CODEWITHSUNDEEP
javaperformancedatetimejodatime
ccpmark
ccpmark

Reputation: 1005

What is the least expensive java Joda DateTime update method?

I'm looking to update the time for DateTime object. I've noticed that there are two different methods for creating a copy of a DateTime object with an updated time, but I'm not sure which to use.

Is there an advantage of using one of these over the other?

import org.joda.time.DateTime;

DateTime oldTime = DateTime.now()
newTime = oldTime.withMinuteOfHour(30)

versus

import org.joda.time.DateTime;

DateTime oldTime = DateTime.now()
newTime = oldTime.minuteOfHour.setCopy(30)

Upvotes: 0

Views: 180

Answers (2)

Rohit Jain
Rohit Jain

Reputation: 213233

Talking about performance - I don't really bother much, because those 3 lines is almost never going to be a bottleneck in your application unless you're dealing an extreme memory intensive application, where a single extra object might be much of a deal. (Just so you know, I went to the source code, and found out, second approach created an extra Property object)

Talking about readibility - certainly I would go with 1st one. Because I've to go to the API to see what setCopy() does. First one clearly shows the intent, that it is request a new DateTime object, with minuteOfHour set to the passed value.

Here's another reason why I would not prefer the 2nd approach. The minuteOfHour() method returns a Property:

Property minuteOfHour = date.minuteOfHour();

Now that property can be assigned to any property of date. I can later on do:

minuteOfHour = date.dayOfYear();

That would compile, but changes the meaning of variable without actually changing the name. That means, you won't really know what property you're setting to when you call: Property#setCopy().

Upvotes: 2

farrellmr
farrellmr

Reputation: 1905

They are probably about the same - here is the source code for withMinuteOfHour - 

public DateTime withMinuteOfHour(int minute) {
        return withMillis(getChronology().minuteOfHour().set(getMillis(), minute));
}

While minuteOfHour is -

public Property minuteOfHour() {
            return new Property(this, getChronology().minuteOfHour());
}

So the core of the calls are the same

Upvotes: 1

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