The very first object-oriented language I learned when I was 19 in my computer science & engineering program at school. I had my professor Jeff Meunier teaching us through making projects which, looking back, was the best way that he could have taught us Java to be honest. It was and still is an incredibly verbose language but at the end we made a cool project with a music beat to it. I struggled with it before but I wonder how well I would do at it now. 


This was the main part of the code that I was really stoked that I figured out. Looking back i don't really know why...

```java
public Chord(Sound[] sounds)

{ super(sounds.length);

 int _subIndex = 0; f

or(int n=_subIndex ; n<sounds.length; n++) 

{ SoundPlayer sp = new SoundPlayer(); 

this.subscribe(sp); } }

```

  

Recommended reading in the Murach book:

312, 318-321, 

  

#### Steps for the old java synthesizer assignment

  

1. Create new project, named CSE1102-HW06-Rhythminator1
    

  

2. Create new `Main` class, with normal main method 
    

  

3. Create a new package called `message`. 
    

Make a `IPublisher` and `ISubscriber` class/interface

- In IPublisher interface copy&paste:
    
```java
public interface IPublisher

{

 public void subscribe(ISubscriber subscriber);

 public void unsubscribe(ISubscriber subscriber);

}

```


- In ISubscriber interface copy&paste:
    
```java
public interface ISubscriber

{

 public void notify(Message msg);

}



```

  

4. Create `Broadcaster` class in the message package implementing:
    

```
public class Broadcaster implements IPublisher, ISubscriber

```


There will be redlines and therefore right click to automatically correct

Create a constructor:

```java
public Broadcaster(int max_subscribers){

int [ ] array = _iSubscriberholder;

array = null;

 }

Make private member variable outside of constructor at the top:

private int[ ] _iSubscriberholder

```
  

5. Creating the subscribe method in the Broadcaster class
    

```java
private int x = 0;

@Override

public void subscribe(ISubscriber subscriber){

[x++] = subscriber;}


```

  

6. Create the same unsubscribe method as in lab, except without body if java doesn’t already do it for you 
    

  

7. copy&paste the publish method essentially and change method name to notify
    

  

8. Make comment blocks for each public method in the Broadcaster class
    

example:

```java
/**

 * Broadcasts a message to multiple subscribers.

 */

public class Broadcaster implements IPublisher, ISubscriber

This is the comment block for the constructor:

/**

 * Creates an instance of a Broadcaster that can hold up to some number of

 * subscribers.

 * @param numSubscribers The maximum number of subscribers that this11

 * Broadcaster can hold.

 */

public Broadcaster(int numSubscribers)


```


  

9. Create a class called TestSubscriber in the message package. Copy&paste:
    

```java

package message;

public class TestSubscriber implements ISubscriber

{

 private String _name;

 public TestSubscriber(String name)

 {

 _name = name;

 }

 @Override

 public void notify(Message msg)

 {

 System.out.println("TestSubscriber notified, name = " + _name);

 }

 public static void main(String[] args)

 {

 Broadcaster b = new Broadcaster(4);

 b.subscribe(new TestSubscriber("first"));

 b.subscribe(new TestSubscriber("second"));

 b.subscribe(new TestSubscriber("third"));

 b.subscribe(new TestSubscriber("fourth"));

 b.notify(null); // we'll use a null message for now

 }

}

```

  
  

If you run it, it SHOULD look like this in the output:

```

TestSubscriber notified, name = first

TestSubscriber notified, name = second

TestSubscriber notified, name = third

TestSubscriber notified, name = fourth

```

  
  

10.  change to this for testing purposes:
    


```java
Broadcaster b = new Broadcaster(4);

b.subscribe(new TestSubscriber("first"));

b.subscribe(new TestSubscriber("second"));

b.notify(null); // we'll use a null message for now

error!
```


to fix: don’t call notify method on null array location 

  
  

11.  Copy&Paste `Broadcaster`class and rename as `Sequencer`
    

  

12.  Change the `notify` method so that it looks like this:
    

```java
int y = 0;

method:

public void notify(){

if(array = null){???}
```
create private member variable first: 

furthermore fix the sequncermuch like above so that it works if any/all of array location are null

  

this should be the output if it works:

```
TestSubscriber notified, name = first

TestSubscriber notified, name = second

TestSubscriber notified, name = first

TestSubscriber notified, name = second

```

  
  

13.  make comments for each public method 
    

  

14. create a new package called model
    

  

15.  Make a new class called `Clock`  in model package , download class file from website and paste code into the class
    

  

16.  add javadoc comments like before
    

  

17.  Create a `TestClock` class in the model package with main method:
    

code should look like this:

```java
public static void main(String[] args)

{

 Clock c = new Clock();

 TestSubscriber ts = new TestSubscriber("clock tick");

 c.subscribe(ts);

 c.start(8);

}

  

```


output should be this (8 times, once every half second):

``TestSubscriber notified, name = clock tick``

  

replace the TestSubscriber in the main method with a Sequencer, but then put a few TestSubscriber instances in the sequencer. Have the sequencer subscribe to the clock. Run it!

