Container.register[Bar] := classOf[Bar]
  // register to self
  Container.register[Baz.type] -> Self
  // register to a constructor with parameters
  Container.register[Qux] -> New(classOf[Foo])
  // register to factory
  Container.register[Bar] ~> factory
  // register to service
  Container.register("AnotherString") >> "AString"
}

动态获取

import space.controlnet.lightioc.Container

object Main extends App {
  // resolve by type
  val foo: Foo = Container.resolve[Foo]
  // resolve by string
  val str: String = Container.resolve[String]("AString")
  // resolve by factory
  val bar: Bar = Container.resolve[Bar]
}

自动装配

import space.controlnet.lightioc.annotation.{ Autowired, Provider }

@Provider
class Foo {
  @Autowired
  val bar: Bar = null
}

@Provider
class Bar

@Provider
object Baz {
  @Autowired
  var x: Int = 0 // should be "var"
}

Java API

一个使用Kotlin的例子。

import space.controlnet.lightioc.annotation.Singleton
import space.controlnet.lightioc.api.Container

@Singleton
class A {
    val x: Int = 100
}

fun main() {
    Container.init("<package name>")
    val a = Container.resolve(A::class.java)
    println(a.x)
}