How to load all entities in JPA given the collection of their primary keys?

Question

I'd like to write a generic method in JPA 2 that can load all entities of class T if it is given the collection of their primary keys. Here is the signature of the desired method:

public <T> List<T> getEntityList(final Class<T> entityClass, final Collection<Object> primaryKeys)

Is it possible somehow even if I don't know the entity class nor the primary key class?

Have a look here: http://stackoverflow.com/a/11349052/870122 and http://stackoverflow.com/a/9325205/870122 — perissf, Oct 18 '12 at 13:36

NimChimpsky · Answer 1 · 2012-10-18T12:32:40.043

-1

public <T> List<T> getEntityList(final Class<T> entityClass, final Collection<Object> primaryKeys)
    final Session session = sessionFactory.getCurrentSession();
    final Criteria crit = session.createCriteria(entityClass);
    crit.add(Restrictions.in("id", primaryKeys);
return crit.list();

Using a criteria query and hibernate makes it pretty simple. The JPA way is pretty similar I think.

edited Oct 18 '12 at 12:32

answered Oct 18 '12 at 12:19

NimChimpsky

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but then he asks for JPA, and you give Hibernate-specific – DataNucleus Oct 18 '12 at 12:24
@DataNucleus yeah I just noticed that – NimChimpsky Oct 18 '12 at 12:24
You cannot make sure that the primary key column is called `id` – jabal Oct 18 '12 at 12:28
yes, the main problem is that we don' t know before what is the primary key. – Andrea T Oct 18 '12 at 12:53
you could return each entity indifualyl using a plain old get(type, id) – NimChimpsky Oct 18 '12 at 13:13

How to load all entities in JPA given the collection of their primary keys?

1 Answers1