package ie.dcu.segment.options;

/**
 * The result of an attempted conversion.
 * 
 * @author Kevin McGuinness
 */
public class Conversion<T> {
	private final String message;
	private final T result;

	/**
	 * Create a conversion object with the given message and result. The message
	 * should be null if the conversion was valid.
	 * 
	 * @param result
	 *        The result, or <code>null</code>.
	 * @param message
	 *        A message, or <code>null</code>.
	 */
	public Conversion(T result, String message) {
		this.message = message;
		this.result = result;
	}

	/**
	 * Returns <code>true</code> of the conversion went OK.
	 */
	public boolean isOk() {
		return message == null;
	}

	/**
	 * Returns an error message if the conversion failed.
	 */
	public String getMessage() {
		return message;
	}

	/**
	 * Returns the result of the conversion if it succeeded.
	 */
	public T getResult() {
		return result;
	}

	public String toString() {
		if (isOk()) {
			return String.format("Conversion [ value = %s ]", result);
		} else {
			return String.format("Conversion [ error = %s ]", message);
		}
	}
}