I Need a scheduler in java that shares a threadpool with other schedulers

Question

I have stacked for weeks trying to find a solution on this. Im coming back over and over again to the same. Java 's ScheduledThreadPoolExecutor alternatives... but nothing does this.

What I want is to execute jobs syncrhonized/serially inside a scheduler, having lot of schedulers doing that independentely from each other, backed by one single threadpool...

I have a server application in java and what I need is to create hundreds and thousands of schedulers.

I want each scheduler to execute its jobs serially and syncrhonized.

All schedulers can run concurrently and independently but I also need to limit the number of the threads of all schedulers by using a threadpool (not threadpool per scheduler, but one threadpool for ALL schedulers!). Also the ability to pause/resume jobs and put them inside groups would be great. any solutions? thanks in advance!

Answer 1

If you want jobs to execute serially within a ScheduledThreadPoolExecutor you just create an aggregated job who perform each of the actual jobs in a serial fashoin and submit it to your ScheduledThreadPoolExecutor. Though if you need thousands of schedulers to run at the same time, but still limit the no. of threads , you could get in trouble - atleast if the jobs takes too long to execute so you start slipping on your scheduling.

I'd say you should take a look at Quartz for handling this, as it'll handle most of the gory details of scheduling and jobs.

Answer 2

I'm trying to find such a solution myself. In the .Net world, you have a centrally shared thread pool provided by the system, which dynamically expands and shrinks. My situation is that I have lots of low frequency maintenance type of jobs, a single thread should be able to handle them all.

I guess you can have a singleton Executor (thread pooled version) somewhere and always use it to schedule tasks. This would mimic .Net behavior.

Answer 3

Have you considered using HawtDispatch and a lot of serial queues? It sounds like it might do as you want, with a simple API. I have been thinking of trying it myself. Akka project uses it as I understand it.

Answer 4

Maybe a separate scheduler such as Quartz Scheduler would server your needs?

Answer 5

dhtmlx scheduler works for me but this work with his own connection with db here is source and samples http://dhtmlx.com/docs/products/dhtmlxScheduler/index.shtml?mn and his java connector www.dhtmlx.com/x/download/regular/dhtmlxConnector_v09_java.zip