Java Community | Help. Code. Learn.•2mo ago

instance

public class CooldownManager {
    private final Map<UUID, Instant> map = new HashMap<>();

    // Set cooldown
    public void setCooldown(UUID key, Duration duration) {
        map.put(key, Instant.now().plus(duration));
    }

    // Check if cooldown has expired
    public boolean hasCooldown(UUID key) {
        Instant cooldown = map.get(key);
        return cooldown != null && Instant.now().isBefore(cooldown);
    }

public class CooldownManager {
    private final Map<UUID, Instant> map = new HashMap<>();

    // Set cooldown
    public void setCooldown(UUID key, Duration duration) {
        map.put(key, Instant.now().plus(duration));
    }

    // Check if cooldown has expired
    public boolean hasCooldown(UUID key) {
        Instant cooldown = map.get(key);
        return cooldown != null && Instant.now().isBefore(cooldown);
    }

I was reading on how to make a cooldown when i stumbled across this block of code. I was asking myslef if the last line should be

!Instant.now().isBefore(cooldown);

!Instant.now().isBefore(cooldown);

since without it, we would be checking if the current time is before cooldown (which we dont) so we should neagte that. right?

10 Replies

JavaBot•2mo ago

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dan1st•2mo ago

the current code without the negation is checking if the current time is before the cooldown in other words if the cooldown ends in the future (or now) i.e. it is active if it ends in the future

FRG•2mo ago

hello the method name hasCooldown isn't clear enough imo id name it isCooldownEpired

dan1st•2mo ago

world That's the opposite of what the method is currently doing

FRG•2mo ago

ye they can reverse the return value. im looking for a way to make it more readable

dan1st•2mo ago

hasCooldown <-> hasActiveCooldown <-> is the current time before the expiration time of the cooldown <-> Does the cooldown expire in the future? if they care about equality ("the cooldown should still be active in the last millisecond of the cooldown"), that would change behavior there is isBefore and isAfter but if you want isAfterOrEqual, you'd need to use isBefore and switch the receiver and parameter

FRG•2mo ago

i think that the word "cooldown" is not suitable to this imo it refers to a number of seconds like 10, 5, 2 it would be better to say timeout now().isBefore(timeout) it makes sense this way ig

dan1st•2mo ago

tbh I'd say it's fine, especially if it's also called cooldown in interactions with other systems (e.g. telling the user) But I'd just wait for the question author - I think discussing these things without the doesn't make much sense

FRG•2mo ago

got it

JavaBot•2mo ago

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