p.
  <span class="location-badge">exported from <a href="/angular2/di_annotations">angular2/di_annotations</a></span>
  defined in <a href="https://github.com/angular/angular/tree/master/modules/angular2/src/di/annotations.js#L110">angular2/src/di/annotations.js (line 110)</a>

:markdown
  `DependencyAnnotation` is used by the framework to extend DI.
  
  Only annotations implementing `DependencyAnnotation` are 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.
  
.l-main-section
  h2 Members
  .l-sub-section
    h3 constructor

    
    pre.prettyprint
      code.
        constructor()
    
    :markdown
      




  .l-sub-section
    h3 token

    
    :markdown