code: @Override
  	public boolean setPrevGroup(String prevGroup) {
  		if (LOGGER.isTraceEnabled()) LOGGER.trace(String.format("set previous group : %s", prevGroup));
  		this.prevGroup = prevGroup;
  		return true;
  	}
docs: /* (non-Javadoc)
  @see de.chandre.admintool.quartz.AdminToolQuartzService#setPrevGroup(java.lang.String)