!7

abstract sclass AbstractLayoutManager implements LayoutManager {
  Dimension preferredSize = new Dimension(100, 100);
  bool invalidate;

  public void addLayoutComponent(String name, Component comp) {
    print("addLayoutComponent called");
  }
  public void removeLayoutComponent(Component comp) {
    print("removeLayoutComponent called");
  }
  
  public Dimension preferredLayoutSize(Container parent) {
    print("preferredLayoutSize called (" + invalidate + ")");
    layoutContainer(parent);
    //validate(parent);
    ret preferredSize;
  }
  
  public Dimension minimumLayoutSize(Container parent) {
    print("minimumLayoutSize called");
    ret new Dimension(10, 10);
  }
  
  void validate(Container parent) {
    if (invalidate) {
      invalidate = false;
      layoutContainer(parent);
    }
  }
}

p-substance {
  JPanel panel = new JPanel(new AbstractLayoutManager {
    public void layoutContainer(Container parent) {
      Dimension size = parent.getSize();
      print("layoutContainer called, size=" + size);
      int y = 10;
      for (Component c : parent.getComponents()) {
        int h = c.getPreferredSize().height;
        c.setBounds(10, y, size.width-20, h);
        y += h + 10;
      }
      preferredSize = componentsBoundingSize(parent, 10);
    }
  });
  
  for i to 10:
    panel.add(jtextfield());
  print("components added");
    
  showFrame(panel);
}

Began life as a copy of #1008596