Add RFC 5545 RRULE trigger support (dependency-free implementation)

[sideeffffect]

Summary

Adds first-class support for RFC 5545 RRULE (iCalendar recurrence rules) as a scheduling option, mirroring the existing CronTrigger stack. New public API:

RRULE class	Cron analogue
RRuleExpression	CronExpression
RRuleTrigger / RRuleTriggerImpl	CronTrigger / CronTriggerImpl
RRuleScheduleBuilder	CronScheduleBuilder
RRuleCalendar	CronCalendar
RRuleTriggerPersistenceDelegate	CronTriggerPersistenceDelegate
RRuleTriggerSupport (JMX)	CronTriggerSupport

Trigger trigger = newTrigger()
        .withIdentity("myTrigger")
        .withSchedule(rruleSchedule("FREQ=WEEKLY;BYDAY=MO,WE,FR;BYHOUR=10;BYMINUTE=0"))
        .startAt(futureDate(10, MINUTES))
        .build();

Design notes

• Recurrence engine: implemented from scratch, with no third-party dependency, following the expand/limit semantics of the table in RFC 5545 §3.3.10. It was cross-validated against org.dmfs:lib-recur across a broad battery of rules and time zones (including DST transitions) to confirm equivalence on the mainstream rule set.
• DTSTART anchor: RFC 5545 defines an RRULE relative to a DTSTART. In Quartz that anchor is supplied by the trigger's mandatory startTime, exactly as a CronTrigger uses its start-time as a lower bound. Following the RFC, the start instant only fires if it actually matches the pattern.
• Persistence: a new QRTZ_RRULE_TRIGGERS table (RRULE string + time-zone) with DDL added to every vendor script under jdbcjobstore, a registered RRuleTriggerPersistenceDelegate, and a new TTYPE_RRULE discriminator. The delegate loads via its own dedicated SELECT (rather than the inlined bulk join) because the shared TIME_ZONE_ID column would collide in SELECT_BULK_TRIGGERS_BASE.
• Supports FREQ, INTERVAL, COUNT, UNTIL, WKST, BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY (incl. ordinals), BYHOUR, BYMINUTE, BYSECOND, BYSETPOS.
• Note on DST for sub-daily rules: the engine advances in absolute time, so an HOURLY rule fires once across a spring-forward transition (matching Quartz's cron behaviour) rather than emitting a duplicated wall-clock hour.

Tests & docs

• Unit tests for the expression, schedule builder, trigger and calendar, plus a Derby JDBC integration test exercising the persistence delegate end to end.
• example16 (RRuleTriggerExample) demonstrating the DSL, runnable via ../gradlew :examples:runExample16.
• Companion documentation PR: Add RRuleTrigger (RFC 5545 RRULE) tutorial for 2.5.x quartz-scheduler.org-site#123 (a "RRuleTrigger Tutorial" page).

Note

This is the dependency-free implementation. An alternative PR built on org.dmfs:lib-recur (#1498) exposed the identical public API and test suite; it has been closed in favour of this one per the discussion below.

🤖 Generated with Claude Code

[melloware]

+1 for the dependency free implementation!

[jhouserizer]

I agree with @melloware that the dependency-free version is better overall. I'll try to have a more thorough review this morning.

[jhouserizer]

@sideeffffect , I appreciate this new feature, and know that many users will.

Could I trouble you+Claude to include some docs / examples for the new trigger type? e.g.:

https://github.com/quartz-scheduler/quartz/tree/main/examples
https://github.com/quartz-scheduler/quartz-scheduler.org-site/blob/master/documentation/quartz-2.5.x/tutorials/index.md

[sideeffffect]

Thanks for the quick look, @jhouserizer and @melloware! 🙏

I've added in-repo docs/examples in 3260c72:

• example16 – an RRuleTriggerExample (analogous to example3 for cron) that schedules jobs via RRuleScheduleBuilder.rruleSchedule(...), demonstrating SECONDLY/WEEKLY/MONTHLY frequencies, ordinal BYDAY (last Friday of the month), BYMONTHDAY lists, BYDAY limiting (weekends only), and a COUNT-bounded rule.
• Wired the runExample16 Gradle task and added it to examples_guide.txt.

Run it with ../gradlew :examples:runExample16.

The tutorials page you linked lives in the separate quartz-scheduler.org-site repo, so it can't be part of this PR. I'm happy to open a companion PR there (a "RRULE Triggers" tutorial section mirroring the CronTrigger tutorial) once you've settled on which of the two implementations (#1499 dependency-free vs #1498 lib-recur) you'd like to take — just say the word and I'll get it drafted.

[sideeffffect]

Docs are up as well: I opened a companion tutorial PR against the site repo — quartz-scheduler/quartz-scheduler.org-site#123 (a "RRuleTrigger Tutorial" page mirroring the CronTrigger one, linked from the 2.5.x tutorials index).

[sideeffffect]

Hello @jhouserizer , thanks for looking at this. Please let me know if there's anything more I can do 🙏

[sideeffffect]

ping 😸 @melloware @jhouserizer