code: public static final void setWriter(String format, TreeWriter writer) {
  		String key = format.toLowerCase();
  		writers.put(key, writer);
  		if (JSON.equals(key)) {
  			cachedJsonWriter = writer;
  		}
  	}
docs: Binds the given TreeWriter instance to the specified data format.
  
  @param format
  name of the format (eg. "json", "xml", "csv", etc.)
  @param writer
  TreeWriter instance for generating the specified format