criteria = createCriteria("employee");
criteria.add(Restrictions.eq("name", "John"));
criteria.addOrder(Order.asc("city"));
criteria.addOrder(Order.asc("state"));
List result = criteria.list();
This statement returns a list of Employee
objects. How can I make it return a Set
of Employee objects instead, in order to remove duplicate data?
I understand I can achieve this by creating a set out of the returned list like below, but then I would lose the sorting order of the list. And I don't want to have to write code to sort the set.
Set<Employee> empSet = new HashSet<Employee>(result);
I don't think it's possible to return a Set
using Criteria
based on the javadoc. However, if you want to remove duplicate data, why don't add a Projections.distinct(...)
to your existing Criteria
to remove the duplicates?
http://docs.jboss.org/hibernate/envers/3.6/javadocs/org/hibernate/criterion/Projections.html
UPDATE
For example, if you want to apply a SELECT DISTINCT
on the employee name (or some identifier(s)) to get a list of unique employees, you can do something like this:-
List result = session.createCriteria("employee")
.setProjection(Projections.distinct(Projections.property("name")))
.add(Restrictions.eq("name", "John"))
.addOrder(Order.asc("city"))
.addOrder(Order.asc("state"))
.list();
This way, you don't really need to worry about using Set
at all.
As the comments and javadoc suggest, you have to return a List
from Criteria . Therefore, your only option is to remove uniques after the fact. As KepaniHaole said, you should use a LinkedHashSet if you want to preserve order.
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