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 import java.util.HashMap; 24 25 /** @hide */ 26 public class Registrant 27 { 28 public Registrant(Handler h, int what, Object obj)29 Registrant(Handler h, int what, Object obj) 30 { 31 refH = new WeakReference(h); 32 this.what = what; 33 userObj = obj; 34 } 35 36 public void clear()37 clear() 38 { 39 refH = null; 40 userObj = null; 41 } 42 43 public void notifyRegistrant()44 notifyRegistrant() 45 { 46 internalNotifyRegistrant (null, null); 47 } 48 49 public void notifyResult(Object result)50 notifyResult(Object result) 51 { 52 internalNotifyRegistrant (result, null); 53 } 54 55 public void notifyException(Throwable exception)56 notifyException(Throwable exception) 57 { 58 internalNotifyRegistrant (null, exception); 59 } 60 61 /** 62 * This makes a copy of @param ar 63 */ 64 public void notifyRegistrant(AsyncResult ar)65 notifyRegistrant(AsyncResult ar) 66 { 67 internalNotifyRegistrant (ar.result, ar.exception); 68 } 69 70 /*package*/ void internalNotifyRegistrant(Object result, Throwable exception)71 internalNotifyRegistrant (Object result, Throwable exception) 72 { 73 Handler h = getHandler(); 74 75 if (h == null) { 76 clear(); 77 } else { 78 Message msg = Message.obtain(); 79 80 msg.what = what; 81 82 msg.obj = new AsyncResult(userObj, result, exception); 83 84 h.sendMessage(msg); 85 } 86 } 87 88 /** 89 * NOTE: May return null if weak reference has been collected 90 */ 91 92 public Message messageForRegistrant()93 messageForRegistrant() 94 { 95 Handler h = getHandler(); 96 97 if (h == null) { 98 clear(); 99 100 return null; 101 } else { 102 Message msg = h.obtainMessage(); 103 104 msg.what = what; 105 msg.obj = userObj; 106 107 return msg; 108 } 109 } 110 111 public Handler getHandler()112 getHandler() 113 { 114 if (refH == null) 115 return null; 116 117 return (Handler) refH.get(); 118 } 119 120 WeakReference refH; 121 int what; 122 Object userObj; 123 } 124 125