code: int getIndexOf(final V value) {
  		Validate.notNull(value, "Value required");
  		Validate.validState(getSize() > 0, "No data");
  
  		return getData().indexOf(value);
  	}
docs: Returns the index of the first occurrence of the specified value in this
  controller, or -1 if this controller does not contain the value.
  
  @param value
  @return found index, or -1 if value was not found
  @throws NullPointerException
  if parameter value is null
  @throws IllegalStateException
  if there is no data available