Show the given frame as modal to the specified owner : SwingUtilities « Swing « Java Tutorial

1. Java Tutorial
2. Swing
3. SwingUtilities

import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import javax.swing.JFrame;

// @author Santhosh Kumar T - santhosh@in.fiorano.com 
public class ModalFrameUtil {
  static class EventPump implements InvocationHandler {
    Frame frame;

    public EventPump(Frame frame) {
      this.frame = frame;
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
      return frame.isShowing();
    }

    // when the reflection calls in this method has to be
    // replaced once Sun provides a public API to pump events.
    public void start() throws Exception {
      Class<?> clazz = Class.forName("java.awt.Conditional");
      Object conditional = Proxy.newProxyInstance(clazz.getClassLoader(), new Class[] { clazz },
          this);
      Method pumpMethod = Class.forName("java.awt.EventDispatchThread").getDeclaredMethod(
          "pumpEvents", new Class[] { clazz });
      pumpMethod.setAccessible(true);
      pumpMethod.invoke(Thread.currentThread(), new Object[] { conditional });
    }
  }

  // show the given frame as modal to the specified owner.
  // NOTE: this method returns only after the modal frame is closed.
  public static void showAsModal(final Frame frame, final Frame owner) {
    frame.addWindowListener(new WindowAdapter() {
      public void windowOpened(WindowEvent e) {
        owner.setEnabled(false);
      }

      public void windowClosing(WindowEvent e) {
        owner.setEnabled(true);
        frame.removeWindowListener(this);
      }

      public void windowClosed(WindowEvent e) {
        owner.setEnabled(true);
        frame.removeWindowListener(this);
      }
    });

    owner.addWindowListener(new WindowAdapter() {
      public void windowActivated(WindowEvent e) {
        if (frame.isShowing()) {
          frame.setExtendedState(JFrame.NORMAL);
          frame.toFront();
        } else {
          owner.removeWindowListener(this);
        }
      }
    });

    frame.setVisible(true);
    try {
      new EventPump(frame).start();
    } catch (Throwable throwable) {
      throw new RuntimeException(throwable);
    }
  }
}