I think you need one enum per class type (I don't see how you could have one enum cover several types and keep the thing working). In that case, a common generic interface could do what you want. You can then create some sort of factory to provide the enum constants if that helps.
This compiles:
static interface ParameterType<T> {}
static enum ParameterTypeEnum implements ParameterType<String> { EMAIL; }
public static void main(String[] args) {
ParameterBuilder
.start(ParameterTypeEnum.EMAIL)
.setName("email")
.setDefaultValue("foo@bar.com")
.build();
}
public static class ParameterBuilder<T> {
private String name;
private T defaultValue;
public static <T2> ParameterBuilder<T2> start(ParameterType<T2> paramType) {
return new ParameterBuilder<T2>();
}
ParameterBuilder<T> setName(String name) {
this.name = name;
return this;
}
ParameterBuilder<T> setDefaultValue(T defaultValue) {
this.defaultValue = defaultValue;
return this;
}
void build() {}
}