WIN 32 API calls from Java

Well I decided to go try xFunction. Seems to work pretty well. Here is a sample program that calls Beep :-) and the SystemParametersInfo function to find out the size of the desktop work area -- the part that isn't covered by the task bar.

---------- WinRect.java ----------
import com.excelsior.xFunction.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class WinRect extends Structure {
    int left;
    int top;
    int right;
    int bottom;

    public String defineLayout() {
        return "int left, int top, int right, int bottom";
    }
    public String toString() {
        return "WinRect["+left+","+top+","+right+","+bottom+"]";
    }

    public static void main(String[] args) {
     try {
            xFunction f = new xFunction("kernel32", "int Beep(int,int)");
            f.invoke(new Argument(1770), new Argument(100));
        } catch (Exception e) {
            e.printStackTrace();
        }

        WinRect rect = new WinRect();
        System.out.println("Before call: " + rect);
        try {
            /* The following is equivalent to the JNI:
                 RECT workArea;
                 SystemParametersInfo(SPI_WORKAREA, 0, &workArea, 0);
                 jint width = workArea.right - workArea.left;
                 jint height = workArea.bottom - workArea.top;
            */
            String sig = "int SystemParametersInfoA(int,int,WinRect*,int)";
            xFunction f = new xFunction("user32", sig);
            Argument arg1 = new Argument(48);
            Argument arg2 = new Argument(0);
            Pointer arg3 = Pointer.createPointerTo(rect);
            Argument arg4 = new Argument(0);
            Integer val = (Integer)f.invoke(arg1, arg2, arg3, arg4);
            rect = (WinRect)arg3.deref();
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
        System.out.println("After call: " + rect);

     int width = rect.right - rect.left;
     int height = rect.bottom - rect.top;
     System.out.println("Work area = " + width + "x" + height);

     JFrame frame = new JFrame("Maximum Work Area");
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        frame.setSize(new Dimension(width, height));
        frame.show();
    }
}
---------- end ----------

Jim