Getting previous instant with given time of day - java-8

Question

I have a wake-up time at 7:45. I want my code to return the previous moment in time when this was the local time (ie. the previous wake-up time)
I know I can do this:
LocalTime wakeUpTime = LocalTime.of(7, 45);
ZonedDateTime now = ZonedDateTime.now();
ZonedDateTime todaysWakeUpTime = now.with(wakeUpTime);
ZonedDateTime lastWakeUpTime;
if(todaysWakeUpTime.isAfter(now)){
// e.g. it is now 4:30, so wake-up is still to come,
// return the one from yesterday
lastWakeUpTime = todaysWakeUpTime.minusDays(1);
} else {
// e.g. it is now 11:30, so wake-up for today is already past
lastWakeUpTime = todaysWakeUpTime;
}
System.out.println(lastWakeUpTime);
Is there a cleaner version, e.g. using temporal adjusters, which better conveys the intent (getting the last of these times)?

Answer 1

A TemporalAdjuster can be written that allows the code to read as:
LocalTime wakeUpTime = LocalTime.of(7, 45);
ZonedDateTime now = ZonedDateTime.now();
ZonedDateTime lastWakeUpTime = now.with(previousTime(wakeUpTime));
Somewhere you need to write a static method that implements the adjsuter:
public static TemporalAdjuster previousTime(LocalTime time) {
return temporal -> {
// logic to find the previous occurrence of the time
};
}
Implementing the logic will require decisions around what to do when the input is different kinds of temporals, eg LocalDate (no time, so can't work), LocalTime (no date, so nothing earlier), ZoneDateTime (what about DST changes), Instant (no date or time without a time-zone).

Answer 2

Based on the #JodaStephen 's answer (thanks!), here is my adjuster (for reference):
public static TemporalAdjuster previousTime(LocalTime time){
return (temporal) -> {
if (temporal instanceof ZonedDateTime) {
ZonedDateTime zdt = (ZonedDateTime) temporal;
ZonedDateTime newTime = zdt.with(time);
if(newTime.isAfter(zdt)){
newTime = newTime.minusDays(1);
}
return newTime;
} else {
throw new DateTimeException("This adjuster only handles ZonedDateTime");
}
};
}