Java tutorial
/* * Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.sound.midi; /** * A {@code ShortMessage} contains a MIDI message that has at most two data * bytes following its status byte. The types of MIDI message that satisfy this * criterion are channel voice, channel mode, system common, and system * real-time--in other words, everything except system exclusive and * meta-events. The {@code ShortMessage} class provides methods for getting and * setting the contents of the MIDI message. * <p> * A number of {@code ShortMessage} methods have integer parameters by which you * specify a MIDI status or data byte. If you know the numeric value, you can * express it directly. For system common and system real-time messages, you can * often use the corresponding fields of {@code ShortMessage}, such as * {@link #SYSTEM_RESET SYSTEM_RESET}. For channel messages, the upper four bits * of the status byte are specified by a command value and the lower four bits * are specified by a MIDI channel number. To convert incoming MIDI data bytes * that are in the form of Java's signed bytes, you can use the * <a href="MidiMessage.html#integersVsBytes">conversion code</a> given in the * {@link MidiMessage} class description. * * @author David Rivas * @author Kara Kytle * @author Florian Bomers * @see SysexMessage * @see MetaMessage */ public class ShortMessage extends MidiMessage { // Status byte defines // System common messages /** * Status byte for MIDI Time Code Quarter Frame message (0xF1, or 241). * * @see MidiMessage#getStatus */ public static final int MIDI_TIME_CODE = 0xF1; // 241 /** * Status byte for Song Position Pointer message (0xF2, or 242). * * @see MidiMessage#getStatus */ public static final int SONG_POSITION_POINTER = 0xF2; // 242 /** * Status byte for MIDI Song Select message (0xF3, or 243). * * @see MidiMessage#getStatus */ public static final int SONG_SELECT = 0xF3; // 243 /** * Status byte for Tune Request message (0xF6, or 246). * * @see MidiMessage#getStatus */ public static final int TUNE_REQUEST = 0xF6; // 246 /** * Status byte for End of System Exclusive message (0xF7, or 247). * * @see MidiMessage#getStatus */ public static final int END_OF_EXCLUSIVE = 0xF7; // 247 // System real-time messages /** * Status byte for Timing Clock message (0xF8, or 248). * * @see MidiMessage#getStatus */ public static final int TIMING_CLOCK = 0xF8; // 248 /** * Status byte for Start message (0xFA, or 250). * * @see MidiMessage#getStatus */ public static final int START = 0xFA; // 250 /** * Status byte for Continue message (0xFB, or 251). * * @see MidiMessage#getStatus */ public static final int CONTINUE = 0xFB; // 251 /** * Status byte for Stop message (0xFC, or 252). * * @see MidiMessage#getStatus */ public static final int STOP = 0xFC; //252 /** * Status byte for Active Sensing message (0xFE, or 254). * * @see MidiMessage#getStatus */ public static final int ACTIVE_SENSING = 0xFE; // 254 /** * Status byte for System Reset message (0xFF, or 255). * * @see MidiMessage#getStatus */ public static final int SYSTEM_RESET = 0xFF; // 255 // Channel voice message upper nibble defines /** * Command value for Note Off message (0x80, or 128). */ public static final int NOTE_OFF = 0x80; // 128 /** * Command value for Note On message (0x90, or 144). */ public static final int NOTE_ON = 0x90; // 144 /** * Command value for Polyphonic Key Pressure (Aftertouch) message (0xA0, or * 160). */ public static final int POLY_PRESSURE = 0xA0; // 160 /** * Command value for Control Change message (0xB0, or 176). */ public static final int CONTROL_CHANGE = 0xB0; // 176 /** * Command value for Program Change message (0xC0, or 192). */ public static final int PROGRAM_CHANGE = 0xC0; // 192 /** * Command value for Channel Pressure (Aftertouch) message (0xD0, or 208). */ public static final int CHANNEL_PRESSURE = 0xD0; // 208 /** * Command value for Pitch Bend message (0xE0, or 224). */ public static final int PITCH_BEND = 0xE0; // 224 /** * Constructs a new {@code ShortMessage}. The contents of the new message * are guaranteed to specify a valid MIDI message. Subsequently, you may set * the contents of the message using one of the {@code setMessage} methods. * * @see #setMessage */ public ShortMessage() { this(new byte[3]); // Default message data: NOTE_ON on Channel 0 with max volume data[0] = (byte) (NOTE_ON & 0xFF); data[1] = (byte) 64; data[2] = (byte) 127; length = 3; } /** * Constructs