1 /* 2 * Copyright (C) 2015 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.example.android.common.midi; 18 19 import android.media.midi.MidiReceiver; 20 import android.media.midi.MidiSender; 21 22 import java.io.IOException; 23 import java.util.concurrent.CopyOnWriteArrayList; 24 25 /** 26 * Utility class for dispatching MIDI data to a list of {@link MidiReceiver}s. 27 * This class subclasses {@link MidiReceiver} and dispatches any data it receives 28 * to its receiver list. Any receivers that throw an exception upon receiving data will 29 * be automatically removed from the receiver list, but no IOException will be returned 30 * from the dispatcher's {@link MidiReceiver#onReceive} in that case. 31 */ 32 public final class MidiDispatcher extends MidiReceiver { 33 34 private final CopyOnWriteArrayList<MidiReceiver> mReceivers 35 = new CopyOnWriteArrayList<MidiReceiver>(); 36 37 private final MidiSender mSender = new MidiSender() { 38 /** 39 * Called to connect a {@link MidiReceiver} to the sender 40 * 41 * @param receiver the receiver to connect 42 */ 43 @Override 44 public void onConnect(MidiReceiver receiver) { 45 mReceivers.add(receiver); 46 } 47 48 /** 49 * Called to disconnect a {@link MidiReceiver} from the sender 50 * 51 * @param receiver the receiver to disconnect 52 */ 53 @Override 54 public void onDisconnect(MidiReceiver receiver) { 55 mReceivers.remove(receiver); 56 } 57 }; 58 59 /** 60 * Returns the number of {@link MidiReceiver}s this dispatcher contains. 61 * @return the number of receivers 62 */ 63 public int getReceiverCount() { 64 return mReceivers.size(); 65 } 66 67 /** 68 * Returns a {@link MidiSender} which is used to add and remove 69 * {@link MidiReceiver}s 70 * to the dispatcher's receiver list. 71 * @return the dispatcher's MidiSender 72 */ 73 public MidiSender getSender() { 74 return mSender; 75 } 76 77 @Override 78 public void onSend(byte[] msg, int offset, int count, long timestamp) throws IOException { 79 for (MidiReceiver receiver : mReceivers) { 80 try { 81 receiver.send(msg, offset, count, timestamp); 82 } catch (IOException e) { 83 // if the receiver fails we remove the receiver but do not propagate the exception 84 mReceivers.remove(receiver); 85 } 86 } 87 } 88 89 @Override 90 public void flush() throws IOException { 91 for (MidiReceiver receiver : mReceivers) { 92 receiver.flush(); 93 } 94 } 95 } 96
