tuples and aliases

[gavinking]

A rough sketch of a possible way to deal with #888.

cc @sebersole

[sebersole]

For certain Hibernate features, it would be nice to define a proper alias across all of the TupleElement impls.

E.g. ColumnMapping currently just uses the column-name as the alias.

Consider a Hibernate feature leveraging alias with with constructor result mappings - we allow users to map these in a way such that the aliases can be used to define bean property names for use in cases where the constructed class does not have an appropriate constructor. Roughly -

class DropDownItem {
    private Integer key;
    private String text;

    // getters/setters...
}

var key = column("key", "id", Integer.class);
var text = column("text", "name", String.class);
var dto = constructor(DropDownItem.class, key, text);

Of course, this might be kind of moot depending on the decision for #887

[gavinking]

@sebersole Ok, fine, I can pull withAlias() up. Gimme 3 mins.

[gavinking]

@sebersole There, done, is that what you mean?

[gavinking]

Mmmmm @sebersole should we be targeting this one for M1?

[sebersole]

Its not critical for M1 imo.

[gavinking]

Its not critical for M1 imo.

OK then, not for M1.

[gavinking]

OK, I believe I have now cleared up the ambiguity raised in #888, along with another ambiguity in the spec with respect to what types are allowed for @ColumnResult.

I've also added support for explicit aliases in programmatic result mappings, which AFAIU we all agree is useful.

Therefore I think this one is ready to go.