I'm not committed to any particular GUI tookit or anything - just needs to be Java based. I want to do simple syntax highlighting ( XML and XQuery ) inside editable text areas.
My only candidate so far is Swing's JTextPane, as it supports seems to support the styling of text, but I have no idea how to implement it in this context.
If a particular toolkit has something like this out of the box, that would be awesome, but I'm open to doing this by hand if need be.
JSyntaxPane handles XML and can be extended
http://code.google.com/p/jsyntaxpane/wiki/Using
Or, it should be possible to extract the NetBeans editor, but that would probably be more work...
[edit] btw, I got the XML info from here... it doesn't seem to mention it on the google code pages...
Jide software has a Syntax Highligher component. It is still in beta, but I think it supposed XML. I haven't used it myself, so I don't know how well it will do what you want.
Why not check out Ostermiller's Syntax Highlighter.
Here's a simple code editor demo
It still uses JTextPane though.