添加新的attributeModifier时，如何删除以前的attributeModifier？

add(new AttributeModifier(\"style\", true, new Model<String>(\"background-color:#80b6ed;\")));

new Model<String>(\"background-color:#80b6ed;\")

new Model<String>() {
   @Override
   public String getObject() {
     if( columnName.equals( selectedColumn ) { //or something along these lines, to check if the current column is the selected one
        return \"background-color:#80b6ed;\";
     }
     return \"background-color:white;\";
   }
}