138 lines
4.9 KiB
Java
138 lines
4.9 KiB
Java
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.printservice.recommendation;
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import android.annotation.Nullable;
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import android.annotation.SystemApi;
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import android.app.Service;
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import android.content.Context;
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import android.content.Intent;
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import android.os.Handler;
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import android.os.IBinder;
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import android.os.Looper;
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import android.os.Message;
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import android.os.RemoteException;
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import android.util.Log;
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import java.util.List;
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/**
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* Base class for the print service recommendation services.
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*
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* @hide
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*/
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@SystemApi
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public abstract class RecommendationService extends Service {
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private static final String LOG_TAG = "PrintServiceRecS";
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/** Used to push onConnect and onDisconnect on the main thread */
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private Handler mHandler;
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/**
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* The {@link Intent} action that must be declared as handled by a service in its manifest for
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* the system to recognize it as a print service recommendation service.
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*/
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public static final String SERVICE_INTERFACE =
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"android.printservice.recommendation.RecommendationService";
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/** Registered callbacks, only modified on main thread */
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private IRecommendationServiceCallbacks mCallbacks;
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@Override
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protected void attachBaseContext(Context base) {
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super.attachBaseContext(base);
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mHandler = new MyHandler();
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}
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/**
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* Update the print service recommendations.
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*
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* @param recommendations The new set of recommendations
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*/
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public final void updateRecommendations(@Nullable List<RecommendationInfo> recommendations) {
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mHandler.obtainMessage(MyHandler.MSG_UPDATE, recommendations).sendToTarget();
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}
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@Override
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public final IBinder onBind(Intent intent) {
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return new IRecommendationService.Stub() {
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@Override
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public void registerCallbacks(IRecommendationServiceCallbacks callbacks) {
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// The callbacks come in order of the caller on oneway calls. Hence while the caller
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// cannot know at what time the connection is made, they can know the ordering of
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// connection and disconnection.
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//
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// Similar they cannot know when the disconnection is processed, hence they have to
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// handle callbacks after calling disconnect.
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if (callbacks != null) {
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mHandler.obtainMessage(MyHandler.MSG_CONNECT, callbacks).sendToTarget();
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} else {
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mHandler.obtainMessage(MyHandler.MSG_DISCONNECT).sendToTarget();
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}
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}
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};
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}
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/**
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* Called when the client connects to the recommendation service.
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*/
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public abstract void onConnected();
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/**
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* Called when the client disconnects from the recommendation service.
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*/
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public abstract void onDisconnected();
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private class MyHandler extends Handler {
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static final int MSG_CONNECT = 1;
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static final int MSG_DISCONNECT = 2;
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static final int MSG_UPDATE = 3;
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MyHandler() {
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super(Looper.getMainLooper());
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}
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@Override
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public void handleMessage(Message msg) {
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switch (msg.what) {
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case MSG_CONNECT:
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mCallbacks = (IRecommendationServiceCallbacks) msg.obj;
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onConnected();
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break;
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case MSG_DISCONNECT:
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onDisconnected();
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mCallbacks = null;
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break;
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case MSG_UPDATE:
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if (mCallbacks != null) {
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// Note that there might be a connection change in progress. In this case
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// the message is handled as before the change. This is acceptable as the
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// caller of the connection change has not guarantee when the connection
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// change binder transaction is actually processed.
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try {
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mCallbacks.onRecommendationsUpdated((List<RecommendationInfo>) msg.obj);
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} catch (RemoteException | NullPointerException e) {
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Log.e(LOG_TAG, "Could not update recommended services", e);
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}
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}
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break;
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}
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}
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}
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}
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