Communicating Between Threads

public class CakeMaker {

  /* Instance Variables */
  private boolean whiskInUse = false;
  private boolean ovenInUse = false;
  private boolean mixingBowlInUse = false;

  /* Main Method */
  public static void main(String[] args) {

    CakeMaker c = new CakeMaker();
    try {

      Thread preheatOven = new Thread(c::preheatOven, "preheatOven");
      Thread mixDryIngredients = new Thread(c::mixDryIngredients, "mixDryIngredients");
      Thread mixWetIngredients = new Thread(c::mixWetIngredients, "mixWetIngredients");
      Thread combineIngredients = new Thread(c::combineIngredients, "combineIngredients");
      Thread bakeCake = new Thread(c::bakeCake, "bakeCake");
      Thread makeFrosting = new Thread(c::makeFrosting, "makeFrosting");
      Thread frostCake = new Thread(c::frostCake, "frostCake");

      preheatOven.start();
      mixDryIngredients.start();
      mixWetIngredients.start();
      makeFrosting.start();
      mixDryIngredients.join();
      mixWetIngredients.join();
      combineIngredients.start();
      combineIngredients.join();
      preheatOven.join();
      bakeCake.start();
      makeFrosting.join();
      bakeCake.join();
      frostCake.start();
      frostCake.join();

      System.out.println("Cake complete!");
    } catch (Exception e) {
      System.out.println(e);
    }
  } // End of Main

  /* Instance Methods */
  public void preheatOven() {
    try {
      printTask("Oven pre-heating...");
      ovenInUse = true;
      Thread.sleep(10000);
      ovenInUse = false;
      printTask("Done!");
    } catch (InterruptedException e) {
      System.out.println(e);
    }
  }

  public void mixDryIngredients() {
    try {
      printTask("Mixing dry ingredients...");
      synchronized(this){
        while(mixingBowlInUse) {
          printTask("Waiting for the mixing bowl...");
          wait();}// Refactor to synchronize access to mixingBowlInUse
        printTask("Using mixing bowl!");
        mixingBowlInUse = true;}

      Thread.sleep(200);
      printTask("Adding cake flour");
      Thread.sleep(200);
      printTask("Adding salt");
      Thread.sleep(200);
      printTask("Adding baking powder");
      Thread.sleep(200);
      printTask("Adding baking soda");
      Thread.sleep(200);
      whiskInUse = true;
      printTask("Mixing...");
      Thread.sleep(200);
      whiskInUse = false;

      // Refactor to synchronize access to mixingBowlInUse
      mixingBowlInUse = false;
      printTask("Releasing mixing bowl!");
      notifyAll();

      printTask("Done!");
    } catch (InterruptedException e) {
      System.out.println(e);
    }
  };

  public void mixWetIngredients() {
    try {
      printTask("Mixing wet ingredients...");
      synchronized(this){
        while(mixingBowlInUse) {
          printTask("Waiting for the mixing bowl...");
          wait();}// Refactor to synchronize access to mixingBowlInUse
        printTask("Using mixing bowl!");
        mixingBowlInUse = true;}
      // Refactor to synchronize access to mixingBowlInUse



      Thread.sleep(1000);
      printTask("Adding butter...");
      Thread.sleep(500);
      printTask("Adding eggs...");
      Thread.sleep(500);
      printTask("Adding vanilla extract...");
      Thread.sleep(500);
      printTask("Adding buttermilk...");
      Thread.sleep(500);
      whiskInUse = true;
      printTask("Mixing...");
      Thread.sleep(1500);
      whiskInUse = false;

      // Refactor to synchronize access to mixingBowlInUse
      mixingBowlInUse = false;
      printTask("Releasing mixing bowl!");
      notifyAll();


      printTask("Done!");
    } catch (InterruptedException e) {
      System.out.println(e);
    }
  };

  public void combineIngredients() {
    try {
      printTask("Combining ingredients...");
      mixingBowlInUse = true;
      Thread.sleep(1000);
      printTask("Adding dry mix to wet mix...");
      Thread.sleep(1500);
      whiskInUse = true;
      printTask("Mixing...");
      Thread.sleep(1500);
      whiskInUse = false;
      mixingBowlInUse = false;
      printTask("Done!");
    } catch (InterruptedException e) {
      System.out.println(e);
    }
  };

  public void bakeCake() {
    try {
      printTask("Baking cake...");
      ovenInUse = true;
      Thread.sleep(10000);
      ovenInUse = false;
      printTask("Done!");
    } catch (InterruptedException e) {
      System.out.println(e);
    }
  }

  public void makeFrosting() {
    try {
      printTask("Making frosting...");
      whiskInUse = true;
      mixingBowlInUse = true;
      printTask("Adding butter...");
      Thread.sleep(200);
      printTask("Adding milk...");
      Thread.sleep(200);
      printTask("Adding sugar...");
      Thread.sleep(200);
      printTask("Adding vanilla extract...");
      Thread.sleep(200);
      printTask("Adding salt...");
      Thread.sleep(200);
      whiskInUse = false;
      mixingBowlInUse = false;
      printTask("Done!");

    } catch (InterruptedException e) {
      System.out.println(e);
    }
  }

  public void frostCake() {
    try {
      printTask("Frosting cake...");
      Thread.sleep(1500);
      printTask("Done!");

    } catch (InterruptedException e) {
      System.out.println(e);
    }
  }

  private void printTask(String task) {
    System.out.println(Thread.currentThread().getName() + " " + " - " + task);
  }
}