Recurring event

[Andrei Dan]

Hello!
I want my application to support recurring events.
EX: The event will be repeated every 24 hours : 2021-01-01 22:40:32  the new event start at 2021-01-02 22:40:00
I think the mistake is at  Calendar c = Calendar.getInstance();
       c.setTime(this.dataP);
       if (this.dataP.after(getDataInceput())) {
           c.add(Calendar.HOUR, numarOre);
       }

import java.text.SimpleDateFormat;
import java.util.Date;

public class Eveniment {
    private Date dataInceput, dataSfarsit;
    private String nume;

    public Eveniment(String dataInceput, String dataSfarsit, String nume) {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        try {
            this.dataInceput = format.parse(dataInceput);
            this.dataSfarsit = format.parse(dataSfarsit);
        } catch (Exception e) {
            System.out.println("Data nu este in formatul cerut!");
        }

        this.nume = nume;
    }

    public Date getDataInceput() {
        return dataInceput;
    }

    public Date getDataSfarsit() {
        return dataSfarsit;
    }

    public String getNume() {
        return nume;
    }
}


import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

class EvenimentRecurent extends Eveniment {
    private Date dataP;
    private int numarOre;


    public EvenimentRecurent(String dataInceput, String dataSfarsit, String nume, int numarOre) {
        super(dataInceput, dataSfarsit, nume);
        this.numarOre = numarOre;
    }

    private static final DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    public String urmatorulEveniment(String dataP) {
        //Date neww;
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        try {
            this.dataP = format.parse(dataP);
        } catch (Exception e) {
            System.out.println("Data nu este in formatul cerut!");

        }
        Calendar c = Calendar.getInstance();
        c.setTime(this.dataP);
        if (this.dataP.after(getDataInceput())) {
            c.add(Calendar.HOUR, numarOre);
        }
        Date currentDatePlusOne = c.getTime();
        String strDate = dateFormat.format(currentDatePlusOne);
        return strDate;

    }
}


public class Main {
    public static void main(String[] args) {

        EvenimentRecurent er = new EvenimentRecurent("2019-03-09 22:46:00",
                "2019-03-09 23:00:00", "Informatics", 24);
        System.out.println(er.urmatorulEveniment("2019-04-19 22:46:23"));

        // display 2019-04-20 22:46:23 but the correct option is 2019-04-20 22:46:00
    }
}

[Campbell Ritchie]

Welcome to the Ranch

Don't use Date, nor Calendar. Use the datatypes described in this tutorial.
Will you be running your application continuously? Consider a java.util.Timer, or use a system utility like cron.

[Tim Holloway]

Welcome to the Ranch, Andrei!

While he basic Java systems has become a lot more extensive in recent years, I think probably that the Quartz Scheduler might be better suited. It's a third-party library that can is very flexible in dealing with recurring events and events on a fixed schedule. If you're using the Spring Framework, it has a scheduling module, also, including the ability for Quartz to be managed by Spring.

Also, I'm assuming that your app will be operating 24 hours a day. If you actually just need to run a Java program at a given time and/or on given days, you can use the cron facility that's standard with Unix/Linux or the Windows Scheduler on Windows.

[Norm Radder]

Also posted here: https://www.dreamincode.net/forums/topic/421013-recurring-event/

Please read:  https://coderanch.com/wiki/660346/Wiki/Forthright-Cross-Posting-Sites