content: /*
   * Copyright (C) 2006 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.os;
  
  import android.annotation.UnsupportedAppUsage;
  import android.os.Handler;
  import android.os.Message;
  
  import java.lang.ref.WeakReference;
  
  /** @hide */
  public class Registrant
  {
      @UnsupportedAppUsage
      public
      Registrant(Handler h, int what, Object obj)
      {
          refH = new WeakReference(h);
          this.what = what;
          userObj = obj;
      }
  
      @UnsupportedAppUsage
      public void
      clear()
      {
          refH = null;
          userObj = null;
      }
  
      @UnsupportedAppUsage
      public void
      notifyRegistrant()
      {
          internalNotifyRegistrant (null, null);
      }
      
      @UnsupportedAppUsage
      public void
      notifyResult(Object result)
      {
          internalNotifyRegistrant (result, null);
      }
  
      public void
      notifyException(Throwable exception)
      {
          internalNotifyRegistrant (null, exception);
      }
  
      /**
       * This makes a copy of @param ar
       */
      @UnsupportedAppUsage
      public void
      notifyRegistrant(AsyncResult ar)
      {
          internalNotifyRegistrant (ar.result, ar.exception);
      }
  
      /*package*/ void
      internalNotifyRegistrant (Object result, Throwable exception)
      {
          Handler h = getHandler();
  
          if (h == null) {
              clear();
          } else {
              Message msg = Message.obtain();
  
              msg.what = what;
              
              msg.obj = new AsyncResult(userObj, result, exception);
              
              h.sendMessage(msg);
          }
      }
  
      /**
       * NOTE: May return null if weak reference has been collected
       */
  
      @UnsupportedAppUsage
      public Message
      messageForRegistrant()
      {
          Handler h = getHandler();
  
          if (h == null) {
              clear();
  
              return null;
          } else {
              Message msg = h.obtainMessage();
  
              msg.what = what;
              msg.obj = userObj;
  
              return msg;
          }
      }
  
      public Handler
      getHandler()
      {
          if (refH == null)
              return null;
  
          return (Handler) refH.get();
      }
  
      WeakReference   refH;
      int             what;
      Object          userObj;
  }
  
  