Implementing a Guestbook Asset Renderer

Implementing Asset Renderers
Step 1 of 2

Liferay DXP’s asset renderers follow the factory pattern, so you must create a GuestbookAssetRendererFactory that instantiates the GuestbookAssetRenderer’s private guestbook object. Here, you’ll create both classes.

Get started by creating the Asset Renderer class first.

Creating the AssetRenderer Class

Follow these steps to create the GuestbookAssetRenderer class:

1. Create a new package called com.liferay.docs.guestbook.asset in the guestbook-service module’s src/main/java folder. In this package, create a GuestbookAssetRenderer class that extends Liferay DXP’s BaseJSPAssetRenderer class. Extending this class gives you a head-start on implementing the AssetRenderer interface. Start with this code:

   package com.liferay.docs.guestbook.asset;
   
   import com.liferay.asset.kernel.model.BaseJSPAssetRenderer;
   import com.liferay.portal.kernel.exception.PortalException;
   import com.liferay.portal.kernel.exception.SystemException;
   import com.liferay.portal.kernel.model.LayoutConstants;
   import com.liferay.portal.kernel.portlet.LiferayPortletRequest;
   import com.liferay.portal.kernel.portlet.LiferayPortletResponse;
   import com.liferay.portal.kernel.portlet.PortletURLFactoryUtil;
   import com.liferay.portal.kernel.security.permission.ActionKeys;
   import com.liferay.portal.kernel.security.permission.PermissionChecker;
   import com.liferay.portal.kernel.util.HtmlUtil;
   import com.liferay.portal.kernel.util.PortalUtil;
   import com.liferay.portal.kernel.util.StringUtil;
   import com.liferay.docs.guestbook.portlet.constants.GuestbookPortletKeys;
   import com.liferay.docs.guestbook.model.Guestbook;
   import com.liferay.docs.guestbook.service.permission.GuestbookPermission;
   import java.util.Locale;
   import javax.portlet.PortletRequest;
   import javax.portlet.PortletResponse;
   import javax.portlet.PortletURL;
   import javax.portlet.WindowState;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;
   
   public class GuestbookAssetRenderer extends BaseJSPAssetRenderer<Guestbook> {
   
   }
   

2. Add the constructor and the guestbook class variable next. Most of the methods in this class are simply getters that return fields from this private guestbook object:

   public GuestbookAssetRenderer(Guestbook guestbook) {
   
               _guestbook = guestbook;
   }
   
   private Guestbook _guestbook;
   

3. The BaseJSPAssetRenderer abstract class that you’re extending contains dummy implementations of the hasEditPermission and hasViewPermission methods that you must override. Override these dummy implementations with actual permission checks using the GuestbookPermission class that you created earlier:

   @Override
   public boolean hasEditPermission(PermissionChecker permissionChecker) 
   throws PortalException {
   
     long guestbookId = _guestbook.getGuestbookId();
     return GuestbookPermission.contains(permissionChecker, guestbookId, 
     ActionKeys.UPDATE);
   }
   
   @Override
   public boolean hasViewPermission(PermissionChecker permissionChecker) 
   throws PortalException {
   
     long guestbookId = _guestbook.getGuestbookId();
     return GuestbookPermission.contains(permissionChecker, guestbookId, 
     ActionKeys.VIEW);
   }
   

4. Add the following getter methods to retrieve information about the guestbook asset:

   @Override
   public Guestbook getAssetObject() {
     return _guestbook;
   }
   
   @Override
   public long getGroupId() {
     return _guestbook.getGroupId();
   }
   
   @Override
   public long getUserId() {
   
     return _guestbook.getUserId();
   }
   
   @Override
   public String getUserName() {
     return _guestbook.getUserName();
   }
   
   @Override
   public String getUuid() {
     return _guestbook.getUuid();
   }
   
   @Override
   public String getClassName() {
     return Guestbook.class.getName();
   }
   
   @Override
   public long getClassPK() {
     return _guestbook.getGuestbookId();
   }
   
   @Override
   public String getSummary(PortletRequest portletRequest, PortletResponse 
     portletResponse) {
       return "Name: " + _guestbook.getName();
   }
   
   @Override
   public String getTitle(Locale locale) {
     return _guestbook.getName();
   }
   
   @Override
   public boolean include(HttpServletRequest request, HttpServletResponse 
     response, String template) throws Exception {
       request.setAttribute("GUESTBOOK", _guestbook);
       request.setAttribute("HtmlUtil", HtmlUtil.getHtml());
       request.setAttribute("StringUtil", new StringUtil());
       return super.include(request, response, template);
   }
   

   The final method makes several utilities, as well as the Guestbook entity, available to Liferay DXP in the HttpServletRequest object.

