PageBuilder2 theme architecture - Default.jsp

IBM introduced PageBuilder2 theme in WPS 7.0, it allows user to define the theme using static html file, it seems that there are different pieces and i wanted to check how the different pieces fit together, so i started debugging theme and these are my notes

Even though the PageBuilder2 theme is changed one thing is still same which is Default.jsp file in the theme acts as entry point, it controls the overall theme. This is how the Default.jsp of PageBuilder2 theme looks like

<%@ page session="false" buffer="none" %>
<%@ page trimDirectiveWhitespaces="true" %>
<%-- Licensed Materials - Property of IBM, 5724-E76, (C) Copyright IBM Corp. 2001, 2004, 2006, 2010 - All Rights reserved. --%> 
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
<%@taglib uri="http://www.ibm.com/xmlns/prod/websphere/portal/v7.0/portal-core" prefix="portal-core" %>
<%@taglib uri="http://www.ibm.com/xmlns/prod/websphere/portal/v7.0/portal-logic" prefix="portal-logic" %>
<%@taglib uri="http://www.ibm.com/xmlns/prod/websphere/portal/v7.0/portal-fmt" prefix="portal-fmt" %>
<%@taglib uri="/WEB-INF/tld/portal-internal.tld" prefix="portal-internal" %>
<%@taglib uri="/WEB-INF/tld/resolver-v7.tld" prefix="r" %>
<portal-core:constants/>
<portal-core:defineObjects/>
<portal-internal:adminNavHelper/>
<%@ include file="./bootstrap.jspf" %>
<%@ include file="./bootstrapPortal.jspf" %>
<%-- The theme template is determined by whether there is a value set in page meta data, 
if no value is set in the meta data, then it defaults to the template stored in webdav --%>
<c:choose>
 <c:when test="${empty themeWebDAVBaseURI}">
   <c:set var="themeTemplateURI" value="" />
 </c:when>
 <c:when test="${empty dirMD['com.ibm.portal.theme.template.file.name.html']}">
   <c:set var="themeTemplateURI" value="${themeWebDAVBaseURI}theme.html" />
 </c:when>
 <c:otherwise>
   <c:set var="themeTemplateURI" value="${themeWebDAVBaseURI}${dirMD['com.ibm.portal.theme.template.file.name.html']}" />
  </c:otherwise>
</c:choose>
<c:choose>
  <c:when test="${!empty themeTemplateURI}">
    <r:dataSource uri="spa:${wp.identification[wp.selectionModel.selected]}" escape="none">
   <r:param name="themeURI" value="${themeTemplateURI}"/>
   <r:param name="mime-type" value="text/html"/>
    </r:dataSource>
  </c:when><%-- If no theme template is found, the fallback.jsp is rendered--%>
  <c:otherwise>
 <%@ include file="./fallback.jsp" %>
  </c:otherwise>
</c:choose>

The Default.jsp is very simple and it does not have any HTML markup generation code at all. The functionality of Default.jsp can be broken into 3 parts

• Initializing variables required for the theme: At the start of the Default.jsp it is forwarding control to bootstrap.jspf and bootstrapPortal.jspf, It looks like these two files are used for initializing all the variables that are required for theme. Things like if user is logged in, if yes what is userId, available locale, paths to contenthandler and also some variables that are required for calculating themeTemplateURI


• Cacluate value of themeTemplateURI Next it tries to calculate value of themeTemplateURI. In the default implementation it will always be dav:fs-type1/themes/PageBuilder2/theme.html but your allowed to override this value at page level as well as at theme level


• Forwarding control to r:dataSource for generating markup Once the value of themeTemplateURI is calculated control will fowarded to r:dataSource jsp tag, and this tag will be responsible for parsing theme.html, evaluating dynamic content spot, and generating final html markup