@Override
 public String getSolrCoreName() {
   String coreName = solrCore.getCoreName();
   if (StringUtils.isBlank(coreName)) {
     coreName = "collection";
   }
   return coreName;
 }
 public String getSolrRequestUrl(String handler) {
   String baseUrl = GWT.getHostPageBaseURL();
   String coreName = solrCore.getCoreName();
   StringBuffer sb = new StringBuffer();
   sb.append(baseUrl).append(coreName);
   sb.append("/").append(handler);
   return sb.toString();
 }