void addValue(Class<?> componentType,Object value){
  Preconditions.checkArgument(componentType == this.componentType);
  values.add(value);
}

void addValue ( Class < ? > componentType , Object value ) { Preconditions . checkArgument ( componentType == this . componentType ) ; values . add ( value ) ; }
adds a given value to the array , checking the given component type matches the previously stored component type .
