Scheduling a job with Spring programmatically (with fixedRate set dynamically)
java, scheduled-tasks, spring, spring-annotations, spring-scheduled
Solution
Using a `Trigger` you can calculate the next execution time on the fly.
Something like this should do the trick (adapted from the Javadoc for `@EnableScheduling`):
@Configuration
@EnableScheduling
public class MyAppConfig implements SchedulingConfigurer {
@Autowired
Environment env;
@Bean
public MyBean myBean() {
return new MyBean();
}
@Bean(destroyMethod = "shutdown")
public Executor taskExecutor() {
return Executors.newScheduledThreadPool(100);
}
@Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
taskRegistrar.setScheduler(taskExecutor());
taskRegistrar.addTriggerTask(
new Runnable() {
@Override public void run() {
myBean().getSchedule();
}
},
new Trigger() {
@Override public Date nextExecutionTime(TriggerContext triggerContext) {
Calendar nextExecutionTime = new GregorianCalendar();
Date lastActualExecutionTime = triggerContext.lastActualExecutionTime();
nextExecutionTime.setTime(lastActualExecutionTime != null ? lastActualExecutionTime : new Date());
nextExecutionTime.add(Calendar.MILLISECOND, env.getProperty("myRate", Integer.class)); //you can get the value from wherever you want
return nextExecutionTime.getTime();
}
}
);
}
}
Problem
Currently I have this : ``` @Scheduled(fixedRate=5000) public void getSchedule(){ System.out.println("in scheduled job"); } ``` I could change this to use a reference to a property ``` @Scheduled(fixedRateString="${myRate}") public void getSchedule(){ System.out.println("in scheduled job"); } ``` However I need to use a value obtained programmatically so the schedule can be changed without redeploying the app. What is the best way? I realize using annotations may not be possible...