I want to allow the transformer to set a param in my stylesheet to specify how many spaces of indentation are desired. I have tried all of the suggestions by @Dimitre Novatchev
As @Mads Hansen already said it does not appear that Xalan supports attribute value templates for the value of the xalan:indent-amount
attribute.
I found that setting the property on the transformer itself does work though. The nice thing about this is that I don't have to create/modify any files.
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
Credit goes to @Flynn1179