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deepCopy() while implementing UserType

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chotasher

Post subject: deepCopy() while implementing UserType

Posted: Fri May 13, 2005 12:13 pm

Newbie

Joined: Sun Nov 09, 2003 12:34 pm
Posts: 15

Hi,

Hibernate gurantees that the JavaIdentity for the persistable objects in the same session is same. Relying on Java identity, the objects do not implement equals() and hashCode().

However, in case of UserTypes where deepCopy() returns a real deep copy instead of returning the same object back, Hibernate always marks that object as dirty. Our problem was resolved by returning the same object back in deepCopy()

Code:

    public Object deepCopy(Object value) {
      return value;
    }

My questions are:
- When to return the same object and when to return a copy? What are the implications of each?
- Do we need to implement hashCode() and equals() if we return copy of an object in deepCopy()?

Thanks,

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gavin

Post subject:

Posted: Fri May 13, 2005 12:20 pm

Hibernate Team

Joined: Tue Aug 26, 2003 12:50 pm
Posts: 5130
Location: Melbourne, Australia

Fix your implementation of UserType.equals(x, y)

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chotasher

Post subject:

Posted: Fri May 13, 2005 12:48 pm

Newbie

Joined: Sun Nov 09, 2003 12:34 pm
Posts: 15

Hi,

I have your book, in that it mentions that

Quote:

In case of a Mutable type, it would return a copy of the argument to be used as a snapshot value. This method is also called when an instance of the type is written to or read from the second level cache.

Are you implying that If I return a copy from deepCopy(), then I have to implement the UserType.equals(x,y) based upon the values and NOT rely on Java Identity?

Currently, my equals looks like this

Code:

    public boolean equals(Object x, Object y) {
        return ObjectUtils.equals(x, y);
    }

Thanks,

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