angular-cn/modules/di/src/annotations.js

import {CONST} from "facade/lang";

/**
 * A parameter annotation that creates a synchronous eager dependency.
 *
 *    class AComponent {
 *      constructor(@Inject('aServiceToken') aService) {}
 *    }
 *
 */
export class Inject {
  @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 {
  @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 {
  @CONST()
  constructor(token) {
    this.token = token;
  }
}

/**
 * `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() {
  }
}