I want to implement status-information in our POJO like isNew or hasChanged.

The remaining open issue is how to make the POJO recognizing when hibernate injects an existing object from db.
Per default hibernate uses default contructor and calls the setters. No chance here set the flag.

Q: How can I tell hibernate to use a given contructor (e.g. passing all props there) instead of the default constructor ?
This way I could set the flag in the POJO.

/m

Is it a new or legacy database? If it's a new database, you could add the flag as a column.

Or better yet (and this is off the top of my head), let hibernate use the default constructor, and the application, when first creating a transient object use a different constructor.

When you think about it, even though hibernate uses the default constructor, the flag for any object retrieved from the database would automatically be true... so your default constructor could set it.

And since you'd be creating any transient object, you could just use a constructor where you pass it a value to set the flag false.

theoretically this would work, but can hardly enforce that application developers don't use the default constructor. They will use it.

There is no other way but telling hibernate to use a given special constructor.

How to do this?

Interceptor.instantiate

and create it with a constructor that sets your flag...

ok, great. but what do I do with the given Serializable id ?
If I ignore it it results in trouble with id-idfentification.

you put it in your id field

err - good point, but what if there is a composite-id ?
What I need is a hibernate service-method that injects the Serializable id into the newly created POJO.

also, in case the key is identical with a property, the name of the property differs.
Hence the id can only be set using the info from the mapping-file. Hibernate should do the job. Just how?

if you know which constructor to call, why don't you know which property is the id ?

..and anyhow look at ClassMetaData.setIdentifier()

thx, good hint. however this appears to work only using a static accessor to hibernate-session-factory.

eh -why is that a problem ?

you just call a method on your interceptor that can keep it around for you.