toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse
function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString
to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
String repr = "";
repr += year?.toString().padLeft(4, '0') ?? "XXXX";
repr += "-";
repr += month?.toString().padLeft(2, '0') ?? "XX";
repr += "-";
repr += day?.toString().padLeft(2, '0') ?? "XX";
return repr;
}