new file mode 100644
--- /dev/null
+++ b/scripts/ui/private/message_dialog.m
@@ -0,0 +1,68 @@
+## Copyright (C) 2010 Martin Hepperle
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{h} =} message_dialog (@var{caller}, @var{msg}, @var{title}, @var{icon})
+## Undocumented internal function.
+## @end deftypefn
+
+function retval = message_dialog (caller, msg, title = "", icon)
+
+  if (! ischar (msg))
+    if (iscell (msg))
+      msg = sprintf ("%s\n", msg{:});
+      msg(end) = "";
+    else
+      error ("%s: MSG must be a character string or cellstr array", caller);
+    endif
+  endif
+
+  if (! ischar (title))
+    error ("%s: TITLE must be a character string", caller);
+  endif
+  
+  dlg = "emptydlg";
+  if (nargin == 4)
+    switch (icon)
+      case "error"
+        dlg = "errordlg";
+      case "help"
+        dlg = "helpdlg";
+      case "warn"
+        dlg = "warndlg";
+      case "none"
+        dlg = "emptydlg";
+      otherwise
+        error ("%s: ICON is not a valid type", caller);
+    endswitch
+  endif
+
+  if (__have_feature__ ("JAVA"))
+    retval = javaMethod (dlg, "org.octave.JDialogBox", msg, title);
+    if (retval)
+      return;
+    endif
+  endif
+
+  ## FIXME -- provide terminal-based implementation here?
+
+  if (! retval)
+    error ("%s is not available in this version of Octave", dlg);
+  endif
+
+endfunction