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OldSong.java
106 lines (94 loc) · 3.05 KB
/
OldSong.java
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/*
* Copyright (C) 2000-2013 Heinz Max Kabutz
*
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership. Heinz Max Kabutz licenses
* this file to you 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 eu.javaspecialists.tjsn.examples.issue076;
import javax.sound.midi.*;
/**
* This class represents an Old Song that we might want to record
* for our listening pleasure.
*/
public abstract class OldSong {
private final Sequencer sequencer;
private final Track track;
private final int resolution;
private int pos;
/**
* @param key is the note that this starts with. 60 is middle C.
* @param tempo is measured in beats per second
*/
public OldSong(int key, int tempo, int resolution)
throws MidiUnavailableException,
InvalidMidiDataException {
this.resolution = resolution;
Sequence sequence = new Sequence(Sequence.PPQ, resolution);
track = sequence.createTrack();
makeSong(key);
sequencer = MidiSystem.getSequencer();
sequencer.open();
sequencer.setSequence(sequence);
sequencer.setTempoInBPM(tempo);
}
public void start() {
sequencer.start();
}
protected abstract void makeSong(int key)
throws InvalidMidiDataException;
protected void add(int note) throws InvalidMidiDataException {
add(note, 1);
}
protected synchronized void add(int note, int length)
throws InvalidMidiDataException {
addStartEvent(note);
pos += length;
addStopEvent(note);
}
protected synchronized void addSilence(int length) {
pos += length;
}
/**
* A piano teacher once told me that the first note in a bar
* should be emphasized.
* <p/>
* We assume that resolution has already been set and that we
* have the "this" monitor.
*/
private int volume() {
assert Thread.holdsLock(this);
assert pos != 0;
return ((pos % resolution) == 0) ? 100 : 70;
}
/**
* We assume that we are holding the "this" monitor
*/
private void addStartEvent(int note)
throws InvalidMidiDataException {
assert Thread.holdsLock(this);
ShortMessage message = new ShortMessage();
message.setMessage(ShortMessage.NOTE_ON, 0, note, volume());
track.add(new MidiEvent(message, pos));
}
/**
* We assume that we are holding the "this" monitor
*/
private void addStopEvent(int note)
throws InvalidMidiDataException {
assert Thread.holdsLock(this);
ShortMessage message = new ShortMessage();
message.setMessage(ShortMessage.NOTE_OFF, 0, note, 0);
track.add(new MidiEvent(message, pos));
}
}