title: How to call another portlet @RenderMapping method in liferay + springmvc?
body: <p>I have 2 liferay+springmvc portlet applications (2 war files). </p>
  
  <p>First portlets is Category portlet which lists all the available categories. When a category link is clicked i will display products(default page) page with list of products from the selected category in portlet-2. I am communicating the selected category via PortletSession. </p>
  
  <p>In portlet-2, user can add products to cart and navigate to cart page(which is also in portlet-2). </p>
  
  <p>Now if user clicks another category on portlet-1 then I wan to display products(default) pages. But currently what is happening is when a category link is clicked on portlet-1 then cart page is re-rendered because cart page is active now on portlet-2, which is expected.</p>
  
  <pre><code>@Controller
  @RequestMapping("VIEW")
  public class CatalogListingPortlet {
  
      @Autowired
      private CategoryRepository categoryRepository;
  
      @RenderMapping
      public String handleRenderRequest(RenderRequest request, RenderResponse response, Model model) {
          model.addAttribute("categories", categoryRepository.findAll());
          return "categories";
      }
  
      @ActionMapping(params = "action=showCategory")
      public void showCategory(ActionRequest request, ActionResponse response) {
          String categoryId = ParamUtil.get(request, "categoryId",StringPool.BLANK);
          request.setAttribute("categoryId", categoryId);
          PortletSession portletSession = request.getPortletSession();
          portletSession.setAttribute("LIFERAY_SHARED_categoryId", categoryId, PortletSession.APPLICATION_SCOPE);
      }
  }
  
  
  @Controller
  @RequestMapping("VIEW")
  public class ProductListingPortlet
  {
      @Autowired
      private CategoryRepository categoryRepository;
  
      @Autowired ProductRepository productRepository;
  
      @RenderMapping
      public String handleRenderRequest(RenderRequest request, RenderResponse response, Model model) {
          PortletSession portletSession = request.getPortletSession();
          String categoryId = (String) portletSession.getAttribute("LIFERAY_SHARED_categoryId", PortletSession.APPLICATION_SCOPE);
          Category category = categoryRepository.findOne(Long.parseLong(categoryId));
          List&lt;Product&gt; products = category.getProducts();
          portletSession.setAttribute("PRODUCTS", products);
          return "products";
      }
  
      @ActionMapping(params = "action=addProductToCart")
      public void addProductToCart(ActionRequest request, ActionResponse response) {
          //logic to add the selected product to cart       
      }
  
      @RenderMapping(params = "action=checkout")
      public String checkout(RenderRequest request, RenderResponse response, Model model) {
          return "checkout";
      }
  
  }
  </code></pre>
  
  <p>When user clicks on a category link in portlet-1 then I want to invoke @RenderMapping method in portlet-2. </p>
  
  <p>To be specific from <strong>CatalogListingPortlet.showCategory()</strong> method I need to trigger <strong>ProductListingPortlet.handleRenderRequest()</strong> method. </p>
  
  <p>How can I do it?</p>