Scheduler + CRON

[pkriens]

The enRoute scheduler had support for CRON. We
adopt this code.

[stbischof]

That is great!! Thank you for the fast support!

Maybe this would ve goot to have

https://github.com/aQute-os/biz.aQute.osgi.util/blob/576cb4de913d46e5c72d79b7df31d08c1771f29c/biz.aQute.api/src/main/java/biz/aQute/scheduler/api/annotation/CronExpression.java

SchedulerImpl has us the DefaultZone
Clock clock= Clock.systemDefaultZone();

We may should add an MetaTypeConfig to make the SchedulerImpl configurable.

static final String TIMEZONE_DEFAULT = "default";//or""

@interface SchedulerConfig {
	
	String timeZone() default TIMEZONE_DEFAULT;
}

//constructor

if (TIMEZONE_DEFAULT.equals(schedulerConfig.timeZone())) {
	clock = Clock.systemDefaultZone();
} else {
	clock = Clock.system(ZoneId.of(null));
}

[pkriens]

Ok, ok. Added this but you can make the test :-)