Why is setFirstResult expecting an int instead of a long ?

stephaneeybert · **Joined:** Mon Apr 16, 2007 8:10 am **Posts:** 246

I have a pagination method to return a page:

Code:

   @SuppressWarnings("unchecked")
   public Page<T> getPage(final int pageNumber, final int pageSize, final Criteria criteria) {
      int totalSize = 0;
      if (pageSize > 0) {
         // Save the original Projection and ResultTransformer if any
         CriteriaImpl criteriaImpl = (CriteriaImpl) criteria;
         Projection originalProjection = criteriaImpl.getProjection();
         ResultTransformer originalResultTransformer = criteriaImpl.getResultTransformer();
         criteria.setProjection(Projections.rowCount());
         // TODO I don't like this intValue on a Long
         // Why is uniqueResult returning a Long and setFirstResult requiring
         // an int ?
         totalSize = ((Long) criteria.uniqueResult()).intValue();
         int startIndex = Page.getStartIndex(pageNumber, pageSize, totalSize);
         criteria.setFirstResult(startIndex);
         criteria.setMaxResults(pageSize);
         criteria.setProjection(originalProjection);
         criteria.setResultTransformer(originalResultTransformer);
      }
      List<T> list = criteria.list();
      return new Page<T>(pageNumber, pageSize, totalSize, list);
   }

As you can see in the method body, there is a:

totalSize = ((Long) criteria.uniqueResult()).intValue();

casting a long to an int.

I had to do this because uniqueResult() returns a long, indeed the size can be really long.

But the method setFirstResult expects an int.

So I had to do the casting.

Why is setFirstResult expecting an int instead of a long ?

Thanks.

Stephane

janu019 · **Joined:** Sat Nov 07, 2009 10:31 am **Posts:** 22

We need to give the index always as int.

stephaneeybert · **Joined:** Mon Apr 16, 2007 8:10 am **Posts:** 246

I understand Hibernate requires that.

But I do not understand why.

What is the rationale ?

For example in a very big table, what if the index is too large for an int ?

And why is the count being returned as a long then ?

janu019 · **Joined:** Sat Nov 07, 2009 10:31 am **Posts:** 22

Yes. I too dont understand . even JPA has the same api

query.setFirstResult(int startindex).

May be a defect in hibernate.:(

stephaneeybert · **Joined:** Mon Apr 16, 2007 8:10 am **Posts:** 246

I would think Hibernate has a good reason for that int type, but it escapes me..

nordborg · **Posted:** Thu Aug 11, 2011 5:01 am

I don't know the reason but some (long) time ago count queries used to return the result as an int. This was changed to long due to some JPA requirements (I think). You can probably find an issue in the JIRA about this. Still leaves the question why JPA has Query.setFirstResult(int) and not Query.setFirstResult(long). But I don't have an answer for that.

stephaneeybert · **Joined:** Mon Apr 16, 2007 8:10 am **Posts:** 246

Strange that such a commonly used method would not raise questions over its use of the int type. Thanks for your comment anyway.

stephaneeybert · **Joined:** Mon Apr 16, 2007 8:10 am **Posts:** 246

Any new take on this ?

stephaneeybert · **Joined:** Mon Apr 16, 2007 8:10 am **Posts:** 246

No one ?