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Angular-Docs-Cn/modules/angular2/src/di/annotations.js
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import {CONST} from "angular2/src/facade/lang";
/**
* A parameter annotation that creates a synchronous eager dependency.
*
* ```
* class AComponent {
* constructor(@Inject('aServiceToken') aService) {}
* }
* ```
*
*/
export class Inject {
token;
@CONST()
constructor(token) {
this.token = token;
}
}
/**
* A parameter annotation that creates an asynchronous eager dependency.
*
* ```
* class AComponent {
* constructor(@InjectPromise('aServiceToken') aServicePromise) {
* aServicePromise.then(aService => ...);
* }
* }
* ```
*
*/
export class InjectPromise {
token;
@CONST()
constructor(token) {
this.token = token;
}
}
/**
* A parameter annotation that creates a synchronous lazy dependency.
*
* ```
* class AComponent {
* constructor(@InjectLazy('aServiceToken') aServiceFn) {
* aService = aServiceFn();
* }
* }
* ```
*
*/
export class InjectLazy {
token;
@CONST()
constructor(token) {
this.token = token;
}
}
/**
* A parameter annotation that marks a dependency as optional.
*
* ```
* class AComponent {
* constructor(@Optional() dp:Dependency) {
* this.dp = dp;
* }
* }
* ```
*
*/
export class Optional {
@CONST()
constructor() {
}
}
/**
* `DependencyAnnotation` is used by the framework to extend DI.
*
* Only annotations implementing `DependencyAnnotation` will be added
* to the list of dependency properties.
*
* For example:
*
* ```
* class Parent extends DependencyAnnotation {}
* class NotDependencyProperty {}
*
* class AComponent {
* constructor(@Parent @NotDependencyProperty aService:AService) {}
* }
* ```
*
* will create the following dependency:
*
* ```
* new Dependency(Key.get(AService), [new Parent()])
* ```
*
* The framework can use `new Parent()` to handle the `aService` dependency
* in a specific way.
*
*/
export class DependencyAnnotation {
@CONST()
constructor() {
}
}