code: public void addIconRule(String extension, String icon, String bigIcon, String smallIconStyle, String bigIconStyle) {
  
          CmsIconRule rule = new CmsIconRule(extension, icon, bigIcon, smallIconStyle, bigIconStyle);
          m_iconRules.put(extension, rule);
      }
docs: Adds a new icon rule to this explorer type.<p>
  
  @param extension the extension for the icon rule
  @param icon the small icon
  @param bigIcon the big icon
  @param smallIconStyle the small icon CSS style class
  @param bigIconStyle the big icon CSS style class