[luxor-xul-develop] Possible method for extending XUL tag set in Luxor

[mhenderson <mhe...@be...>]

Hi,
    I looked over the 1.0b5 source code and tried a technique
to externalize the mapping from xul element tag (<button>, etc) to the
XULNode class.

I modified XulLoader.java:

/*
** Luxor - XML User Interface Language (XUL) Toolkit
** Copyright (c) 2001, 2002 by Gerald Bauer
**
** This program is free software.
**
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE.
**
*/

package luxor.core;

import java.lang.reflect.*;
import java.io.*;
import java.util.*;
import org.jdom.*;
import org.jdom.input.*;
import luxor.core.box.*;
import luxor.core.data.*;
import luxor.core.grid.*;
import luxor.core.input.*;
import luxor.core.menu.*;
import luxor.core.misc.*;
import luxor.core.portal.*;
import luxor.core.tab.*;
import luxor.core.table.*;
import luxor.core.toolbar.*;
import luxor.core.widget.*;
import luxor.core.xslt.*;
import houston.*;
import luxor.*;

public class XulLoader
{

	private static Properties defMap;

    static {
        try {
            defMap = new Properties();

defMap.load(XulLoader.class.getResourceAsStream("XulNodeMap.properties"));
        }
        catch (Exception ex) {

        }
    }

    private static String getDefClassNameForType(String type) {
        return (String)defMap.get(type);
    }

   static Logger T = Logger.getLogger( XulLoader.class );

   private XulManager _manager;

   public XulLoader( XulManager manager )
   {
      _manager = manager;
   }

   public void load( String name )
   {
      try
      {
         T.debug( "loading xul file " + name );
         InputStream in = _manager.getResourceAsStream( name );

         SAXBuilder builder = new SAXBuilder();
         Document doc = builder.build( in );

         Element xul = doc.getRootElement();
         createElements( null, xul );
         T.debug( "xul file " + name + " successfully loaded" );
      }
      catch( JDOMException jex )
      {
         Xul.error( "failed to load xul file '" + name + "': " +
jex.toString() );
      }
   }

   protected void createElements( XulContainer parent, Element element )
   {
       String type = element.getName();
       if( type.equals( Xul.Element.XUL ) )
       {
           parent = new XulDef( element, _manager );
       }
       else
       {
           try {
               String       defClassName = getDefClassNameForType(type);
               Class        defClass     = Class.forName(defClassName);
               Class[]      types        = new Class[] { Element.class, };
               Constructor  constructor  = defClass.getConstructor(types);
               Object[]     args         = new Object[] { element };
               XulNode      def          =
(XulNode)constructor.newInstance(args);

               parent.add(def);
               parent = (def instanceof XulContainer) ? (XulContainer)def :
null;
           }
           catch (Exception ex) {
				System.out.println("Exception: " + ex);
				ex.printStackTrace();
               Xul.syntax( "unsupported element '" + type + "'" );
           }
       }

       if (parent != null)
       {
       		// process children
      		List list = element.getChildren();
      		for( Iterator it = list.iterator(); it.hasNext();  )
      		{
         		Element child = ( Element ) it.next();
         		createElements( parent, child );
      		}
       }


   }


}

// END of source


and added a properties file:


anim=luxor.core.misc.AnimDef

box=luxor.core.box.BoxDef
button=luxor.core.input.ButtonDef
caption=luxor.core.box.CaptionDef
checkbox=luxor.core.input.CheckBoxDef

choice=luxor.core.input.ChoiceDef

col=luxor.core.widget.ColDef

colgroup=luxor.core.widget.ColGroupDef
column=luxor.core.grid.ColumnDef
columns=luxor.core.grid.ColumnsDef

command=luxor.core.misc.CommandDef
componentref=luxor.core.widget.ComponentRef

datagrid=luxor.core.widget.DataGridDef

displayurl=luxor.core.menu.DisplayUrlDef
entry=luxor.core.data.ListEntryDef
gadgetluxor.core.widget.ComponentRef

grid=luxor.core.grid.GridDef
groupbox=luxor.core.box.GroupBoxDef
hbox=luxor.core.box.HBoxDef
icon=luxor.core.misc.IconDef
iframe=luxor.core.widget.IFrameDef

image=luxor.core.widget.ImageDef
key=luxor.core.misc.KeyDef

keyset=luxor.core.misc.KeySetDef
# more fancy synomym for componentref
label=luxor.core.input.LabelDef
list=luxor.core.data.ListDef
map=luxor.core.data.MapDef

mchoice=luxor.core.input.MChoiceDef

menu=luxor.core.menu.MenuDef
menubar=luxor.core.menu.MenuBarDef
menuitem=luxor.core.menu.MenuItemDef
menupopup=luxor.core.menu.MenuPopupDef
menuref=luxor.core.menu.MenuRef
menuseparator=luxor.core.menu.MenuSeparatorDef

password=luxor.core.input.PasswordDef
popup=luxor.core.menu.PopupDef
portal=luxor.core.PortalDef
portlet=luxor.core.PortletRef
pre=luxor.core.misc.PreDef
row=luxor.core.grid.RowDef
rows=luxor.core.grid.RowsDef
separator=luxor.core.widget.SeparatorDef

spacer=luxor.core.widget.SpacerDef

stylesheet=luxor.core.xslt.StylesheetDef
tab=luxor.core.tab.TabDef

tabbox=luxor.core.tab.TabBoxDef
table=luxor.core.table.TableDef
tabpanel=luxor.core.tab.TabPanelDef
tabpanels=luxor.core.tab.TabPanelsDef
tabs=luxor.core.tab.TabsDef
td=luxor.core.table.TableDataDef
text=luxor.core.input.TextDef
textarea=luxor.core.input.TextAreaDef

toolbar=luxor.core.toolbar.ToolBarDef
toolbarbutton=luxor.core.toolbar.ToolBarButtonDef
toolbarseparator=luxor.core.toolbar.ToolBarSeparatorDef
tr=luxor.core.table.TableRowDef
tree=luxor.core.widget.TreeDef
vbox=luxor.core.box.VBoxDef


I tested this with box.jnlp in ramses and it seemd to work.

It's just a quick hack, and it might be better to use an xml file format
where the content can be extended eg:

<xul-tag name="button" node="luxor.core.input.ButtonDef" />

One benefit here is that the set of tags can be extended, especially if the
'discovery' mechanism searches for these tag mapping files on the class
path.

I would prefer to have a separate class to deal with this mapping
(XulNodeMap?) and let XulLoader deal with it via an interface. The
implementation of the interface could be decided from a config file which
would make the thing pluggable (Swing/SWT?)

What do you think?

Mike