/**
     * <p>Return the <code>FacesContext</code> instance for the
     * current request.
     */
     public   static  FacesContext context() {
         return  (FacesContext.getCurrentInstance());
    }

/**
     * Поиск параметра в сессии
     */
     public   static  String findSessionParameter(String key){
         return  (String)context().
                getExternalContext().
                getSessionMap().
                get(key);
    }

/**
     * Кладем чего нибудь в сессию
     */
     public   static   void  setSessionParameter(String key, Object value){
        context().
                getExternalContext().
                getSessionMap().
                put(key, value);
    }
    
    /**
     * Удаление параметра из сессии.
     */
     public   static   void  removeSessionParameter(String key){
        context().
                getExternalContext().
                getSessionMap().
                remove(key);
    }

/**
     * <p>Return the <code>ShoppingCart</code> instance from the
     * user session.</p>
     */
     protected  ShoppingCart cart() {
        FacesContext context = context();
        ValueBinding vb =
                context.getApplication()
                .createValueBinding("#{cart}");
        
         return  ((ShoppingCart) vb.getValue(context));
    }

<managed-bean>
    <description>
      Create a shopping cart in session scope the first
      time it is referenced.
    </description>
    <managed-bean-name>cart</managed-bean-name>
    <managed-bean-class>cart.ShoppingCart</managed-bean-class>
    <managed-bean-scope>session</managed-bean-scope>
  </managed-bean>