arturn arturn - 5 months ago 8
Java Question

Enum as key of HashTable

I'm writting a Schedule structure in Java.
I have a Hashtable with enum Day as Key and list of timeranges as value.
Like this :

public enum Day {
SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
THURSDAY, FRIDAY, SATURDAY
}

private Hashtable<Day,TimeRanges> _applyCalendar;


where TimeRanges class is ...

public class TimeRanges implements List<TimeRange> {


When I add elements to _appleCalendar I do this :

public void addApplyDay(Day day,TimeRanges trs) {
if (! _applyCalendar.contains(day)) {
_applyCalendar.put(day, trs);
} else {
for ( TimeRange t : trs) {
_applyCalendar.get(day).add(t);
}
}

}


My problem is method contains() doesn't work right.
HashTable can't be able to found existing element in hashtable,all time enter in the first condition :S

Is there any way to do this without should to declare Day as class and implement comareTo() ??

Answer

I think you want to use .containsKey() instead of contains(). contains() will search the actual objects whereas containsKey() will search the keys.

public void addApplyDay(Day day,TimeRanges trs) {
    if (! _applyCalendar.containsKey(day)) { // << use containsKey
        _applyCalendar.put(day, trs);
    } else {
        for ( TimeRange t : trs) {
            _applyCalendar.get(day).add(t);
        }
    }

}
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