import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class Resizing extends Applet  {

public void init() 
{
	setBackground(Color.yellow);
	PoliteFrame frame = new PoliteFrame("A frame");
	PanelWithBars panelWithBars = new PanelWithBars();
	frame.add(panelWithBars);
	frame.setBounds(300, 100, 400, 550); 
	frame.validate();
	frame.show();
}
}  // END OF Class Resizing


class PanelWithBars extends Panel {

int barsShowing, maxBars, barHeight, pad;
Bar[] bar;

PanelWithBars()
{
	setLayout(new GridBagLayout());
	barsShowing = maxBars = 4;
	barHeight = 100;
	pad = 5;
	bar = new Bar[maxBars]; 
	for (int i=0; i<maxBars; i++)
	{
		bar[i] = new Bar(barHeight);
		addBar(i);
	}
}

public void setBounds(int x, int y, int width, int height)
{
	int barsToShow = height/(barHeight + pad + pad);
	if (barsToShow > maxBars) barsToShow = maxBars;
	if (barsToShow < barsShowing) for (int i = barsToShow; i<barsShowing; i++) remove(bar[i]);
	else if (barsToShow > barsShowing) for (int i = barsShowing; i<barsToShow; i++) addBar(i);
	barsShowing = barsToShow;
	super.setBounds(x, y, width, height);
}

void addBar(int index)
{
	constrain(this, bar[index], 0, index, 1, 1, GridBagConstraints.NORTH, pad, pad, pad, pad, 
		GridBagConstraints.NONE, 0, 0);
}

static final void constrain(Container container, Component component, int grid_x, int grid_y, 
		int grid_width, int grid_height, int anchor, int topPad, int leftPad, int bottomPad, 
		int rightPad, int fill, double weightx, double weighty)
{
	GridBagConstraints c = new GridBagConstraints();
	c.gridx = grid_x;
	c.gridy = grid_y;
	c.gridwidth = grid_width;
	c.gridheight = grid_height;
	c.anchor = anchor;
	c.insets.top   = topPad;
	c.insets.left  = leftPad;
	c.insets.bottom= bottomPad;
	c.insets.right = rightPad;
	c.fill = fill;
	c.weightx = weightx;
	c.weighty = weighty;
	((GridBagLayout)container.getLayout()).setConstraints(component, c);
	container.add(component);
}
}  //  END OF Class PanelWithBars


class PoliteFrame extends Frame implements WindowListener
{
	
PoliteFrame(String s)
{
	super(s);
	addWindowListener(this);
}

public void windowOpened(WindowEvent we){}

public void windowClosed(WindowEvent we){}

public void windowIconified(WindowEvent we){}

public void windowDeiconified(WindowEvent we){}

public void windowActivated(WindowEvent we){}

public void windowDeactivated(WindowEvent we){}

public void windowClosing(WindowEvent we)
{
	if (we.getSource() == this)
	{
		setVisible(false);
		dispose();
	}
}
}  //  END OF Class PoliteFrame



final class Bar extends Canvas  {

int width;
int height;

Bar(int height)
{
	this.height	= height;
}

public void addNotify()
{
	super.addNotify();
	repaint();
}

public final void paint(Graphics g)
{
	width = getSize().width;
	g.setColor(Color.blue);
	g.fillRect(0, 0, width, height);
}	

public final Dimension getMinimumSize()
{
	return(new Dimension(10, height));
}

public final Dimension getPreferredSize()
{
	return(new Dimension(300, height));
}
}  // END OF Class Bar