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          */
onChanged(@ntRangefrom = 0) int numDiscoveredPrinters)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      */
getName()51     @StringRes int getName();
52 
53     /**
54      * The package name of the full print service.
55      *
56      * @return The package name
57      */
getPackageName()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      */
start(@onNull PrinterDiscoveryCallback callback)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      */
stop()74     void stop() throws Exception;
75 }
76