content: /*
   * 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.example.android.common.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 MidiReceiver}s.
   * This class subclasses {@link 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, but no IOException will be returned
   * from the dispatcher's {@link MidiReceiver#onReceive} in that case.
   */
  public final class MidiDispatcher extends MidiReceiver {
  
      private final CopyOnWriteArrayList<MidiReceiver> mReceivers
              = new CopyOnWriteArrayList<MidiReceiver>();
  
      private final MidiSender mSender = new MidiSender() {
          /**
           * Called to connect a {@link MidiReceiver} to the sender
           *
           * @param receiver the receiver to connect
           */
          @Override
          public void onConnect(MidiReceiver receiver) {
              mReceivers.add(receiver);
          }
  
          /**
           * Called to disconnect a {@link MidiReceiver} from the sender
           *
           * @param receiver the receiver to disconnect
           */
          @Override
          public void onDisconnect(MidiReceiver receiver) {
              mReceivers.remove(receiver);
          }
      };
  
      /**
       * Returns the number of {@link MidiReceiver}s this dispatcher contains.
       * @return the number of receivers
       */
      public int getReceiverCount() {
          return mReceivers.size();
      }
  
      /**
       * Returns a {@link MidiSender} which is used to add and remove
       * {@link 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
                  mReceivers.remove(receiver);
              }
          }
      }
  
      @Override
      public void flush() throws IOException {
         for (MidiReceiver receiver : mReceivers) {
              receiver.flush();
         }
      }
  }
  