1. An eclipse client server architecture
with asynchronous messaging
based on XMPP
Thomas Kratz
EclipseCon Europe 2011

2. What is XMPP?
• eXtensible Messaging and Presence Protocol
• Bi-directional streaming XML
• Core: IETF RFC 3920, 3921
• Extensions: XMPP Standards Foundation (XSF)
– Membership-based
– Elected technical council
– Unit of work: XMPP Extension Protocol (XEP)
– Process: Experimental, Proposed, Draft, Final
• Goals:
– Simple clients
– Federate everything

3. XMPP Architecture
• Addressing Scheme: node@domain/resource
– JID = Jabber ID
– Node: identity, e.g. user name
– Domain: DNS domain name
– Resource: device identifier
– node@domain identifies a person
• Client talks to “local” server
– Wherever the user account is hosted
– Tied to directory if desired
– Organizational policy enforced
• Servers talk to other servers
– DNS lookup on domain portion of address
– Dialback, MTLS for security
– One connection for many conversations

4. The Mango stack
Client
Synchronous remote Asynchronous
service calls notifications
through Spring‘s through Smack
HttpInvoker XMPP Api
Server

5. Long running tasks
• http-service call spawns a worker thread on
the server and returns immediately
• Client UI runs a fake worker job (Eclipse Jobs
API) that listens to XMPP messages
• Worker Thread reports progress to client Job
through XMPP messages
• Client Job fetches result through second http-
service call

6. Not so optimistic
locking
• Eclipse Editor lifecycle sends XMPP messages
on open/save/close
• Server keeps track of opened database
entities
• Sends warning on possible conflict
• If an enitity gets changed, other users get
notified to reload their editor input to prevent
conflicts.

7. Floating Licene
• Server listens to the „Presence“ part of the
XMPP protocol
• Keeps track of online users
• Rejects login if maximum user count is
exceeded
• Notifies online users before server shutdown
to prevent data loss.

8. Q&A
• Thank you for listening!
• Reach me at eiswind@googlemail.com