a new {@code ShortMessage} which represents a MIDI message * that takes no data bytes. The contents of the message can be changed by * using one of the {@code setMessage} methods. * * @param status the MIDI status byte * @throws InvalidMidiDataException if {@code status} does not specify a * valid MIDI status byte for a message that requires no data bytes * @see #setMessage(int) * @see #setMessage(int, int, int) * @see #setMessage(int, int, int, int) * @see #getStatus() * @since 1.7 */ public ShortMessage(int status) throws InvalidMidiDataException { super(null); setMessage(status); // can throw InvalidMidiDataException } /** * Constructs a new {@code ShortMessage} which represents a MIDI message * that takes up to two data bytes. If the message only takes one data byte, * the second data byte is ignored. If the message does not take any data * bytes, both data bytes are ignored. The contents of the message can be * changed by using one of the {@code setMessage} methods. * * @param status the MIDI status byte * @param data1 the first data byte * @param data2 the second data byte * @throws InvalidMidiDataException if the status byte or all data bytes * belonging to the message do not specify a valid MIDI message * @see #setMessage(int) * @see #setMessage(int, int, int) * @see #setMessage(int, int, int, int) * @see #getStatus() * @see #getData1() * @see #getData2() * @since 1.7 */ public ShortMessage(int status, int data1, int data2) throws InvalidMidiDataException { super(null); setMessage(status, data1, data2); // can throw InvalidMidiDataException } /** * Constructs a new {@code ShortMessage} which represents a channel MIDI * message that takes up to two data bytes. If the message only takes one * data byte, the second data byte is ignored. If the message does not take * any data bytes, both data bytes are ignored. The contents of the message * can be changed by using one of the {@code setMessage} methods. * * @param command the MIDI command represented by this message * @param channel the channel associated with the message * @param data1 the first data byte * @param data2 the second data byte * @throws InvalidMidiDataException if the command value, channel value or * all data bytes belonging to the message do not specify a valid * MIDI message * @see #setMessage(int) * @see #setMessage(int, int, int) * @see #setMessage(int, int, int, int) * @see #getCommand() * @see #getChannel() * @see #getData1() * @see #getData2() * @since 1.7 */ public ShortMessage(int command, int channel, int data1, int data2) throws InvalidMidiDataException { super(null); setMessage(command, channel, data1, data2); } /** * Constructs a new {@code ShortMessage}. * * @param data an array of bytes containing the complete message. The * message data may be changed using the {@code setMessage} method. * @see #setMessage */ // $$fb this should throw an Exception in case of an illegal message! protected ShortMessage(byte[] data) { // $$fb this may set an invalid message. // Can't correct without compromising compatibility super(data); } /** * Sets the parameters for a MIDI message that takes no data bytes. * * @param status the MIDI status byte * @throws InvalidMidiDataException if {@code status} does not specify a * valid MIDI status byte for a message that requires no data bytes * @see #setMessage(int, int, int) * @see #setMessage(int, int, int, int) */ public void setMessage(int status) throws InvalidMidiDataException { // check for valid values int dataLength = getDataLength(status); // can throw InvalidMidiDataException if (dataLength != 0) { throw new InvalidMidiDataException( "Status byte; " + status + " requires " + dataLength + " data bytes"); } setMessage(status, 0, 0); } /** * Sets the parameters for a MIDI message that takes one or two data bytes. * If the message takes only one data byte, the second data byte is ignored; * if the message does not take any data bytes, both data bytes are ignored. * * @param status the MIDI status byte * @param data1 the first data byte * @param data2 the second data byte * @throws InvalidMidiDataException if the status byte, or all data bytes * belonging to the message, do not specify a valid MIDI message * @see #setMessage(int, int, int, int) * @see #setMessage(int) */ public void setMessage(int status, int data1, int data2) throws InvalidMidiDataException { // check for valid values int dataLength = getDataLength(status); // can