import ij.IJ;
import ij.gui.GenericDialog;
import ij.plugin.PlugIn;

/** This plugin demonstrates how to display a dialog at a specified
     location on the screen. It required ImageJ 1.42h or later. */
public class Place_Dialog implements PlugIn {

  public void run(String arg) {
    // construct generic dialog
    GenericDialog gd = new GenericDialog("Who Are You?");
    gd.addStringField("Name: ", "", 30);
    if (IJ.getVersion().compareTo("1.42h")>=0)
        gd.centerDialog(false);
    gd.setLocation(100, 100);
    gd.showDialog();
    if (gd.wasCanceled()) return;

    // do something trivial with the input
    String name = gd.getNextString();
    if (name == null) name = "";
    name = name.trim();
    if (name.equals("")) IJ.showMessage("Hello!");
    else IJ.showMessage("Hello, " + name + "!");
  }

}