code: public String setAppender(String appender) {
  		int pipe = appender.indexOf('|');
  		if(pipe>=0) {
  			String rv;
  			System.setProperty(
  				"LOG4J_FILENAME_"+(rv=appender.substring(0,pipe)),
  				root + appender.substring(pipe+1) + (printPID?('-' + pid):"") + ".log");
  			return rv;
  		} else {
  			System.setProperty(
  				"LOG4J_FILENAME_"+appender,
  				root + appender + (printPID?('-' + pid):"") + ".log");
  			return appender;
  		}
  		
  	}
docs: Accepts a String.
  If Separated by "|" then first part is the Appender name, and the second is used in the FileNaming
  (This is to allow for shortened Logger names, and more verbose file names)
  
  @param appender
  
  returns the String Appender