transform method
Implementation
String transform(String text) {
if (this == TextTransform.upperCase) {
return text.toUpperCase();
} else if (this == TextTransform.lowerCase) {
return text.toLowerCase();
} else if (this == TextTransform.capitalCase) {
return text[0].toUpperCase() + text.substring(1).toLowerCase();
} else {
return text;
}
}