Mailing-List: contact commons-user-help@jakarta.apache.org; run by ezmlm
Date: Mon, 9 Dec 2002 19:00:23 +0000
Subject: Re: [betwixt] info on .betwixt files, "add" methods,
 and CyclicReferenceExceptions
Content-Type: text/plain; charset=US-ASCII; format=flowed
Mime-Version: 1.0 (Apple Message framework v482)
From: robert burrell donkin <robertburrelldonkin@blueyonder.co.uk>
To: "Jakarta Commons Users List" <commons-user@jakarta.apache.org>
Content-Transfer-Encoding: 7bit
In-Reply-To: <1039437036.5201.41.camel@swami>
Message-Id: <78A86DE9-0BA8-11D7-8C4D-003065DC754C@blueyonder.co.uk>

On Monday, December 9, 2002, at 12:30 PM, Martin van den Bemt wrote:

> On Sat, 2002-12-07 at 21:10, Darren Scott wrote:

<snip>

>> 3) I seem to get CyclicReferenceExceptions when I don't expect to. Maybe
>> it's my misunderstanding of what a graph cycle is, but I took it to mean
>> when you get into an infinite cycle with references e.g. A refers to B,
>> B refers to C, C refers to A, A refers to B etc. I get these exceptions
>> raised when I have a collection containing multiple references to the
>> same object. I wouldn't have expected this situation to be treated as a
>> cycle.
>
> The cyclic checking isn't that advanced yet. The scenario that A refers
> to another A is covered however. Since the cyclic stuff also has some
> relation when you use id's (and I am not into id's that much), I
> probably have to have some help with the id handling.
> Time to read some specs on that :)

yeh. i've been wanting to improve this for some time now.

your understanding of a cyclic graph is correct. the problem is that at 
the moment, betwixt is pretty dumb and will throw a cycle reference 
exception if it encounters the same bean if id's aren't been written.

i have played about with various ways of improving the situation but they'
ve all proved unsatisfactory. probably the basic betwixt design needs to 
be improved.

martin - if you've got some cycles, maybe we could throw ideas around.

- robert