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PODelete Entities in EventListener
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  1. PODelete Entities in EventListener
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    copied!<p>I'm working with Hibernate 4.1.1 for quite a while now. Following: I've created an EventListener which is integrated by the Integrator Interface of Hibernate. So far, this works!</p> <p>I'm trying to delete an Entity, for example an Account. An account has a one to many relation to playlists.</p> <p>What I want to achieve: Delete Playlists when Account is deleted.</p> <p>I know that I can achieve this by adding cascade behavior to my Hibernate Mappings. So far, this will work, but Hibernate isn't able to provide functionality to set a value null on cascade, so I wanted to do those steps manually:</p> <pre><code>@Override public boolean onPreDelete(final PreDeleteEvent preDeleteEvent) throws HibernateException { if (preDeleteEvent.getEntity() instanceof PresetEntry) { } else if (preDeleteEvent.getEntity() instanceof AccountEntry) { final Session session = this.sessionFactory.getCurrentSession(); if (!session.getTransaction().isActive()) { session.getTransaction().begin(); } final AccountEntry accountEntry = (AccountEntry) preDeleteEvent.getEntity(); session.createQuery("DELETE FROM PlaylistEntry WHERE ACCOUNT_ID = " + accountEntry.getIdentity()).executeUpdate(); //NON-NLS } else if (preDeleteEvent.getEntity() instanceof PlaylistEntry) { } else if (preDeleteEvent.getEntity() instanceof QueueEntry) { } return false; } </code></pre> <p>I'm running in following issues:</p> <ol> <li>A transaction is already open because the account is currently deleted</li> <li>Calling commit inside onPreDelete results in StackOverflowError (it's endlessly committing the delete playlistEntry query)</li> <li>If the query isn't commited inside the onPreDelete method the queries will be executed, however the Swing Application begins to freeze forever.</li> <li>Not removing the playlists results in foreign key no action exception</li> </ol> <p>So how can I solve that?</p>
 

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