5. Override the getJspPath method. This method returns a string that represents the path to the JSP that renders the guestbook asset. When the Asset Publisher displays an asset’s full content, it invokes the asset renderer class’s getJspPath method and passes a template string parameter that equals "full_content". This returns /asset/guestbook/full_content.jsp when the full_content template string is passed as a parameter. You’ll create this JSP later when updating your application’s user interface:

     @Override
     public String getJspPath(HttpServletRequest request, String template) {
   
       if (template.equals(TEMPLATE_FULL_CONTENT)) {
         request.setAttribute("gb_guestbook", _guestbook);
   
         return "/asset/guestbook/" + template + ".jsp";
       } else {
         return null;
       }
     }
   

6. Override the getURLEdit method. This method returns a URL for editing the asset:

     @Override
     public PortletURL getURLEdit(LiferayPortletRequest liferayPortletRequest,
         LiferayPortletResponse liferayPortletResponse) throws Exception {
       PortletURL portletURL = liferayPortletResponse.createLiferayPortletURL(
           getControlPanelPlid(liferayPortletRequest), GuestbookPortletKeys.GUESTBOOK,
           PortletRequest.RENDER_PHASE);
       portletURL.setParameter("mvcRenderCommandName", "/guestbookwebportlet/edit_guestbook");
       portletURL.setParameter("guestbookId", String.valueOf(_guestbook.getGuestbookId()));
       portletURL.setParameter("showback", Boolean.FALSE.toString());
   
       return portletURL;
     }
   

7. Override the getURLViewInContext method. This method returns a URL to view the asset in its native application:

     @Override
     public String getURLViewInContext(LiferayPortletRequest liferayPortletRequest,
         LiferayPortletResponse liferayPortletResponse, String noSuchEntryRedirect) throws Exception {
       try {
         long plid = PortalUtil.getPlidFromPortletId(_guestbook.getGroupId(),
             GuestbookPortletKeys.GUESTBOOK);
   
         PortletURL portletURL;
         if (plid == LayoutConstants.DEFAULT_PLID) {
           portletURL = liferayPortletResponse.createLiferayPortletURL(getControlPanelPlid(liferayPortletRequest),
               GuestbookPortletKeys.GUESTBOOK, PortletRequest.RENDER_PHASE);
         } else {
           portletURL = PortletURLFactoryUtil.create(liferayPortletRequest,
               GuestbookPortletKeys.GUESTBOOK, plid, PortletRequest.RENDER_PHASE);
         }
   
         portletURL.setParameter("mvcRenderCommandName", "/guestbookwebportlet/view");
         portletURL.setParameter("guestbookId", String.valueOf(_guestbook.getGuestbookId()));
   
         String currentUrl = PortalUtil.getCurrentURL(liferayPortletRequest);
   
         portletURL.setParameter("redirect", currentUrl);
   
         return portletURL.toString();
   
       } catch (PortalException e) {
   
       } catch (SystemException e) {
       }
   
       return noSuchEntryRedirect;
     }
   

8. Override the getURLView method. This method returns a URL to view the asset from within the Asset Publisher:

     @Override
     public String getURLView(LiferayPortletResponse liferayPortletResponse, 
     WindowState windowState) throws Exception {
   
       return super.getURLView(liferayPortletResponse, windowState);
     }
   

9. Save the class.

10. You have an error in your class, because the guestbook-service project doesn’t have access to the GuestbookPortletKeys object that’s in the guestbook-web project.

    It is logical to think this could be corrected by including the project as a dependency in guestbook-service’s build.gradle file, but that creates a circular dependency. guestbook-web already depends on guestbook-service, so you can’t make guestbook-service depend circularly on guestbook-web.

    So now what do you do?

    Make sure you’ve opened both guestbook-api and guestbook-web projects. Drag the com.liferay.docs.guestbook.portlet.constants package from the guestbook-web project and drop it on the guestbook-api project’s src/main/java folder. Blamo! You fixed the problem. guestbook-service depends on guestbook-api and implements its interfaces. guestbook-web depends on both. Now you have only linear dependencies.

Next you can create the AssetRendererFactory class.

Creating the GuestbookAssetRendererFactory Class

Follow these steps to create the GuestbookAssetRendererFactory:

1. In the com.liferay.docs.guestbook.asset package, create a class called GuestbookAssetRendererFactory that extends Liferay DXP’s BaseAssetRendererFactory class. Replace its code with this starter code:

   package com.liferay.docs.guestbook.asset;
   
   import com.liferay.asset.kernel.model.AssetRenderer;
   import com.liferay.asset.kernel.model.AssetRendererFactory;
   import com.liferay.asset.kernel.model.BaseAssetRendererFactory;
   import com.liferay.docs.guestbook.model.Guestbook;
   import com.liferay.docs.guestbook.service.EntryLocalService;
   import com.liferay.docs.guestbook.service.GuestbookLocalService;
   import com.liferay.docs.guestbook.service.permission.GuestbookPermission;
   import com.liferay.docs.guestbook.constants.GuestbookPortletKeys;
   import com.liferay.portal.kernel.util.WebKeys;
   import com.liferay.portal.kernel.exception.PortalException;
   import com.liferay.portal.kernel.portlet.LiferayPortletRequest;
   import com.liferay.portal.kernel.portlet.LiferayPortletResponse;
   import com.liferay.portal.kernel.security.permission.PermissionChecker;
   import com.liferay.portal.kernel.theme.ThemeDisplay;
   
   import javax.portlet.PortletRequest;
   import javax.portlet.PortletURL;
   import javax.servlet.ServletContext;
   
   import org.osgi.service.component.annotations.Component;
   import org.osgi.service.component.annotations.Reference;
   
