problem of override setLocation of java.awt.Component

[Mandar Khire]

I create swing program which has 1 JFrame which contain 1 JPanel which contain n no of small JPanels.

When small JPanel set Location i try 2 ways
1st way is as follows:-

import java.awt.*;
import java.util.*;
import javax.swing.*;
class Testing1 {
	final int NUMBER_OF_PANELS = 1;
	int k, j = 30;
	int sys_resolution_x, sys_resolution_y;
	JPanel holdingPanel1 = new JPanel(); 
	Point defalut_location;
	JFrame f = new JFrame();
	DraggerPanel dp;
	int number;
	java.util.List<DraggerPanel> panelList = new ArrayList<DraggerPanel>();
	boolean isOverlapping;	
    public void buildGUI() {
		GraphicsEnvironment myenv = GraphicsEnvironment.getLocalGraphicsEnvironment();
		sys_resolution_x = myenv.getMaximumWindowBounds().width;
		sys_resolution_y = myenv.getMaximumWindowBounds().height;
		f.setLocation(sys_resolution_x, sys_resolution_y);
		f.setPreferredSize(new Dimension(sys_resolution_x-10, sys_resolution_y-10));
		f.setMaximumSize(new Dimension(sys_resolution_x-10, sys_resolution_y-10));
		holdingPanel1.setPreferredSize(new Dimension(f.getX() - 50,	f.getY() -50));
		holdingPanel1.setBorder(BorderFactory.createLineBorder(Color.BLACK, 1));
		for (int x = 0; x < NUMBER_OF_PANELS; x++){
			dp = new DraggerPanel(panelList, x);
			panelList.add(dp);
			holdingPanel1.setLayout(null);
			holdingPanel1.add(dp);
		}
		f.setExtendedState(f.getExtendedState() | Frame.MAXIMIZED_BOTH);
		f.getContentPane().add(holdingPanel1);
		f.pack();
		f.setLocationRelativeTo(null);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.pack();
			f.setVisible(true);
	}
	public static void main(String[] args) {
		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				new Testing1().buildGUI();
			}
		});
	}
	public class DraggerPanel extends JPanel {
		private static final long serialVersionUID = 1L;
		java.util.List<DraggerPanel> panels;
		Rectangle overlapZone;
		Rectangle draggableZone; 
		int index;
		public DraggerPanel(java.util.List<DraggerPanel> panelList, int index) {
			panels = panelList;
			this.index = index;
			setBackground(new Color(255, 255, 204));
			setSize(25, 25);
			defalut_location = new Point((30 + (30 * k)), ((j)));
			k++;
			setLocation(defalut_location);
                        System.out.println("Here finally set location");
			setBorder(BorderFactory.createLineBorder(Color.black, 1));
			setName(String.valueOf(index));
		}

		@Override
		public void setLocation(int x, int y) {
		  System.out.println("testing1 setlocation");
			Dimension dim = getSize();
			overlapZone = new Rectangle(x - dim.width, y - dim.height,dim.width * 2, dim.height * 2);
			isOverlapping = checkOverlap(new Point(x, y)); // x & y are
			if (isOverlapping) {
//				System.out.println("isOverlapping ="+isOverlapping);
				setLocation(x + 25, y);// only moves 25 to the right                             
				 System.out.println("testing1 setlocation1");
			} else {
				System.out.println("isOverlapping ="+isOverlapping);
				super.setLocation(x, y);
				 System.out.println("testing1 setlocation2");
			}
		}
		public boolean checkOverlap(Point pt) {
			for (int x = 0, y = panels.size(); x < y; x++) {
				if (x != index) {
					DraggerPanel dp = panels.get(x);
					if (dp.overlapZone.contains(pt)) {
						return true;
					}
				}
			}
			return false;
		}
		@Override
		protected void paintComponent(Graphics g) {
			try {
				super.paintComponent(g);
			} catch (Exception e) {
				e.printStackTrace();
			}
			g.drawString(String.valueOf(index), 10, 17);
		}
	}
}

and another way is
I declare Point mandarlocation;
& following code replace in above code's setLocation function

		@Override
		public void setLocation(Point location) {
                    try {
//  System.out.println("testing1 setlocation");
			} catch (Exception e) {
				e.printStackTrace();
			}
			Dimension dim = getSize();
			overlapZone = new Rectangle(location.x - dim.width, location.y - dim.height,dim.width * 2, dim.height * 2);
			isOverlapping = checkOverlap(new Point(location.x, location.y)); // x & y are
			if (isOverlapping) {
				System.out.println("isOverlapping ="+isOverlapping);
                                mandarlocation = new Point(location.x + 25, location.y);
                                System.out.println("1mandarlocation = "+mandarlocation);
                                try {
                                    setLocation(mandarlocation);
			} catch (Exception e) {
				e.printStackTrace();
			}                  

			} else {
				System.out.println("isOverlapping ="+isOverlapping);
                            try {
 mandarlocation = new Point(location.x, location.y);
  setLocation(mandarlocation);
			} catch (StackOverflowError e) {
				e.printStackTrace();
			}
			}
		}

So by first way i get very properly result, but when i run 2nd way i got exception stack overflow.
By first way from java.awt.component small JPanel set Location.

/**
* Moves this component to a new location. The top-left corner of
* the new location is specified by the <code>x</code> and <code>y</code>
* parameters in the coordinate space of this component's parent.
* @param x the x-coordinate of the new location's
* top-left corner in the parent's coordinate space
* @param y the y-coordinate of the new location's
* top-left corner in the parent's coordinate space
* @see #getLocation
* @see #setBounds
* @since JDK1.1
*/
public void setLocation(int x, int y) {
move(x, y);
}
/**
* @deprecated As of JDK version 1.1,
* replaced by <code>setLocation(int, int)</code>.
*/
@Deprecated
public void move(int x, int y) {
synchronized(getTreeLock()) {
setBoundsOp(ComponentPeer.SET_LOCATION);
setBounds(x, y, width, height);
}
}

but when i run 2nd way then almost 2500 times it run setLocation function within a program not going in to the java.awt.Component
Can anybody help me to understand why this so?

[Tony Docherty]

Because in the second example when the panels are not overlapping you recursively call the setLocation() method rather than calling the super.setLocation() method.