how to return a list of objects from arraylist when passed two dates in java? [duplicate]

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Am using following code to return photo objects from arraylist between start and end date (dates are in YYYY-MM-DD string format). if no such objects, it should return empty list.

How can i modify to get the result? There are two parts of code. Here is the first part:

public class Photo {
private String title;
private string date;

public String getTitle()
return title;


public String getDate()
return date;



Here is the second part:

import java.util.ArrayList;

public class Album {

private String albumtitle;
private ArrayList<Photo> photos;
public ArrayList<Photo> datedPhotos(String date1, String date2)
String startdate = date1;
String enddate = date2;
ArrayList<Photo> photolist = new ArrayList<>();
for (Photo pho : photos)
if (pho.getDate().compareTo(enddate)< 0 && pho.getDate().compareTo(startdate)>0)
photolist.add(pho);


return photolist;
`


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3 Answers
3

You need to convert your String into dates, so that the dates can be compared. You can use the SimpleDateFormat to achieve the same. After conversion you need to check whether the date of each photo is after the startDate and before the endDate.

String

SimpleDateFormat

startDate

endDate

public ArrayList<Photo> datedPhotos(String date1, String date2)
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
ArrayList<Photo> photolist = new ArrayList<>();
Date startDate, endDate;

try
startDate = sdf.parse(date1);
endDate = sdf.parse(date2);
List<Photo> photos = new ArrayList<>();

for (Photo pho : photos)
if (startDate.before(pho.getDate()) && endDate.after(pho.getDate()))
photolist.add(pho);


catch (ParseException e)
// Handle Exception accordingly


return photolist;



SimpleDateFormat

java.time

DateTimeFormatter

try-catch

Date

startDate.before(pho.getDate())

startDate.compareTo(pho.getDate()) < 0

Date

Comparable

remove return photolist; in if statement because you return arraylist with 1 element that is first found

return photolist;

arraylist

also you are comparing startDate and endDate that method got. I think you are trying to do something like this for with you need getter

startDate

endDate

getter

if(startdate.compareTo(pho.getStartDate())< 0)


I imagine your photo object has a property called 'date'. So I think you would want something like this to add photos to your ArrayList

import java.util.ArrayList;

public class Album {

private String albumtitle;
private ArrayList<Photo> photos;
public ArrayList<Photo> datedPhotos(String date1, String date2, ArrayList(Photo) photos)
String startdate = date1;
String enddate = date2;
//edit - you actually do not need to cycle through the arraylist.....
if (photos.date.compareTo(enddate)< 0 && photos.date.compareTo(startdate) > 0)
photolist.add(pho);

return photolist;
`


And then some other place in your code you would have:

Alblum ab = new Album();
ArrayList<photo> myPhotos;
Photo newPhoto = new Photo();
newPhoto.image = "mypicture.jpg";
newPhoto.date = new Date('........');
startdate = new Date('.........');
enddate = new Date('.........);
myPhotos = ab.datedPhotos(startdate, enddate, newPhoto);


Now you have an ArrayList of type photo with one photo in it provided the date fell within the defined parameters.

compareTo(Date anotherDate)

Date

String