| /* |
| * Copyright (C) 2014 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 android.media.midi; |
| |
| import java.io.IOException; |
| |
| /** |
| * Interface for sending and receiving data to and from a MIDI device. |
| */ |
| abstract public class MidiReceiver { |
| |
| private final int mMaxMessageSize; |
| |
| /** |
| * Default MidiReceiver constructor. Maximum message size is set to |
| * {@link java.lang.Integer#MAX_VALUE} |
| */ |
| public MidiReceiver() { |
| mMaxMessageSize = Integer.MAX_VALUE; |
| } |
| |
| /** |
| * MidiReceiver constructor. |
| * @param maxMessageSize the maximum size of a message this receiver can receive |
| */ |
| public MidiReceiver(int maxMessageSize) { |
| mMaxMessageSize = maxMessageSize; |
| } |
| |
| /** |
| * Called whenever the receiver is passed new MIDI data. |
| * Subclasses override this method to receive MIDI data. |
| * May fail if count exceeds {@link #getMaxMessageSize}. |
| * |
| * NOTE: the msg array parameter is only valid within the context of this call. |
| * The msg bytes should be copied by the receiver rather than retaining a reference |
| * to this parameter. |
| * Also, modifying the contents of the msg array parameter may result in other receivers |
| * in the same application receiving incorrect values in their {link #onSend} method. |
| * |
| * @param msg a byte array containing the MIDI data |
| * @param offset the offset of the first byte of the data in the array to be processed |
| * @param count the number of bytes of MIDI data in the array to be processed |
| * @param timestamp the timestamp of the message (based on {@link java.lang.System#nanoTime} |
| * @throws IOException |
| */ |
| abstract public void onSend(byte[] msg, int offset, int count, long timestamp) |
| throws IOException; |
| |
| /** |
| * Instructs the receiver to discard all pending MIDI data. |
| * @throws IOException |
| */ |
| public void flush() throws IOException { |
| onFlush(); |
| } |
| |
| /** |
| * Called when the receiver is instructed to discard all pending MIDI data. |
| * Subclasses should override this method if they maintain a list or queue of MIDI data |
| * to be processed in the future. |
| * @throws IOException |
| */ |
| public void onFlush() throws IOException { |
| } |
| |
| /** |
| * Returns the maximum size of a message this receiver can receive. |
| * @return maximum message size |
| */ |
| public final int getMaxMessageSize() { |
| return mMaxMessageSize; |
| } |
| |
| /** |
| * Called to send MIDI data to the receiver without a timestamp. |
| * Data will be processed by receiver in the order sent. |
| * Data will get split into multiple calls to {@link #onSend} if count exceeds |
| * {@link #getMaxMessageSize}. Blocks until all the data is sent or an exception occurs. |
| * In the latter case, the amount of data sent prior to the exception is not provided to caller. |
| * The communication should be considered corrupt. The sender should reestablish |
| * communication, reset all controllers and send all notes off. |
| * |
| * @param msg a byte array containing the MIDI data |
| * @param offset the offset of the first byte of the data in the array to be sent |
| * @param count the number of bytes of MIDI data in the array to be sent |
| * @throws IOException if the data could not be sent in entirety |
| */ |
| public void send(byte[] msg, int offset, int count) throws IOException { |
| // TODO add public static final TIMESTAMP_NONE = 0L |
| send(msg, offset, count, 0L); |
| } |
| |
| /** |
| * Called to send MIDI data to the receiver with a specified timestamp. |
| * Data will be processed by receiver in order first by timestamp, then in the order sent. |
| * Data will get split into multiple calls to {@link #onSend} if count exceeds |
| * {@link #getMaxMessageSize}. Blocks until all the data is sent or an exception occurs. |
| * In the latter case, the amount of data sent prior to the exception is not provided to caller. |
| * The communication should be considered corrupt. The sender should reestablish |
| * communication, reset all controllers and send all notes off. |
| * |
| * @param msg a byte array containing the MIDI data |
| * @param offset the offset of the first byte of the data in the array to be sent |
| * @param count the number of bytes of MIDI data in the array to be sent |
| * @param timestamp the timestamp of the message, based on {@link java.lang.System#nanoTime} |
| * @throws IOException if the data could not be sent in entirety |
| */ |
| public void send(byte[] msg, int offset, int count, long timestamp) |
| throws IOException { |
| int messageSize = getMaxMessageSize(); |
| while (count > 0) { |
| int length = (count > messageSize ? messageSize : count); |
| onSend(msg, offset, length, timestamp); |
| offset += length; |
| count -= length; |
| } |
| } |
| } |