Null check for a value in Sightly in AEM 6.4

Hi All,

I have created a component which has a list value being returned from Java. Everytime I author the component the value obtained in the html is null. In the logs it gives a null pointer exception. The values in these fields are coming from tagging in AEM. How do I place a null check condition in the component? PFB the snippet of the code in sightly :

<div data-sly-list.collist="${column.getcolumnList}" data-sly-unwrap>

     <div class="pr-0 pl-0 outer-container ${properties.padding} ${collist.getparentClass}" style="" >

          <div class="inner-container ${collist.getchildClass} ${collist.getCorners}"  style=";border-color:${collist.getBordercolor !=null ? collist.getBordercolor : '' @ context = 'unsafe'}">

             <div data-sly-resource="${ @path=collist.getNumber, resourceType='foundation/components/parsys'}">

           </div>

      </div></div>

Note: I have to add the condition for ${collist.getparentClass} and ${collist.getchildClass}

Arun Patidar​ smacdonald2008​