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POGrails. Hibernate lazy loading multiple objects
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  1. POGrails. Hibernate lazy loading multiple objects
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    copied!<p>I'm having difficulties with proxied objects in Grails. Assuming I've got the following</p> <pre><code>class Order { @ManyToMany(fetch = FetchType.EAGER) @JoinTable(name="xxx", joinColumns = {@JoinColumn(name = "xxx")}, inverseJoinColumns = {@JoinColumn(name = "yyy")}) @OrderBy("id") @Fetch(FetchMode.SUBSELECT) private List&lt;OrderItem&gt; items; } class Customer { @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = true) @JoinColumn(name = "xxx",insertable = false, nullable = false) private OrderItem lastItem; private Long lastOrderId; } </code></pre> <p>And inside some controller class</p> <pre><code>//this all happens during one hibernate session. def currentCustomer = Customer.findById(id) //at this point currentCustomer.lastItem is a javassist proxy def lastOrder = Order.findById(current.lastOrderId) //lastOrder.items is a proxy //Some sample actions to initialise collections lastOrder.items.each { println "${it.id}"} </code></pre> <p>After the iteration <code>lastOrder.items</code> still contains a proxy of <code>currentCustomer.lastItem</code>. For example if there are 4 items in the lastOrder.items collection, it looks like this:</p> <ul> <li>object</li> <li>object</li> <li>javassist proxy (all fields are null including id field). This is the same object as in currentCustomer.lastItem.</li> <li>object</li> </ul> <p>Furthermore, this proxy object has all properties set to null and it's not initialized when getters are invoked. I have to manually call <code>GrailsHibernateUtils.unwrapIdProxy()</code> on every single element inside <code>lastOrder.items</code> to ensure that there are no proxies inside (which basically leads to EAGER fetching).</p> <p>This one proxy object leads to some really weird Exceptions, which are difficult to track on testing phase.</p> <p>Interesting fact: if I change the ordering of the operations (load the order first and the customer second) every element inside <code>lastOrder.items</code> is initialized.</p> <p>The question is: Is there a way to tell Hibernate that it should initialize the collections when they are touched, no matter if any elements from the collection is already proxied in the session?</p>
 

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