Question

for some reason, I am unable to figure how to code it in a clean way.
I have a task object and this object has a start date and end date. I want to pass this object to method that will take this task, clone it X number of times according to the frequency and set its start date to the occurance date.

Offcourse, things can be much better illustrated by examples:
So lets say I have task that has start date of June 1 ,2012 and end date of September 15, 2012. The frequency is set to monthly. I want to pass this task to a method that would create an array of 4 tasks for me (June, July, Aug, September) of whose the start date is set to the first of the respective month

ArrayList<task> spawnTasks(Task task, Frequency Monthly){
    ArrayList<Task> arr  = new  ArrayList<Task>();

    Task TaskJune = task.clone();
    TaskJune.setStartDate("June, 1, 2012");       

    Task TaskJuly = task.clone();
    TaskJuly.setStartDate("July, 1, 2012");     

    Task TaskAug = task.clone();
    Taskaug.setStartDate("Aug, 1, 2012");     

    Task TaskSept = task.clone();
    TaskSept.setStartDate("Sept, 1, 2012");     

}

So as you can see I created the task once a month because frequency is monthly ( I can have biweekly or monthly only) and it happened on the 1st because thats the start date and it never exceeded september because the enddate is sept 15.

I know I have to use Calendar and loop to do it but I just can’t figure it out

Answer 1

Try this:

private List<Task> spawn(Task original, Frequency frequency) {

    Date sd = original.getSd();
    Date ed = original.getEd();

    Calendar cal = Calendar.getInstance();
    cal.setTimeInMillis(sd.getTime());

    List<Task> tasks = new ArrayList<Task>();
    for (; cal.getTimeInMillis() <= ed.getTime(); cal.add(frequency.getFrequency(), frequency.getMultiplier())) {
        Task task = original.clone();
        task.setSd(cal.getTime());

        tasks.add(task);
    }

    return tasks;
}

public enum Frequency {

    WEEKLY(Calendar.WEEK_OF_YEAR, 1),
    BIWEEKLY(Calendar.WEEK_OF_YEAR, 2),
    MONTHLY(Calendar.MONTH, 1),
    QUARTERLY(Calendar.MONTH, 3);

    private int frequency;
    private int multiplier;

    Frequency(int frequency, int multiplier) {
        this.frequency = frequency;
        this.multiplier = multiplier;
    }

    public int getFrequency() {
        return frequency;
    }

    public int getMultiplier() {
        return multiplier;
    }

}