How do you guys handle callbacks with Void, say you really don't want
anything returned because you are only consuming, streaming or the like?
Say you have a generified callback for extracting rows from a dataset:
public interface RowMapper[T]{
T map(Row row);
}
Implementing this for the purpose of StAX streaming rather than returning
records required one to satisfy the compiler and return something. In C# I
can just omit the return line (consistent with void semantics for classic
methods). In Java however, one has to return a derivative of Void (null):
@Override
public Void map(Row row){
staxWriter.writeStartElement(row.getString("id"));
return null;
}
That's not very nice looking at all. Cheating the type-system and
generating a Void instance through reflection is perhaps slightly cleaner
semantically, but very verbose. It's obviously related to type-erasure, but
why on earth didn't the Java compiler guys burn in a rule that would add a
"return null" if the signature is Void? Is there some idiom I am unaware of
here that would be nicer than returning null?
/Casper
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