By using a constructor in the SELECT clause we can instantiate a Java object with the results of our query. This Java object does not need to be an entity or be mapped onto a database. The class name corresponding to this object must be fully qualified. For example, the query
SELECT NEW ejb30.entity.CustomerRef( c.firstName, c.lastName, c.referee.name) FROM Customer c
creates a CustomerRef object which contains a customer's first and last name together with the associated referee name. The following is a partial listing for the CustomerRef class:
package ejb30.entity;
import java.io.Serializable;
public class CustomerRef implements Serializable {
private String firstName;
private String lastName;
private String refereeName;
public CustomerRef() {}
public CustomerRef(String firstName, String lastName,
String refereeName) {
this.firstName = firstName;
this.lastName = lastName;
this.refereeName = refereeName;
}
// getter and setter methods
}
Note the presence of a...