java (7) equivalent of .Net timespan

is there a java (7) equivalent of the .Net timespan?

or should i compare dates? i'm not sure how to subtract 1 time/date from another + get a totalminutes answer

Quote:

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Originally Posted by .paul.

is there a java (7) equivalent of the .Net timespan?

or should i compare dates? i'm not sure how to subtract 1 time/date from another + get a totalminutes answer

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Given a Date object you can get its time stamp; it's the number of milli seconds since epoch (tipically the first of January 1970); when you subtract two time stamps you get the difference in time measured in milli seconds.

kind regards,

Jos

ok thanks for replying. that looks usable.

next question: i have a variable, startTime

how would i declare that + initialize it as date + time now?

at some point in the app, i also need to increment startTime by 1 hour.
can you help with that?

thanks for the help so far

Quote:

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Originally Posted by .paul.

i have a variable, startTime

how would i declare that + initialize it as date + time now?

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What type of variable is startTime?

i did some research + resolved this now:

//create new date = now
startTime = new Date();

//add 1 hour to date
startTime = new Date(startTime.getTime() + 1 * 60 * 60 * 1000);

ok, so far so good.

how do i get a timestamp from a date?

RESOLVED. thanks

Quote:

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Originally Posted by .paul.

at some point in the app, i also need to increment startTime by 1 hour.
can you help with that?

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If your are using Joda Time you can write something like:

Code:

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import org.joda.time.DateTime;

public class TimeCalculationDemo {
    public static void main(String[] args) {
        DateTime dateTime = new DateTime();
        System.out.println("dateTime = " + dateTime);

        DateTime nextHour = dateTime.plusHours(1);
        System.out.println("nextHour = " + nextHour);
    }
}

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Quote:

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Originally Posted by wsaryada

If your are using Joda Time you can write something like:

Code:

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import org.joda.time.DateTime;

public class TimeCalculationDemo {
    public static void main(String[] args) {
        DateTime dateTime = new DateTime();
        System.out.println("dateTime = " + dateTime);

        DateTime nextHour = dateTime.plusHours(1);
        System.out.println("nextHour = " + nextHour);
    }
}

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i've noticed joda.time mentioned on the internet, but i'm a beginner with java + i'm guessing it's a 3rd party class, or an obscure feature of java that i haven't found yet.

Joda Time offers a cleaner API way to work with date and time in Java compared with the build in java.util.Date or java.util.Calender. If you are working a lot with date time manipulation you should consider using it, because it really simplify your code.

Take a look at the following tutorial: Joda-Time

I would suggest to use either JodaTime or the Calendar API.

Code:

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Calendar cal = Calendar.getInstance();
cal.add(Calender.HOUR_OF_DAY, 1);

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i used Dates in this particular case, as they were better suited to the application.

but i also created a java TimeSpan class:

Code:

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package javaTimeSpans;

/**
 *
 * @author Paul
 */
public class TimeSpan {
   
    private int _days;
    private int _hours;
    private int _minutes;
    private int _seconds;
   
    public int Days(){
        return this._days;
    }
    public void SetDays(int d){
        this._days = d;
    }
   
    public int Hours(){
        return this._hours;
    }
    public void SetHours(int h){
        this._hours = h;
    }
   
    public int Minutes(){
        return this._minutes;
    }
    public void SetMinutes(int m){
        this._minutes = m;
    }
   
    public int Seconds(){
        return this._seconds;
    }
    public void SetSeconds(int s){
        this._seconds = s;
    }
   
    public TimeSpan(int d, int h, int m, int s){
        this._days = d;
        this._hours = h;
        this._minutes = m;
        this._seconds = s;
    }
   
    public TimeSpan(int h, int m, int s){
        this._days = 0;
        this._hours = h;
        this._minutes = m;
        this._seconds = s;
    }
   
    public Boolean Equals(TimeSpan ts){
        return this.Days() == ts.Days() && this.Hours() == ts.Hours() && this.Minutes() == ts.Minutes() && this.Seconds() == ts.Seconds();
    }
   
    public TimeSpan Add(TimeSpan ts){
        int s = this.Seconds() + ts.Seconds();
        int m = this.Minutes() + ts.Minutes();
        int h = this.Hours() + ts.Hours();
        int d = this.Days() + ts.Days();
       
        if(s > 59){
            s -= 60;
            m += 1;
        }
        if(m > 59){
            m -= 60;
            h += 1;
        }
        if(h > 23){
            h -= 24;
            d += 1;
        }
       
        return new TimeSpan(d,h,m,s);
       
    }
   
    public TimeSpan Subtract(TimeSpan ts){
        int s1 = this.Seconds();
        int m1 = this.Minutes() * 60;
        int h1 = this.Hours() * 60 * 60;
        int d1 = this.Days() * 24 * 60 * 60;
       
        int s2 = ts.Seconds();
        int m2 = ts.Minutes() * 60;
        int h2 = ts.Hours() * 60 * 60;
        int d2 = ts.Days() * 24 * 60 * 60;
       
        int sd = (s1+m1+h1+d1) - (s2+m2+h2+d2);
       
        int d = sd / (int)(24 * 60 * 60);
        sd -= (d * (24 * 60 * 60));
        int h = sd / (int)(60 * 60);
        sd -= (h * (60 * 60));
        int m = sd / 60;
        int s = sd - (m * 60);
       
        return new TimeSpan(d,h,m,s);
       
    }
   
    public int TotalHours() {
        return (this.Days() * 24) + this.Hours();
    }
   
    public int TotalMinutes() {
        return (((this.Days() * 24) + this.Hours()) * 60) + this.Minutes();
    }
   
    public int TotalSeconds() {
        return (((((this.Days() * 24) + this.Hours()) * 60) + this.Minutes()) * 60) + this.Seconds();
    }
   
    @Override public String toString() {
        if(this.Days() != 0){
            return String.format("%d:%02d:%02d:%02d", this.Days(),this.Hours(),this.Minutes(),this.Seconds());
        }
        else {
            return String.format("%02d:%02d:%02d", this.Hours(),this.Minutes(),this.Seconds());
        }
    }
   
}

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I would make the class immutable.

Quote:

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Originally Posted by .paul.

ok thanks for replying. that looks usable.

next question: i have a variable, startTime

how would i declare that + initialize it as date + time now?

at some point in the app, i also need to increment startTime by 1 hour.
can you help with that?

thanks for the help so far

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Hi,
to get date and initialize to now you can make Date d = new Date();
if you want to add to time then you need to create Calendar (java.util.Calendar)
Calendar cal = Calendar.getInstance(); (cal is set to now), if you need to set to different time you need to enter
cal.setTime(d); where d is Date (java.util.Date). If you want to add hours you need to do this
cal.add(Calendar.HOUR, 1); (there are also Calendar.MONTH, Calenda.MINUTE, ... etc)
if you want so subtract then make add with minus sign, cal.add(Calendar.HOUR, -1);
finally to get date from calendar just put Date calculatedDate = cal.getTime();

Code:

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import java.util.Calendar;
import java.util.Date;

public class test {
        public static void main(String[] args) {
                // creates calendar from now
                Calendar cal = Calendar.getInstance();
                // you can add, minutes, seconds, days, etc ..
                // to subtract add with minus
                cal.add(Calendar.MINUTE, 1);
               
                Date d = cal.getTime();
        }
}

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