1/*
2 * Copyright (C) 2012 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 android.media;
18
19/**
20 * The MediaSyncEvent class defines events that can be used to synchronize playback or capture
21 * actions between different players and recorders.
22 * <p>For instance, {@link AudioRecord#startRecording(MediaSyncEvent)} is used to start capture
23 * only when the playback on a particular audio session is complete.
24 * The audio session ID is retrieved from a player (e.g {@link MediaPlayer}, {@link AudioTrack} or
25 * {@link ToneGenerator}) by use of the getAudioSessionId() method.
26 */
27public class MediaSyncEvent {
28
29    /**
30     * No sync event specified. When used with a synchronized playback or capture method, the
31     * behavior is equivalent to calling the corresponding non synchronized method.
32     */
33    public static final int SYNC_EVENT_NONE = AudioSystem.SYNC_EVENT_NONE;
34
35    /**
36     * The corresponding action is triggered only when the presentation is completed
37     * (meaning the media has been presented to the user) on the specified session.
38     * A synchronization of this type requires a source audio session ID to be set via
39     * {@link #setAudioSessionId(int) method.
40     */
41    public static final int SYNC_EVENT_PRESENTATION_COMPLETE =
42                                                    AudioSystem.SYNC_EVENT_PRESENTATION_COMPLETE;
43
44
45    /**
46     * Creates a synchronization event of the sepcified type.
47     *
48     * <p>The type specifies which kind of event is monitored.
49     * For instance, event {@link #SYNC_EVENT_PRESENTATION_COMPLETE} corresponds to the audio being
50     * presented to the user on a particular audio session.
51     * @param eventType the synchronization event type.
52     * @return the MediaSyncEvent created.
53     * @throws java.lang.IllegalArgumentException
54     */
55    public static MediaSyncEvent createEvent(int eventType)
56                            throws IllegalArgumentException {
57        if (!isValidType(eventType)) {
58            throw (new IllegalArgumentException(eventType
59                    + "is not a valid MediaSyncEvent type."));
60        } else {
61            return new MediaSyncEvent(eventType);
62        }
63    }
64
65    private final int mType;
66    private int mAudioSession = 0;
67
68    private MediaSyncEvent(int eventType) {
69        mType = eventType;
70    }
71
72    /**
73     * Sets the event source audio session ID.
74     *
75     * <p>The audio session ID specifies on which audio session the synchronization event should be
76     * monitored.
77     * It is mandatory for certain event types (e.g. {@link #SYNC_EVENT_PRESENTATION_COMPLETE}).
78     * For instance, the audio session ID can be retrieved via
79     * {@link MediaPlayer#getAudioSessionId()} when monitoring an event on a particular MediaPlayer.
80     * @param audioSessionId the audio session ID of the event source being monitored.
81     * @return the MediaSyncEvent the method is called on.
82     * @throws java.lang.IllegalArgumentException
83     */
84    public MediaSyncEvent setAudioSessionId(int audioSessionId)
85            throws IllegalArgumentException {
86        if (audioSessionId > 0) {
87            mAudioSession = audioSessionId;
88        } else {
89            throw (new IllegalArgumentException(audioSessionId + " is not a valid session ID."));
90        }
91        return this;
92    }
93
94    /**
95     * Gets the synchronization event type.
96     *
97     * @return the synchronization event type.
98     */
99    public int getType() {
100        return mType;
101    }
102
103    /**
104     * Gets the synchronization event audio session ID.
105     *
106     * @return the synchronization audio session ID. The returned audio session ID is 0 if it has
107     * not been set.
108     */
109    public int getAudioSessionId() {
110        return mAudioSession;
111    }
112
113    private static boolean isValidType(int type) {
114        switch (type) {
115        case SYNC_EVENT_NONE:
116        case SYNC_EVENT_PRESENTATION_COMPLETE:
117            return true;
118        default:
119            return false;
120        }
121    }
122}
123