Indexed collection + 'cannot access loading collection'

designuk · **Posted:** Mon Dec 13, 2004 1:21 pm

Hi,

I have a problem which causes a 'cannot access loading collection' error. I believe the problem is more to do with the approach I'm taking than a bug, coding or configuration error.

It is very similiar to the problem mentioned on the following page: http://www.hibernate.org/74.html#A28.

Yet is caused when I try to implement the technique described in this article:
http://www.hibernate.org/193.html.

I have code in one of my 'child' objects which access a collection maintained by the parent object. The code looks a like this:

Code:

public int getIndex() {
    return this.getParent().getChildren().indexOf(this);
}

This method is being called when my collection is being lazily initialised and causes Hibernate to complain that I'm trying to access the loading collection, which is fair enough.

My question is: How else can I maintain the index value in a similar fashion?

Thanks in advance.

(i have excluded information about my environment as I believe this is a technique rather than a technical problem)

anthony · **Posted:** Mon Dec 13, 2004 1:40 pm

you can map the index column as a read only property

this is to used only with persistent element of the collection (not unsaved)

designuk · **Posted:** Mon Dec 13, 2004 2:06 pm

Anthony,

I believe that is what I've done already. See code below:

Quote:

public int getSeq() {
return getParent().getChildren().indexOf(this);
}

private void setSeq(int seq) {
// do nothing
}

However, I don't think this is what's causing the problem.

I encountered the problem when I added <cache usage="read-write"/> into my mapping file. I'm trying to improve overall performance by enabling caching as much as possible.

When I run a debugger against my application I can see that Hibernate reads all the properties for an object in net.sf.hibernate.impl.CacheEntry.disassemble() whilst caching the object. One of my properties calls it's parent and this is where I get the 'cannot access loading collection' message.

I want to cache this object whilst still following the same technique (described in http://www.hibernate.org/193.html).

Do you have any further ideas? Thanks.