package patterns.headFirstDesignPatterns.combined.djview;
import java.util.ArrayList;
import javax.sound.midi.MetaEventListener;
import javax.sound.midi.MetaMessage;
import javax.sound.midi.MidiEvent;
import javax.sound.midi.MidiSystem;
import javax.sound.midi.Sequence;
import javax.sound.midi.Sequencer;
import javax.sound.midi.ShortMessage;
import javax.sound.midi.Track;
public class BeatModel implements BeatModelInterface, MetaEventListener {
Sequencer sequencer;
ArrayList beatObservers = new ArrayList();
ArrayList bpmObservers = new ArrayList();
int bpm = 90;
Sequence sequence;
Track track;
public void initialize() {
setUpMidi();
buildTrackAndStart();
}
public void on() {
sequencer.start();
setBPM(90);
}
public void off() {
setBPM(0);
sequencer.stop();
}
public void setBPM(int bpm) {
this.bpm = bpm;
sequencer.setTempoInBPM(getBPM());
notifyBPMObservers();
}
public int getBPM() {
return bpm;
}
void beatEvent() {
notifyBeatObservers();
}
public void registerObserver(BeatObserver o) {
beatObservers.add(o);
}
public void notifyBeatObservers() {
for(int i = 0; i < beatObservers.size(); i++) {
BeatObserver observer = (BeatObserver)beatObservers.get(i);
observer.updateBeat();
}
}
public void registerObserver(BPMObserver o) {
bpmObservers.add(o);
}
public void notifyBPMObservers() {
for(int i = 0; i < bpmObservers.size(); i++) {
BPMObserver observer = (BPMObserver)bpmObservers.get(i);
observer.updateBPM();
}
}
public void removeObserver(BeatObserver o) {
int i = beatObservers.indexOf(o);
if (i >= 0) {
beatObservers.remove(i);
}
}
public void removeObserver(BPMObserver o) {
int i = bpmObservers.indexOf(o);
if (i >= 0) {
bpmObservers.remove(i);
}
}
public void meta(MetaMessage message) {
if (message.getType() == 47) {
beatEvent();
sequencer.start();
setBPM(getBPM());
}
}
public void setUpMidi() {
try {
sequencer = MidiSystem.getSequencer();
sequencer.open();
sequencer.addMetaEventListener(this);
sequence = new Sequence(Sequence.PPQ,4);
track = sequence.createTrack();
sequencer.setTempoInBPM(getBPM());
} catch(Exception e) {
e.printStackTrace();
}
}
public void buildTrackAndStart() {
int[] trackList = {35, 0, 46, 0};
sequence.deleteTrack(null);
track = sequence.createTrack();
makeTracks(trackList);
track.add(makeEvent(192,9,1,0,4));
try {
sequencer.setSequence(sequence);
} catch(Exception e) {
e.printStackTrace();
}
}
public void makeTracks(int[] list) {
for (int i = 0; i < list.length; i++) {
int key = list[i];
if (key != 0) {
track.add(makeEvent(144,9,key, 100, i));
track.add(makeEvent(128,9,key, 100, i+1));
}
}
}
public MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) {
MidiEvent event = null;
try {
ShortMessage a = new ShortMessage();
a.setMessage(comd, chan, one, two);
event = new MidiEvent(a, tick);
} catch(Exception e) {
e.printStackTrace();
}
return event;
}
}