As was said, a Tuple is an ordered list of things. It helps to understand why you would use such a thing. Consider that you have a table in the database and for whatever reason you only want to select some of the columns from that table. From such a query you can get Objects and Tuples. Example, consider an Entity that has two fields, latitude and longitude:
@Entity
public class User {
@Id @GeneratedValue private Long id;
private BigDecimal latitude;
private BigDecimal longitude;
When you want to query only the latitude and longitude columns, where do you put the results? One of the ways to do it is to use Tuples:
// With objects, the alias information is lost.
List<Object[]> s = em.createQuery("select u.lattitude as lattitude, u.longitude as longitude from User u", Object[].class).getResultList();
s.stream().forEach((record) -> {
System.out.println(record[0]+","+record[1]);
});
// With Tuples, the alias information is retained.
List<Tuple> t = em.createQuery("select u.lattitude as lattitude, u.longitude as longitude from User u", Tuple.class).getResultList();
t.stream().forEach((record) -> {
System.out.println( record.get("lattitude") +","+record.get("longitude"));
});
As you can see, Tuples have an alias property that gets filled out by the query, which you can then use later. This is more convenient than an Object. Also, TupleElement supports Java Generics, so you can also have more type safety than you can have with Objects.
