How do you choose what class you add to a list with a variable?

Processing Coding Questions
#1

So I want to do something like this, where you add a new instance of a class determined by a variable (trust me, I have a good reason for this, but I can’t tell…)

Class type;
dummy1 list[] = new dummy1[3];

void setup() {
  type = dummy2.class;
  list[0] = new type;
  type = dummy3.class;
  list[1] = new type;
}

class dummy1 {}

class dummy2 extends dummy1 {}

class dummy3 extends dummy1 {}

This (obviously) doesn’t work… I am wondering if there is a different correct way to do this. Apologies if the answer is easy and I am just dumb

#2

Please format your code:

#3 
// https://Discourse.Processing.org/t/
// how-do-you-choose-what-class-you-add-to-a-list-with-a-variable/22987/3

// GoToLoop (2020/Aug/02)

static final int DUMB = 0, DUMMY = 1, DUMBER = 2;
int dumbType;

void draw() {
  dumbType = (int) random(3);
  final Dumb d = getDumb(dumbType);
  print(d, TAB);

  noLoop();
  background((color) random(#000000));
}

void mousePressed() {
  redraw();
}

Dumb getDumb(final int which) {
  switch (which) {
  case DUMB: 
    return new Dumb();
  case DUMMY: 
    return new Dummy();
  case DUMBER:
    return new Dumber();
  default: 
    throw new RuntimeException("Unknown Dumb Type Value!");
  }
}

class Dumb {
  @Override String toString() {
    return getClass().getSimpleName();
  }
}

class Dummy extends Dumb {
}

class Dumber extends Dumb {
}
#4

@GoToLoop This is a valid answer, (I had thought of this myself) but I want to avoid having a big switch statement. My question was kind of vague, but to clarify I have a lot of classes, and don’t want to do this, but I will if I have to.

#5

You can replace that w/ Class::getDeclaredConstructor() + Constructor::newInstance(): :construction:

  1. Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Class.html#getDeclaredConstructor(java.lang.Class...)
  2. Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/lang/reflect/Constructor.html#newInstance(java.lang.Object...)

I’m basing this new alternative version from these 2 old forum threads: :thread:

  1. Forum.Processing.org/two/discussion/27164/string-to-class-classnotfoundexception#Item_5
  2. Discourse.Processing.org/t/solved-instantiating-a-particular-class-constructor-using-reflection/7968
// https://Discourse.Processing.org/t/
// how-do-you-choose-what-class-you-add-to-a-list-with-a-variable/22987/5

// GoToLoop (2020/Aug/02)

static final Class[] dumbClasses = {
  Dumb.class, Dummy.class, Dumber.class
};

final Class<? extends PApplet> sketchClass = getClass();

void draw() {
  final Class<Dumb> dumbClass = dumbClasses[(int) random(dumbClasses.length)];
  final Dumb d = getDumb(dumbClass);
  print(d, TAB);

  noLoop();
  background((color) random(#000000));
}

void mousePressed() {
  redraw();
}

<T> T getDumb(final Class<T> dumbClass) {
  try {
    return dumbClass.getDeclaredConstructor(sketchClass).newInstance(this);
  }
  catch (final ReflectiveOperationException e) {
    System.err.println(e);
    return null;
  }
}

class Dumb {
  @Override String toString() {
    return getClass().getSimpleName();
  }
}

class Dummy extends Dumb {
}

class Dumber extends Dumb {
}