1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.os; 18 19 import android.os.Handler; 20 import android.os.Message; 21 22 import java.lang.ref.WeakReference; 23 24 /** @hide */ 25 public class Registrant 26 { 27 public Registrant(Handler h, int what, Object obj)28 Registrant(Handler h, int what, Object obj) 29 { 30 refH = new WeakReference(h); 31 this.what = what; 32 userObj = obj; 33 } 34 35 public void clear()36 clear() 37 { 38 refH = null; 39 userObj = null; 40 } 41 42 public void notifyRegistrant()43 notifyRegistrant() 44 { 45 internalNotifyRegistrant (null, null); 46 } 47 48 public void notifyResult(Object result)49 notifyResult(Object result) 50 { 51 internalNotifyRegistrant (result, null); 52 } 53 54 public void notifyException(Throwable exception)55 notifyException(Throwable exception) 56 { 57 internalNotifyRegistrant (null, exception); 58 } 59 60 /** 61 * This makes a copy of @param ar 62 */ 63 public void notifyRegistrant(AsyncResult ar)64 notifyRegistrant(AsyncResult ar) 65 { 66 internalNotifyRegistrant (ar.result, ar.exception); 67 } 68 69 /*package*/ void internalNotifyRegistrant(Object result, Throwable exception)70 internalNotifyRegistrant (Object result, Throwable exception) 71 { 72 Handler h = getHandler(); 73 74 if (h == null) { 75 clear(); 76 } else { 77 Message msg = Message.obtain(); 78 79 msg.what = what; 80 81 msg.obj = new AsyncResult(userObj, result, exception); 82 83 h.sendMessage(msg); 84 } 85 } 86 87 /** 88 * NOTE: May return null if weak reference has been collected 89 */ 90 91 public Message messageForRegistrant()92 messageForRegistrant() 93 { 94 Handler h = getHandler(); 95 96 if (h == null) { 97 clear(); 98 99 return null; 100 } else { 101 Message msg = h.obtainMessage(); 102 103 msg.what = what; 104 msg.obj = userObj; 105 106 return msg; 107 } 108 } 109 110 public Handler getHandler()111 getHandler() 112 { 113 if (refH == null) 114 return null; 115 116 return (Handler) refH.get(); 117 } 118 119 WeakReference refH; 120 int what; 121 Object userObj; 122 } 123 124