   
   @Component(immediate = true, 
     property = {"javax.portlet.name=" + GuestbookPortletKeys.GUESTBOOK}, 
     service = AssetRendererFactory.class
     )
   public class GuestbookAssetRendererFactory extends 
     BaseAssetRendererFactory<Guestbook> {
   
     public GuestbookAssetRendererFactory() {
       setClassName(CLASS_NAME);
       setLinkable(_LINKABLE);
       setPortletId(GuestbookPortletKeys.GUESTBOOK);
       setSearchable(true);
       setSelectable(true);
     }
   

   This code contains the class declaration and the constructor. It sets the class name it creates an AssetRenderer for, a portlet ID, and a boolean (_LINKABLE) set to true. The boolean denotes the methods that provide URLs in the generated AssetRenderer are implemented.

2. Implement the getAssetRenderer method, which constructs new GuestbookAssetRenderer instances for specific guestbooks. It uses the classPK (primary key) parameter to retrieve the guestbook from the database. It then calls the GuestbookAssetRenderer’s constructor, passing the retrieved guestbook as an argument:

   @Override
   public AssetRenderer<Guestbook> getAssetRenderer(long classPK, int type) 
   throws PortalException {
   
     Guestbook guestbook = _guestbookLocalService.getGuestbook(classPK);
   
     GuestbookAssetRenderer guestbookAssetRenderer = 
     new GuestbookAssetRenderer(guestbook);
   
     guestbookAssetRenderer.setAssetRendererType(type);
     guestbookAssetRenderer.setServletContext(_servletContext);
   
     return guestbookAssetRenderer;
   }
   

3. You’re extending BaseAssetRendererFactory, an abstract class that implements the AssetRendererFactory interface. To ensure that your custom asset is associated with the correct entity, each asset renderer factory must implement the getClassName and getType methods (among others):

     @Override
     public String getClassName() {
       return CLASS_NAME;
     }
   
     @Override
     public String getType() {
       return TYPE;
     }
   

4. Implement the hasPermission method via the GuestbookPermission class:

   @Override
   public boolean hasPermission(PermissionChecker permissionChecker, 
   long classPK, String actionId) throws Exception {
   
     Guestbook guestbook = _guestbookLocalService.getGuestbook(classPK);
     return GuestbookPermission.contains(permissionChecker, guestbook, 
     actionId);
   }
   

5. Add the remaining code to create the portlet URL for the asset and specify whether it’s linkable:

         @Override
         public PortletURL getURLAdd(LiferayPortletRequest liferayPortletRequest,
             LiferayPortletResponse liferayPortletResponse, long classTypeId) {
           PortletURL portletURL = null;
   
           try {
             ThemeDisplay themeDisplay = (ThemeDisplay) 
             liferayPortletRequest.getAttribute(WebKeys.THEME_DISPLAY);
   
             portletURL = liferayPortletResponse.createLiferayPortletURL(getControlPanelPlid(themeDisplay),
                 GuestbookPortletKeys.GUESTBOOK, PortletRequest.RENDER_PHASE);
             portletURL.setParameter("mvcRenderCommandName", "/guestbookwebportlet/edit_guestbook");
             portletURL.setParameter("showback", Boolean.FALSE.toString());
           } catch (PortalException e) {
           }
   
           return portletURL;
         }
   
         @Override
         public boolean isLinkable() {
           return _LINKABLE;
         }
   
         @Override
         public String getIconCssClass() {
             return "bookmarks";
         }
   
       @Reference(target = "(osgi.web.symbolicname=com.liferay.docs.guestbook.portlet)",
               unbind = "-")
       public void setServletContext(ServletContext servletContext) {
               _servletContext = servletContext;
           }
           private ServletContext _servletContext;
   
       @Reference(unbind = "-")
           protected void setGuestbookLocalService(GuestbookLocalService guestbookLocalService) {
               _guestbookLocalService = guestbookLocalService; 
       }
   
       private GuestbookLocalService _guestbookLocalService;
       private static final boolean _LINKABLE = true;
       public static final String CLASS_NAME = Guestbook.class.getName();
       public static final String TYPE = "guestbook";
   }
   

6. Organize imports (Ctrl-Shift-O) and save the file.

Great! The guestbook asset renderer is complete. Next, you’ll create the entry asset renderer.

« Implementing Asset RenderersImplementing an Entry Asset Renderer »