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
17package com.android.printservice.recommendation;
18
19import android.annotation.IntRange;
20import android.annotation.NonNull;
21import 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 */
30public 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