1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.internal.midi;
import android.media.midi.MidiReceiver;
import android.media.midi.MidiSender;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* Utility class for dispatching MIDI data to a list of {@link android.media.midi.MidiReceiver}s.
* This class subclasses {@link android.media.midi.MidiReceiver} and dispatches any data it receives
* to its receiver list. Any receivers that throw an exception upon receiving data will
* be automatically removed from the receiver list. If a MidiReceiverFailureHandler has been
* provided to the MidiDispatcher, it will be notified about the failure, but the exception
* itself will be swallowed.
*/
public final class MidiDispatcher extends MidiReceiver {
// MidiDispatcher's client and MidiReceiver's owner can be different
// classes (e.g. MidiDeviceService is a client, but MidiDeviceServer is
// the owner), and errors occuring during sending need to be reported
// to the owner rather than to the sender.
//
// Note that the callbacks will be called on the sender's thread.
public interface MidiReceiverFailureHandler {
void onReceiverFailure(MidiReceiver receiver, IOException failure);
}
private final MidiReceiverFailureHandler mFailureHandler;
private final CopyOnWriteArrayList<MidiReceiver> mReceivers
= new CopyOnWriteArrayList<MidiReceiver>();
private final MidiSender mSender = new MidiSender() {
@Override
public void onConnect(MidiReceiver receiver) {
mReceivers.add(receiver);
}
@Override
public void onDisconnect(MidiReceiver receiver) {
mReceivers.remove(receiver);
}
};
public MidiDispatcher() {
this(null);
}
public MidiDispatcher(MidiReceiverFailureHandler failureHandler) {
mFailureHandler = failureHandler;
}
/**
* Returns the number of {@link android.media.midi.MidiReceiver}s this dispatcher contains.
* @return the number of receivers
*/
public int getReceiverCount() {
return mReceivers.size();
}
/**
* Returns a {@link android.media.midi.MidiSender} which is used to add and remove
* {@link android.media.midi.MidiReceiver}s
* to the dispatcher's receiver list.
* @return the dispatcher's MidiSender
*/
public MidiSender getSender() {
return mSender;
}
@Override
public void onSend(byte[] msg, int offset, int count, long timestamp) throws IOException {
for (MidiReceiver receiver : mReceivers) {
try {
receiver.send(msg, offset, count, timestamp);
} catch (IOException e) {
// If the receiver fails we remove the receiver but do not propagate the exception.
// Note that this may also happen if the client code stalls, and thus underlying
// MidiInputPort.onSend has raised IOException for EAGAIN / EWOULDBLOCK error.
mReceivers.remove(receiver);
if (mFailureHandler != null) {
mFailureHandler.onReceiverFailure(receiver, e);
}
}
}
}
@Override
public void onFlush() throws IOException {
for (MidiReceiver receiver : mReceivers) {
try {
receiver.flush();
} catch (IOException e) {
// This is just a special case of 'send' thus handle in the same way.
mReceivers.remove(receiver);
if (mFailureHandler != null) {
mFailureHandler.onReceiverFailure(receiver, e);
}
}
}
}
}
|
