/* class EnumWinApplet for IE browsers uses J/Direct with an inner class callback
    to enumerate top level windows using EnumWindows() API call. Also demonstrates
    closing a user-selected window using SendMessage() function

					M. Gallant   05/01/2002 */

import java.awt.*;
import com.ms.security.*;
import com.ms.wfc.util.*;
import com.ms.win32.win;
import java.awt.event.*;

public class EnumWinApplet extends java.applet.Applet implements ActionListener{
 private StringBuffer strb;
 private TextArea ta = new TextArea(15, 80) ;
 private Button closewindow = new Button("Close Window") ;
 private Button cleartext = new Button("Clear") ;
 private Button updatewins = new Button("Update") ;
 private TextField winhandle = new TextField(10) ;

  public void init() { 
    try {
      if (Class.forName("com.ms.security.PolicyEngine") != null)  // get permissions
        PolicyEngine.assertPermission(PermissionID.SYSTEM);
          doWinEnum() ;
      } 
     catch (Throwable cnfe) {  }
 
	this.setLayout(new BorderLayout()) ;
	add(ta, BorderLayout.CENTER) ;

	Panel pan = new Panel() ;
	pan.setLayout(new FlowLayout(FlowLayout.LEFT)) ;

	pan.add(new Label("Window Handle:", Label.RIGHT)) ;
	pan.add(winhandle);
	pan.add(closewindow) ;
	pan.add(new Label("     ")) ;  // spacer
	pan.add(updatewins);
	pan.add(cleartext);
	add(pan, BorderLayout.SOUTH) ;
	closewindow.addActionListener(this) ;
	closewindow.setBackground(Color.red) ;
	updatewins.addActionListener(this) ;
	updatewins.setBackground(Color.green) ;
	cleartext.addActionListener(this) ;
	cleartext.setBackground(Color.white) ;
  } 



class NewEnumProc extends com.ms.dll.Callback {           // inner class callback
    public boolean callback(int hwnd, int lparam) {
      int [] processID = new int[1] ;
      StringBuffer text = new StringBuffer(128);  //max length window title is 128 characters.
      GetWindowText(hwnd, text, text.capacity()+1);
      int threadprocessid = GetWindowThreadProcessId(hwnd, processID) ;
   
   if (text.length() != 0) {
        strb.append("hwnd: " + Integer.toHexString(hwnd) +"h    ProcID: " + processID[0] +"    Text: " + text + "\r\n" );
      } 
      return true;  // return TRUE to continue enumeration.
    }
  
 }  // end inner class





 private void doWinEnum() {
  strb = new StringBuffer(1024) ;
  NewEnumProc mycallback = new NewEnumProc();
  boolean results = false;
  results = EnumWindows(mycallback, 1) ;
  if( ! results )
    ta.setText("Problem enumerating windows") ;
   else
    ta.setText(this.strb.toString()) ;
  }


 private void closeWin32win(int winhandle) {
  SendMessage(winhandle, win.WM_SYSCOMMAND, win.SC_CLOSE, 0);
  // PostMessage(winhandle, win.WM_CLOSE, 0, 0) ;    // this also works, but SendMessage like this fails!
 }

 public void paint(Graphics g) {  // black border around applet panel
   g.setColor(Color.black) ;
   g.drawRect(0,0,this.getSize().width-1, this.getSize().height-1) ; 

  }

  public void actionPerformed(ActionEvent e) {
   if(e.getSource() == cleartext){
	winhandle.setText("") ;
	ta.setText("") ;
	}
   else
   if(e.getSource() == updatewins)
	doWinEnum();
   else
   if(e.getSource() == closewindow) {  //close the win32 window specified by textfield
	int hexhandleint = 0;
	String hexhandle = winhandle.getText().trim();
	if(hexhandle.length()==0)  //if white space only, do nothing
	 return;
	try {
	 ta.append(" Trying to close window with handle: " + hexhandle + "\n") ;
	 hexhandleint=Integer.parseInt(hexhandle, 16);
	 if(!IsWindow(hexhandleint)){
	   ta.append(" Window handle " + hexhandle + " does not exist\n") ;
	   return;
	  }
	 else     //the window exists, so close it.
	   closeWin32win(hexhandleint) ;
	   ta.append(" SendMessage(winhandle, win.WM_SYSCOMMAND, win.SC_CLOSE, 0) successful\n") ;
	}
	catch(NumberFormatException nfe) {
	 ta.append(" The window handle is NOT a hex-number\n") ;
	}
   }
  }

    /** @dll.import("USER32") */
    private static native int GetWindowText(int hwnd, StringBuffer text, int cch);

    /** @dll.import("USER32") */
    private static native int GetWindowThreadProcessId(int hwnd, int[] lpdwProcessId) ;

    /** @dll.import("USER32") */
    private static native boolean EnumWindows(NewEnumProc myproc, int param);

    /** @dll.import("USER32") */
    public static native int SendMessage (int winhandle, int message, int wparam, int lparam );

    /** @dll.import("USER32") */
    public static native boolean IsWindow (int winhandle);

}