1 /* 2 * Copyright (C) 2016 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 com.android.printservice.recommendation; 18 19 import android.annotation.IntRange; 20 import android.annotation.NonNull; 21 import android.annotation.StringRes; 22 23 /** 24 * Interface to be implemented by each print service plugin. 25 * <p/> 26 * A print service plugin is a minimal version of a real {@link android.printservice.PrintService 27 * print service}. You cannot print using the plugin. The only functionality in the plugin is to 28 * report the number of printers that the real service would discover. 29 */ 30 public interface PrintServicePlugin { 31 /** 32 * Call back used by the print service plugins. 33 */ 34 interface PrinterDiscoveryCallback { 35 /** 36 * Announce that something changed and the UI for this plugin should be updated. 37 * 38 * @param numDiscoveredPrinters The number of printers discovered. 39 */ 40 void onChanged(@IntRange(from = 0) int numDiscoveredPrinters); 41 } 42 43 /** 44 * Get the name (a string reference) of the {@link android.printservice.PrintService print 45 * service} with the {@link #getPackageName specified package name}. This is read once, hence 46 * returning different data at different times is not allowed. 47 * 48 * @return The name of the print service as a string reference. The localization is handled 49 * outside of the plugin. 50 */ 51 @StringRes int getName(); 52 53 /** 54 * The package name of the full print service. 55 * 56 * @return The package name 57 */ 58 @NonNull CharSequence getPackageName(); 59 60 /** 61 * Start the discovery plugin. 62 * 63 * @param callback Callbacks used by this plugin. 64 * 65 * @throws Exception If anything went wrong when starting the plugin 66 */ 67 void start(@NonNull PrinterDiscoveryCallback callback) throws Exception; 68 69 /** 70 * Stop the plugin. This can only return once the plugin is completely finished and cleaned up. 71 * 72 * @throws Exception If anything went wrong while stopping plugin 73 */ 74 void stop() throws Exception; 75 } 76