Java by API/java.awt.event/ComponentAdapter

extends ComponentAdapter

   <source lang="java">

import java.awt.Dimension; import java.awt.Toolkit; import java.awt.event.ruponentAdapter; import java.awt.event.ruponentEvent; import javax.swing.JFrame; import javax.swing.JLabel;

class WindowSnapper extends ComponentAdapter {
 private boolean locked = false;
 private int sd = 50;
 public void componentMoved(ComponentEvent evt) {
   if (locked)
     return;
   Dimension size = Toolkit.getDefaultToolkit().getScreenSize();
   int nx = evt.getComponent().getX();
   int ny = evt.getComponent().getY();
   // top
   if (ny < 0 + sd) {
     ny = 0;
   }
   // left
   if (nx < 0 + sd) {
     nx = 0;
   }
   // right
   if (nx > size.getWidth() - evt.getComponent().getWidth() - sd) {
     nx = (int) size.getWidth() - evt.getComponent().getWidth();
   }
   // bottom
   if (ny > size.getHeight() - evt.getComponent().getHeight() - sd) {
     ny = (int) size.getHeight() - evt.getComponent().getHeight();
   }
   locked = true;
   evt.getComponent().setLocation(nx, ny);
   locked = false;
 }
 public static void main(String[] args) {
   JFrame frame = new JFrame("");
   JLabel label = new JLabel("Move this window"s title bar to demonstrate screen edge snapping.");
   frame.getContentPane().add(label);
   frame.pack();
   frame.addComponentListener(new WindowSnapper());
   frame.setVisible(true);
 }

}

 </source>