in src/main/java/org/apache/sling/commons/scheduler/impl/QuartzScheduler.java [510:519]
public ScheduleOptions EXPR(final String expression) {
if ( expression == null ) {
return new InternalScheduleOptions(new IllegalArgumentException("Expression can't be null"));
}
if ( !CronExpression.isValidExpression(expression) ) {
return new InternalScheduleOptions(new IllegalArgumentException("Expressionis invalid : " + expression));
}
return new InternalScheduleOptions( TriggerBuilder.newTrigger()
.withSchedule(CronScheduleBuilder.cronSchedule(expression)));
}