  

output should be this:

```
TestSubscriber notified, name = first

TestSubscriber notified, name = second

TestSubscriber notified, name = third

TestSubscriber notified, name = fourth

TestSubscriber notified, name = first

TestSubscriber notified, name = second

TestSubscriber notified, name = third

TestSubscriber notified, name = fourth

```

  
  
  

18.   Download sounds.zip file from website, make a new folder inside the project called sounds. Unzip zip file and drag and drop the sound bytes into the folder
    

  

19.  Download Sound.java file and place it inside the model package
    

  

20.  Create a class called `Sound`  and paste this (you should hear sound after running and you can choose which sounds to put in ):
    
```
public class TestSound

{

 public static void main(String[] args)

 {

 Sound.scanSoundDir();

 Sound s1 = new Sound("DrumRhythm1");

 s1.play();

 }

}



```

  

21.  Create a class called `SoundPlayer`
    

22.  make it implements the ISubscriber interface
    

  

23.  let Eclipse create the notify method in the class
    

  

24.  create a constructor with String parameter:
    
```
public Sound _name;

public SoundPlayer(String x){

_name = new Sound (x);

}

```


25.  create another constructor with Sound parameter:
    

```java

pubic SoundPlayer(Sound y){

y = _name;

```

  

26. inside the notify method, play the sound?
    

  

27.  Create `TestSoundPlayer` class in model package, and copy&paste this:
    

```java
public static void main(String[] args)

{

 Sound.scanSoundDir();

 SoundPlayer drum = new SoundPlayer("KickDrum6");

 SoundPlayer fizz = new SoundPlayer("Fizz");

 Sequencer seq = new Sequencer(8);

 seq.subscribe(drum); // step 1

 seq.subscribe(drum); // step 219

 seq.subscribe(fizz); // step 3

 seq.subscribe(drum); // step 4

 seq.subscribe(drum); // step 5

 seq.subscribe(drum); // step 6

 seq.subscribe(fizz); // step 7

 seq.subscribe(null); // step 8 is a rest

 Clock c = new Clock();

 c.setDelay(250);

 c.subscribe(seq);

 c.start(16);

}


```


  

28.  create comments for this class (SoundPlayer)
    
29. Create Chord class that extends Broadcaster class
    

  

30.  create a constructor like this:
    

```java 
 public Chord(Sound[ ] x){

super(sounds.length);}

  


```

  

31.   
    

Inside the Chord constructor, below that statement, do this: create a new SoundPlayer for 

each of the sounds in the parameter array. Have that SoundPlayer subscribe to this 

instance. lolwut?

It works like this:


```java

for(some loop)

{

 SoundPlayer sp = new SoundPlayer(___);

 this.subscribe(sp);

}


```

  
  

32.  Test it in the main method now
    

Here's the main method:

f

You should hear all three sounds played at the same time

  
  

33.  comment everything in the chord class
    

  

34. create a `SoundBank` class in the model package
    

  

35.  Give this class a constructor that has a Sound array parameter and stores that array in a member var iable.
    

```java 

Sound [ ] _soundbanks;

SoundBank(Sound[ ] y){

y = _soundbanks;}

```

  
  

36.  ?????????????????? HOW DO YOU WRITE THIS METHOD?
    

  

37.  TestSoundBank 
    

```java 

public static void main(String[] args)

{

 Sound.scanSoundDir();

 Sound s1 = new Sound("Glockenspiel1");

 Sound s2 = new Sound("Snare1");

 Sound s3 = new Sound("BassDrum1");

 SoundBank sb = new SoundBank(new Sound[]{s1, s2, s3});

 Chord c = sb.chord(new boolean[]{true, true, true});

 c.notify(null);

}
```


Also make sure that this works:
```java

Chord c = sb.chord(new int[]{0, 1, 2});
```


  

38.  Test this in the main class:
    

```java

public static void main(String[] args)

 {

 Sound.scanSoundDir();

 Sound s1 = new Sound("Tom1");

 Sound s2 = new Sound("Fizz");

 Sound s3 = new Sound("NintendoCore1");

 Sound s4 = new Sound("NintendoCore2");

 Sound s5 = new Sound("Snare4");

 Sound s6 = new Sound("KickDrum5");

 SoundBank sb = new SoundBank(new Sound[]{s1, s2, s3, s4, s5, s6});

 Sequencer seq = new Sequencer(16);

 seq.subscribe(sb.chord(new int[]{2, 5})); // 1

 seq.subscribe(sb.chord(new int[]{5})); // 2

 seq.subscribe(sb.chord(new int[]{4})); // 3

 seq.subscribe(sb.chord(new int[]{1})); // 4

 seq.subscribe(sb.chord(new int[]{2, 4})); // 5

 seq.subscribe(sb.chord(new int[]{0})); // 6

 seq.subscribe(sb.chord(new int[]{4})); // 7

 seq.subscribe(sb.chord(new int[]{0, 5})); // 8

 seq.subscribe(sb.chord(new int[]{3, 5})); // 9

 seq.subscribe(sb.chord(new int[]{4})); // 10

 seq.subscribe(sb.chord(new int[]{1})); // 11

 seq.subscribe(sb.chord(new int[]{4})); // 12

 seq.subscribe(sb.chord(new int[]{0, 3, 4})); // 134

 seq.subscribe(sb.chord(new int[]{0})); // 14

 seq.subscribe(sb.chord(new int[]{4})); // 15

 seq.subscribe(sb.chord(new int[]{0, 1})); // 16

 Clock c = new Clock();

 c.setDelay(250);

 c.subscribe(seq);

 c.start(32);

 }

```

  

It should work, sequence of 16 beats that repeats twice 

  

39.  delete classes
    

Delete these classes:

• message package: TestSubscriber

• model package: TestChord, TestClock, TestSound, TestSoundBank, TestSoundPlayer

  

40.