Problem Context.
I came across a unique business problem and found such solution is not available on the web so writing this blog might help others.
Sling Link Rewriting based on sling: pipeline is mainly focused on how to rewrite any anchor link inside or any html element i.e. <a> <form> <img> where SAX Transformer API rewrites html data through events.
Please refer to the Adobe Wiki
http://helpx.adobe.com/cq/kb/HowToImplementACustomRewriterTransformerFactory.html
Above wiki is very helpful if rewrite need to be done for any html element where start () method needed to be implement for custom business logic.
But what about if you need to overwrite or replace value of any string in the html not in side any html tag?
public void characters(char[] ac, int i, int j) throws SAXException {}
By implementing above method of the same class that almost split html line by line and based on that it returns offset and total length of the string.
This helps content author to use String token during content authoring and would be overwritten during rendering of the page from central generic location.