Java中多个任务的任务调度？

Question

i have build a java clock with using timer,which works fine for a single task to alarm on next given/setted time, but i am having problem in scheduling multiple tasks(alarms for diff. times) with this timer, as two times can clash each other(same times for two different works) how to synchronize between such conditions, please help....

Thanks and Regards

Alok Sharma

Answer 1

I'm not sure what you're trying to do, but if you use quartz scheduler, you can resolve just about any scheduling/synchronisation task:

http://www.quartz-scheduler.org/

Answer 2

I agree with Lukas that you can use quartz. It is the best, scalable and robust solution.

But if you need something relatively small you can continue using timer based solution. As javadoc of Timer class indicates your tasks should take very few time. In this case you can forget about time clash. If your tasks take more then 0.1 seconds run them in separate thread. I mean use Timer as a trigger that just makes task to start in separate thread.

The thread may be done as following:

1. Create thread yourself. If you are in J2EE container it is bad practice. If you are in Tomcat it is ... not so bad.
2. Use thread pool. Comments about container are relevant here too.
3. Use JMS: Timer just pushes message to JMS. MDB or its equivalent receives message and performs task.

Using Timer itsef in J2EE container is a bad practice too. If you are there and wish to be "clean" use JCA to to run Timer.