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copied!<p>This should (?) work:</p> <pre><code>abstract class DAO[T, K <: Serializable](implicit m: Manifest[T]) { ... def findByAttributes[T](attributes:AttributeValuePair[_]*):ArrayList[T] = { val cq = cb.createQuery(m.erasure) val queryRoot = cq.from(m.erasure) var criteria = cb.conjunction for (pair <- attributes) criteria = cb.and(cb.equal(queryRoot.get(pair._1), pair._2 )) cq.where(Seq(criteria):_*) val results = em.createQuery(cq).getResultList results.asInstanceOf[ArrayList[T]] } } </code></pre> <p>[Edit]</p> <p>Aaargh!1!11!!!!</p> <p>I think you need to write <code>findByAttributes(...)</code>, not <code>findByAttributes[T](...)</code>, else that T shadows the T of the DAO class (which is the "right one"). I'm not sure that this solves your problem, but as it is, it is wrong.</p> <p>[Edit1]</p> <p>I didn't read the API careful enough. I think you want to use <a href="http://download.oracle.com/docs/cd/E17410_01/javaee/6/api/javax/persistence/criteria/Path.html#get%28javax.persistence.metamodel.SingularAttribute%29" rel="nofollow noreferrer">this Version of get</a>. </p> <p>So we would have to provide only the second type parameter of the SingularAttribute. The problem is that this would be the same as the one in AttributeValuePair[_]. I honestly don't know how to preceed here. You could try</p> <pre><code>def findByAttributes[A](attributes:AttributeValuePair[A]*):ArrayList[T] = {... </code></pre> <p>or</p> <pre><code>queryRoot.get[A](pair._1.asInstanceOf[SingularAttribute[T,A]]) </code></pre> <p>If this doesn't work, we get at least some interesting error messages, which may give us a hint :-)</p>

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