CODEWITHSUNDEEP
javahibernatelazy-loading
armnotstrong
armnotstrong

Reputation: 9065

How to know if the Child Entity is loaded or not in the Parent Entity in hibernate

I have a hibernate Entity with relationship mapping with fetch=FetchType.LAZY

Like:

....
private ConsumerEntity consumerEntity;

@ManyToOne(fetchType.LAZY)
@JoinColumn(name="orderId", insertable=false, updateable=false)
public ConsumerEntity getConsumerEntity(){
    return this.consumerEntity;
}
....

And I want to transfer the entity object to HashMap<String, Object>, I do that with Introspector and currently just ignore the child-entities ,only parse the non-entity member to the map:

protected Map<String, Object> transBean2Map(Object beanObj){
        Map<String, Object> map = new HashMap<String, Object>();
        try {
            BeanInfo beanInfo = Introspector.getBeanInfo(beanObj.getClass());
            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
            for (PropertyDescriptor property : propertyDescriptors) {
                String key = property.getName();

                if (!key.equals("class")
                       && !key.endsWith("Entity")) {
                    Method getter = property.getReadMethod();
                    Object value = getter.invoke(beanObj);
                    map.put(key, value);
                }
            }
        } catch (Exception e) {
            Logger.getAnonymousLogger().log(Level.SEVERE,"transBean2Map Error " + e);
        }
        return map;
    }

I want to put every child-entities in the map as a embedded map, ONLY IF they were already fetched(maybe by explicitly invoking the getter() method or accidentally loaded by other method, giving bonus information when not bothering a lot will always a good idea, right?).

And NO, I don't want to make every thing as fetchType.EAGER. Just want to detect if the child-entities are already loaded, then transfer and embedding them to the parent Map, otherwise, do nothing(won't query the db to fetch it).

Doing the embedding won't bother a lot, maybe just some recursions. So what I need is to know whether or not the child-entities are already loaded in the the parent entity, just like the consumerEntity in the example above.

Is there any way I can do that?

Upvotes: 0

Views: 522

Answers (1)

Predrag Maric
Predrag Maric

Reputation: 24433

Hibernate provides some tools for this, here is what you can try

if (HibernateProxy.class.isInstance(entity.getConsumerEntity())) {
    HibernateProxy proxy = HibernateProxy.class.cast(entity.getConsumerEntity());
    if (proxy.getHibernateLazyInitializer().isUninitialized()) {
        // getConsumerEntity() IS NOT initialized
    } else {
        // getConsumerEntity() IS initialized
    }
}

Upvotes: 3

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