Dynamic association fetching...

hejain · **Posted:** Sun Dec 26, 2004 2:49 pm

Hello Everyone..
I have a requirement where i want to make use of hibernate lazy loading feature for associations i have as well as want to dynamically override the same to load all the associations based on a parameter to the method which fetches the data. I tried using setFetchMode(association, FetchMode.EAGER) but here there is a restriction that i can load only one one-to-one and only one one-to-many association. But my objects have more than one associations of a single type. Any clues on how can i achieve the same. Is there are possibility to override at run time hibernates lazy loading feature and make it to load all the association. Any help in this regards would be appreciated.

Thanks..
hejain
Hibernate version:
2.x

Mapping documents:

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:

Name and version of the database you are using:
MySQL
The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

clajoie · **Posted:** Sun Dec 26, 2004 6:30 pm

I've had this need before as well. I wrote a very simple util class to take care of this. The class has a set of static integers (powers of 2) that represent all the possible associations on a particular POJO. Then I have a method that takes the POJO whose associations are to be intialized and an integer which represents all the association that need to be initialized. Here's an example:

Code:

public class ModelPrepUtil {

    /**
     * Represents the violation types component of an enforcement.
     */
    public final static int VIOLATIONS_TYPES = 1;
    
    /**
     * Represents the relief component of an enforcement.
     */
    public final static int RELIEFS = 2;
    
    /**
     * Represents the defendants/respondants types component of an enforcement.
     */
    public final static int DEFENDANTS_RESPONDANTS = 4;
    
    /**
     * Represents the environmental justices component of an enforcement.
     */
    public final static int ENVIRONMENTAL_JUSTICES = 8;

    public final static void initalizeSelectedComponents(Enforcement p_enforcement, int p_initializedAggregates){
        if(p_enforcement == null || p_initializedAggregates <= 0){
            return;
        }
        
        try{
            if ((p_initializedAggregates & VIOLATIONS_TYPES) > 0) {
                Hibernate.initialize(p_enforcement.getViolationTypes());
            }

            if ((p_initializedAggregates & RELIEFS) > 0) {
                Hibernate.initialize(p_enforcement.getReliefs());
            }

            if ((p_initializedAggregates & DEFENDANTS_RESPONDANTS) > 0) {
                Hibernate.initialize(p_enforcement.getDefendantRespondants());
            }

            if ((p_initializedAggregates & ENVIRONMENTAL_JUSTICES) > 0) {
                Hibernate.initialize(p_enforcement.getEnvironmentalJustices());
            }
        }catch(HibernateException e){
           //do something
        }
    }
}

I happened to write one for each of our major data model components as we only have 6 or so of them, but this model could fairly easily be generalized if you had a whole lot POJOs to deal with like this.