<h:commandButton value="Показать" immediate="false"         actionListener="#{trafficDetailsBean.process}">
    <f:param name="period" value="custom" />
</h:commandButton>

     public   void  process(ActionEvent _event)
    {
         if  (_event !=  null )
        {
            System.out.println("_EVENT IS NOT NULL");
            UICommand command = (UICommand)_event.getComponent();
            List commandChildren = command.getChildren();
             for  (Iterator it = commandChildren.iterator(); it.hasNext(); ) 
            {
                System.out.println("->");
                UIComponent child = (UIComponent)it.next();
                 if  (child  instanceof  UIParameter) 
                {
                    System.out.println("!!parametr");
                    String parmName = (String)((UIParameter)child).getName();
                    String parmValue = (String)((UIParameter)child).getValue();
                     if  (parmName.equals("period"))
                        period = parmValue;
                }
            } 
        }
         else 
        {
            System.out.println("_EVENT IZ NULL (((((((((((((((((((((((");
        }
        
        setDates();
        test.setValue(period);
        
        System.out.println("period: " + period);
    }

<%@ include file="./right.inc.jsp" %>

...
<h:form id="rf">
    <h:outputText value="Текущий" />
    <h:commandLink value="день" immediate="false"
            actionListener="#{trafficDetailsBean.process}">
    	<f:param name="period" value="day" />
    </h:commandLink>
    <h:outputText value="/" />
    <h:commandLink value="месяц" immediate="false"
            actionListener="#{trafficDetailsBean.process}">
    	<f:param name="period" value="month" />
    </h:commandLink>
</h:form>
...