Re: JavaClient offline storage / replication
Re: JavaClient offline storage / replication
- Subject: Re: JavaClient offline storage / replication
- From: Anjo Krank <email@hidden>
- Date: Fri, 17 Apr 2009 16:20:00 +0200
Am 17.04.2009 um 15:59 schrieb Jean-Francois Veillette:
My original task was to sync 2 sites using - get this - email (No,
I couldn't use anything else, it HAD to be email). I ended up with
using JMS to halfway maintain queue integrity. It actually worked
and because each site only had their own change sets with their own
PKs (this is what the host flag in ERXLongPKFactory is for),
conflicts were minimal and easy to sort out. But it was still a
nightmare and I'm glad they now listened to reason :)
Very interesting ! Nice to see someone actually build a solution
for this kind of problem !
I'm currious, do you have an automated mail reader that
automatically 'import' change set ? does it need manual
intervention ?
Can you elaborate a little bit, just enough so I get the big picture.
A bit, as I don't care to remember this in too much detail :)
Actually, it looked like I pulled out the JMS as openJMS wasn't too
stable to begin with and used my own tiny queue implementation.
I had what you had: SyncQueue (name, messages) + SyncMessage (queue,
payload, reponse, sequence no)
Also as I had images and changes to sync, I had 6 queues:
Master:
- create one Sender for the images
- create one Sender for the master queue
- create one Receiver for the client queue
Client:
- create one Sender for the client queue
- create one Receiver for the master queue
- create one Receiver for the images
EC changes get sent into the outbound queue, then sent as mail. Client
reads items (IMAP), if it's out of order, waits until he gets the
correct number. There was an interface to resend. Client gets payload,
execs items. Last write wins, changes are merged, conflicts are
reported. Deleted are ignored. Client write receipt, master reads it
and marks the item as done ("result" as text).
The rest I can't remember (except telling them that when push comes to
shove, they have to start fresh and the whole thing is a terrible idea
to begin with)
Cheers, Anjo
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden