How to know if an EclipseLink entity is detached?

Question

Do you know any method to know the state of a JPA entity?. I'm facing some bugs and I need to know if an entity is detached or managed.

I'm using EclipseLink 2.1.2

score 7 · Accepted Answer · answered Jan 05 '11 at 15:04

7

EntityManager.contains()

Check if the instance is a managed entity instance belonging to the current persistence context.

answered Jan 05 '11 at 15:04

axtavt

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8

And if the object is managed by a different EntityManager ? it returns false ... which doesn't mean it is detached. – DataNucleus Jan 05 '11 at 17:43
[This SO post](https://stackoverflow.com/questions/13135309/how-to-find-out-whether-an-entity-is-detached-in-jpa-hibernate) discusses why @DataNucleus is correct. – Mohamed El-Beltagy Jan 07 '19 at 11:35

score 0 · Answer 2 · answered May 01 '22 at 15:25

The previous answer is partially correct.

You must check other states to have a higher degree of confidence.

I use the following code, where I have my own managed EntityManager / EntityManagerFactory.

/**
 * Check if an entity is detached or not
 * @param entity
 * @return true, if the entity is managed
 */
 public boolean isDetached(AbstractEntity entity) {
        // pick the correct EntityManager, somehow
        EntityManager em = getMyEntityManager(entity);
        try {
            if (em == null)
                return false;

            return entity.getID() != null // must not be transient
                    && !em.contains(entity) // must not be managed now
                    && em.find(Entity.class, entity.getID()) != null; // must not have been removed
        } finally {
            if (em != null)
                em.close();
        }
    }

How to know if an EclipseLink entity is detached?

2 Answers2