0 Replies Latest reply on Mar 4, 2010 11:12 PM by Immo Benjes

    Problems with dynamic values in EL expressions

    Immo Benjes Newbie

      Hi,


      I've got a generic table where the user can select which columns are visible.
      The JSF part looks like this (as part of a table):


      <rich:columns id="#{column.id}" value="#{columns}" label="#{column.label}" var="column" index="ind" sortable="true" sortBy="#{data[column.value]}" sortOrder="#{column.sortOrder}" rendered="#{column.rendered}">
                <f:facet name="header">
                     #{column.label}
                </f:facet>
                
                <s:fragment rendered="#{column.dataType eq 'java.lang.String'}">
                            #{data[column.value]}
                       </s:fragment>
                <s:fragment rendered="#{column.dataType eq 'java.lang.Boolean'}">
                            #{data[column.value] ? 'Yes' : 'No'}
                       </s:fragment>
                <s:fragment rendered="#{column.dataType eq 'java.util.Date'}">
                            <h:outputText value="#{data[column.value]}">
                                 <s:convertDateTime pattern="#{userProfile.dateFormat}"/>
                            </h:outputText>
                       </s:fragment>
                
           </rich:columns>



      The column is a Bean which defines the column label, sorting order and which member of the actual data object (in most cases an entity) is shown in that row/column via


      #{data[column.value]}




      On the java side you would define the column with something like



      new Column(1,"Column Label","memberName");




      with memberName being the member of the entity you want to show in that column.
      So in the JSF page you would get




      #{data[memberName]}





      . That all works fine when you only want to access members in the entity. But e.g. you have a Object Company in the entity and that Company class has a member String companyName. You don't want to show Company in the data table but company.companyName


      The problem is if you specify


      new Column(1/*index*/,"Column Label","company.companyName");



      You get


      sortBy="#{data[column.value]}": Property 'company.companyName' not found on type XXX



      I've tried:



      company.companyName
      company.getCompanyName
      company[companyName]




      all with no success. It seems you can't really nest EL expressions. Do you know a way to do it?


      I then tried to write my own tag handler (see here:
      http://seamframework.org/Documentation/CreatingCustomELFunctions


      and do



      #{e:evalEl(e:concat('data.',column.value))}




      but that doesn't work either.


      Any suggestions? My last resort is to have a method
      getObj(Object data)
      on Column which uses Reflection to find the right members but there must be a better way.