How to find portlets added on a particular page in Liferay?

Question

How can I find which portlets are added on a particular Liferay page?

For Example:
I have three pages: Welcome, Wiki and Search.

Now all these pages have portlets added on them and some of them are instanceable portlets (like web-content display and iframe portlets).

Now I want to pass some information in the form of request parameters to the iframe-portlet on the Search page from the Welcome page.

Answer 1

I have found two ways to do this:

1. If you want to find the portlets on the same page in which your portlet is added then, you can make use of themeDisplay object available to your portlet or JSP:

   // In JSP
   List<String> portletIdList = themeDisplay.getLayoutTypePortlet().getPortletIds();
   
   // In portlet class
   ThemeDisplay themeDisplay = (ThemeDisplay) portletRequest.getAttribute(WebKeys.THEME_DISPLAY);
   List<String> portletIdList = themeDisplay.getLayoutTypePortlet().getPortletIds();
   

2. If you want to find the portlets on some different page, then you should know three things viz; friendly-url, groupId and whether this page is a public-page or private-page of the Site (or Community), so here is the code:

   // 101543 is the SiteId, if it is a public-page then "false" and "/search" is the friendlyURL
   LayoutTypePortlet layoutTypePortlet = LayoutTypePortletFactoryUtil.create(LayoutLocalServiceUtil.getFriendlyURLLayout(101543, false, "/search"));
   List<String> portletIdList = layoutTypePortlet.getPortletIds();
   

The portletIdList contains the portletIds complete with their instanceIds. So now from the list you can just filter out the iframe-portlet on the /search page by using com.liferay.portal.util.PortletKeys.IFRAME and you will get something like 48_INSTANCE_rPv9.