Hi Henry, All communication from controller to participant is modeled as a state transition. So you create a resource with partitions and replicas to follow a state model, and you will automatically get callbacks when it's time to transition.
The hope is that you use the built-in helix controller and push app logic to participants/spectators. That way, the controller can just tell participants what to do in the form of a transition, and the participant decides what that means. Does that make sense? Kanak > Date: Sun, 23 Mar 2014 09:12:33 -0700 > Subject: Re: Update: New Helix API's > From: [email protected] > To: [email protected] > > Quick question, how do you fire event from controller to participants? > > - Henry > > On Sat, Mar 22, 2014 at 2:09 PM, kishore g <[email protected]> wrote: > > Hi, > > > > Thanks to Sandeep and Kanak we are getting close to having the new > > helix-api package. > > > > https://github.com/kanakb/helix > > > > Here is the api package > > https://github.com/kanakb/helix/tree/master/helix-api/src/main/java/org/apache/helix/api > > > > Feedback/suggestions? > > > > > > Before we get started working on the roles (administrator, participant, > > controller, spectator), we need to wrap up the constraints api. > > > > At a high level we have state & transition constraints at cluster, > > participant, resource, partition granularity. > > > > We have two options > > > > #1 Have a separate package called constraints and have > > (cluster|participant|resource|partition)Constraint. > > > > #2. Have StateConstraint & TransitionConstraint as attributes in > > (cluster|participant|resource|partition)configuration. > > > > Thoughts. > > > > > > thanks, > > Kishore G
