code: public void addMBeanAttribute(String mbean, MBeanAttribute attr)
  			throws Exception {
  		MBeanHolder mbeanHolder = mbeanMap.get(mbean);
  		if (mbeanHolder == null) {
  			mbeanHolder = new MBeanHolder(this, process, mbean);
  			mbeanMap.put(mbean, mbeanHolder);
  		}
  		mbeanHolder.addAttribute(attr);
  		log.info("Added attribute " + attr + " to " + mbean);
  	}
docs: Adds an {@link info.ganglia.jmxetric.MBeanAttribute} to be sampled.
  
  @param mbean
  name of the mbean
  @param attr
  attribute to be sample
  @throws Exception