| /* |
| * Copyright (C) 2016 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.printservice.recommendation; |
| |
| import android.annotation.Nullable; |
| import android.annotation.SystemApi; |
| import android.app.Service; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.os.Handler; |
| import android.os.IBinder; |
| import android.os.Looper; |
| import android.os.Message; |
| import android.os.RemoteException; |
| import android.util.Log; |
| |
| import java.util.List; |
| |
| /** |
| * Base class for the print service recommendation services. |
| * |
| * @hide |
| */ |
| @SystemApi |
| public abstract class RecommendationService extends Service { |
| private static final String LOG_TAG = "PrintServiceRecS"; |
| |
| /** Used to push onConnect and onDisconnect on the main thread */ |
| private Handler mHandler; |
| |
| /** |
| * The {@link Intent} action that must be declared as handled by a service in its manifest for |
| * the system to recognize it as a print service recommendation service. |
| */ |
| public static final String SERVICE_INTERFACE = |
| "android.printservice.recommendation.RecommendationService"; |
| |
| /** Registered callbacks, only modified on main thread */ |
| private IRecommendationServiceCallbacks mCallbacks; |
| |
| @Override |
| protected void attachBaseContext(Context base) { |
| super.attachBaseContext(base); |
| |
| mHandler = new MyHandler(); |
| } |
| |
| /** |
| * Update the print service recommendations. |
| * |
| * @param recommendations The new set of recommendations |
| */ |
| public final void updateRecommendations(@Nullable List<RecommendationInfo> recommendations) { |
| mHandler.obtainMessage(MyHandler.MSG_UPDATE, recommendations).sendToTarget(); |
| } |
| |
| @Override |
| public final IBinder onBind(Intent intent) { |
| return new IRecommendationService.Stub() { |
| @Override |
| public void registerCallbacks(IRecommendationServiceCallbacks callbacks) { |
| // The callbacks come in order of the caller on oneway calls. Hence while the caller |
| // cannot know at what time the connection is made, he can know the ordering of |
| // connection and disconnection. |
| // |
| // Similar he cannot know when the disconnection is processed, hence he has to |
| // handle callbacks after calling disconnect. |
| if (callbacks != null) { |
| mHandler.obtainMessage(MyHandler.MSG_CONNECT, callbacks).sendToTarget(); |
| } else { |
| mHandler.obtainMessage(MyHandler.MSG_DISCONNECT).sendToTarget(); |
| } |
| } |
| }; |
| } |
| |
| /** |
| * Called when the client connects to the recommendation service. |
| */ |
| public abstract void onConnected(); |
| |
| /** |
| * Called when the client disconnects from the recommendation service. |
| */ |
| public abstract void onDisconnected(); |
| |
| private class MyHandler extends Handler { |
| static final int MSG_CONNECT = 1; |
| static final int MSG_DISCONNECT = 2; |
| static final int MSG_UPDATE = 3; |
| |
| MyHandler() { |
| super(Looper.getMainLooper()); |
| } |
| |
| @Override |
| public void handleMessage(Message msg) { |
| switch (msg.what) { |
| case MSG_CONNECT: |
| mCallbacks = (IRecommendationServiceCallbacks) msg.obj; |
| onConnected(); |
| break; |
| case MSG_DISCONNECT: |
| onDisconnected(); |
| mCallbacks = null; |
| break; |
| case MSG_UPDATE: |
| // Note that there might be a connection change in progress. In this case the |
| // message is handled as before the change. This is acceptable as the caller of |
| // the connection change has not guarantee when the connection change binder |
| // transaction is actually processed. |
| try { |
| mCallbacks.onRecommendationsUpdated((List<RecommendationInfo>) msg.obj); |
| } catch (RemoteException | NullPointerException e) { |
| Log.e(LOG_TAG, "Could not update recommended services", e); |
| } |
| break; |
| } |
| } |
| } |
| } |