Class DaggerApplication

java/dagger/android/DaggerApplication.java:35–122

An Application that injects its members and can be used to inject Activitys, Fragments, Services, BroadcastReceivers and ContentProviders attached to it. Injection is performed in #onCreate() or the first call to {@link AndroidInjection#inject(

 * AndroidInjection#inject(ContentProvider)}, whichever happens first.
 */
@Beta
public abstract class DaggerApplication extends Application
    implements HasActivityInjector,
        HasFragmentInjector,
        HasServiceInjector,
        HasBroadcastReceiverInjector,
        HasContentProviderInjector {

  @Inject DispatchingAndroidInjector<Activity> activityInjector;
  @Inject DispatchingAndroidInjector<BroadcastReceiver> broadcastReceiverInjector;
  @Inject DispatchingAndroidInjector<Fragment> fragmentInjector;
  @Inject DispatchingAndroidInjector<Service> serviceInjector;
  @Inject DispatchingAndroidInjector<ContentProvider> contentProviderInjector;
  private volatile boolean needToInject = true;

  @Override
  public void onCreate() {
    super.onCreate();
    injectIfNecessary();
  }

  /**
   * Implementations should return an {@link AndroidInjector} for the concrete {@link
   * DaggerApplication}. Typically, that injector is a {@link dagger.Component}.
   */
  @ForOverride
  protected abstract AndroidInjector<? extends DaggerApplication> applicationInjector();

  /**
   * Lazily injects the {@link DaggerApplication}'s members. Injection cannot be performed in {@link
   * Application#onCreate()} since {@link android.content.ContentProvider}s' {@link
   * android.content.ContentProvider#onCreate() onCreate()} method will be called first and might
   * need injected members on the application. Injection is not performed in the constructor, as
   * that may result in members-injection methods being called before the constructor has completed,
   * allowing for a partially-constructed instance to escape.
   */
  private void injectIfNecessary() {
    if (needToInject) {
      synchronized (this) {
        if (needToInject) {
          @SuppressWarnings("unchecked")
          AndroidInjector<DaggerApplication> applicationInjector =
              (AndroidInjector<DaggerApplication>) applicationInjector();
          applicationInjector.inject(this);
          if (needToInject) {
            throw new IllegalStateException(
                "The AndroidInjector returned from applicationInjector() did not inject the "
                    + "DaggerApplication");
          }
        }
      }
    }
  }

  @Inject
  void setInjected() {
    needToInject = false;
  }