throw InvalidMidiDataException if (dataLength > 0) { if (data1 < 0 || data1 > 127) { throw new InvalidMidiDataException("data1 out of range: " + data1); } if (dataLength > 1) { if (data2 < 0 || data2 > 127) { throw new InvalidMidiDataException("data2 out of range: " + data2); } } } // set the length length = dataLength + 1; // re-allocate array if ShortMessage(byte[]) constructor gave array with fewer elements if (data == null || data.length < length) { data = new byte[3]; } // set the data data[0] = (byte) (status & 0xFF); if (length > 1) { data[1] = (byte) (data1 & 0xFF); if (length > 2) { data[2] = (byte) (data2 & 0xFF); } } } /** * Sets the short message parameters for a channel message which takes up to * two data bytes. If the message only takes one data byte, the second data * byte is ignored; if the message does not take any data bytes, both data * bytes are ignored. * * @param command the MIDI command represented by this message * @param channel the channel associated with the message * @param data1 the first data byte * @param data2 the second data byte * @throws InvalidMidiDataException if the status byte or all data bytes * belonging to the message, do not specify a valid MIDI message * @see #setMessage(int, int, int) * @see #setMessage(int) * @see #getCommand * @see #getChannel * @see #getData1 * @see #getData2 */ public void setMessage(int command, int channel, int data1, int data2) throws InvalidMidiDataException { // check for valid values if (command >= 0xF0 || command < 0x80) { throw new InvalidMidiDataException("command out of range: 0x" + Integer.toHexString(command)); } if ((channel & 0xFFFFFFF0) != 0) { // <=> (channel<0 || channel>15) throw new InvalidMidiDataException("channel out of range: " + channel); } setMessage((command & 0xF0) | (channel & 0x0F), data1, data2); } /** * Obtains the MIDI channel associated with this event. This method assumes * that the event is a MIDI channel message; if not, the return value will * not be meaningful. * * @return MIDI channel associated with the message * @see #setMessage(int, int, int, int) */ public int getChannel() { // this returns 0 if an invalid message is set return (getStatus() & 0x0F); } /** * Obtains the MIDI command associated with this event. This method assumes * that the event is a MIDI channel message; if not, the return value will * not be meaningful. * * @return the MIDI command associated with this event * @see #setMessage(int, int, int, int) */ public int getCommand() { // this returns 0 if an invalid message is set return (getStatus() & 0xF0); } /** * Obtains the first data byte in the message. * * @return the value of the {@code data1} field * @see #setMessage(int, int, int) */ public int getData1() { if (length > 1) { return (data[1] & 0xFF); } return 0; } /** * Obtains the second data byte in the message. * * @return the value of the {@code data2} field * @see #setMessage(int, int, int) */ public int getData2() { if (length > 2) { return (data[2] & 0xFF); } return 0; } /** * Creates a new object of the same class and with the same contents as this * object. * * @return a clone of this instance */ @Override public Object clone() { byte[] newData = new byte[length]; System.arraycopy(data, 0, newData, 0, newData.length); return new ShortMessage(newData); } /** * Retrieves the number of data bytes associated with a particular status * byte value. * * @param status status byte value, which must represent a short MIDI * message * @return data length in bytes (0, 1, or 2) * @throws InvalidMidiDataException if the {@code status} argument does not * represent the status byte for any short message */ protected final int getDataLength(int status) throws InvalidMidiDataException { // system common and system real-time messages switch (status) { case 0xF6: // Tune Request case 0xF7: // EOX // System real-time messages case 0xF8: // Timing Clock case 0xF9: // Undefined case 0xFA: // Start case 0xFB: // Continue case 0xFC: // Stop case 0xFD: // Undefined case 0xFE: // Active Sensing case 0xFF: // System Reset return 0; case 0xF1: // MTC Quarter Frame case 0xF3: // Song Select return 1; case 0xF2: // Song Position Pointer return 2; default: } // channel voice and mode messages switch (status & 0xF0) { case 0x80: case 0x90: case 0xA0: case 0xB0: case 0xE0: return 2; case 0xC0: case 0xD0: return 1; default: throw new InvalidMidiDataException("Invalid status byte: " + status); } } }