code: private void setAttribute(String key, String value, boolean allowEmptyValue) {
  
          if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(value) || (allowEmptyValue && (value != null))) {
              if (m_attributes == null) {
                  m_attributes = new HashMap<String, String>();
              }
              m_attributes.put(key, value);
          }
      }
docs: Sets the given key with the given value in the attribute map.<p>
  
  @param key the key to set
  @param value the value to set
  @param allowEmptyValue flag to determine if an empty value (not <code>null</code>!) should be set