How to sort JTable in shortest way?

Question

I was searching for Sorting in JTable and I referred many articles, but couldn't get the easiest way to sort the table. I also know that TableRowSorter could be somehow helpful but don't know how. Being new to JTable, I am creating a new question here.

My table structure is something like this

| People  | Place |   Organisation    | Event    | Mentions |
_____________________________________________________________
| Ramanuj | India | Tata Consultancy  | Party'14 |  500000  |
| Prankster | USA | Microsoft Pvt Ltd | Party'14 |  900000  |

---

What I want here is to sort my table Descending based on 4th column ("Mentions"). If counts (Mentions) are same, it should sort Ascending by 1st column ("People")

CSVReader reader = new CSVReader(new FileReader(file)); 

List<String[]> myEntries = reader.readAll();
String[][] rowData = myEntries.toArray(new String[0][]);

String[] columnNames = { "People", "Place", "Organisation", "Event", "Mentions" };

DefaultTableModel tableModel = new DefaultTableModel(rowData, columnNames);

Defilade

Answer 1

As per How to Use Tables: Sorting and Filtering

JTable table = new JTable(tableModel);
TableRowSorter<TableModel> sorter = new TableRowSorter<TableModel>(table.getModel());
table.setRowSorter(sorter);

List<RowSorter.SortKey> sortKeys = new ArrayList<>(25);
sortKeys.add(new RowSorter.SortKey(4, SortOrder.ASCENDING));
sortKeys.add(new RowSorter.SortKey(0, SortOrder.ASCENDING));
sorter.setSortKeys(sortKeys);

Updated

Are you sure it will sort?

...Yes

import java.awt.EventQueue;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.RowSorter;
import javax.swing.SortOrder;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
import javax.swing.table.TableRowSorter;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                DefaultTableModel model = new DefaultTableModel(new String[]{"People", "Place", "Organisation", "Event", "Mentions"}, 0);
                model.addRow(new Object[]{"Prankster", "USA", "Microsoft Pvt Ltd", "Party'14", 900000});
                model.addRow(new Object[]{"Ramanuj", "India", "Tata Consultancy", "Party'14", 500000});
                model.addRow(new Object[]{"Banana", "India", "Tata Consultancy", "Party'14", 500000});

                JTable table = new JTable(model);
                TableRowSorter<TableModel> sorter = new TableRowSorter<TableModel>(table.getModel());
                table.setRowSorter(sorter);

                List<RowSorter.SortKey> sortKeys = new ArrayList<>(25);
                sortKeys.add(new RowSorter.SortKey(4, SortOrder.ASCENDING));
                sortKeys.add(new RowSorter.SortKey(0, SortOrder.ASCENDING));
                sorter.setSortKeys(sortKeys);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

}

Updated

You can extract the data from the view directly...

 for (int row = 0; row < table.getRowCount(); row++) {
     String people = table.getValueAt(row, 0).toString();
     String place = table.getValueAt(row, 1).toString();
     String organisation = table.getValueAt(row, 2).toString();
     String event = table.getValueAt(row, 3).toString();
     int mentions = (int)table.getValueAt(row, 4);
     //...
 }

This will give you the data in the "view" (or sorted) order...

Gunner

Are you sure it will sort? Cause I tried just for my column 4, keeping DESCENDING, and checked TableModel. Its still same. Do I need to refresh or something? – Defilade

Yes. But beware, sorting a String (that represents a number) and sorting an actual number will give different results... – Gunner

I am checking hovering on model variable. Its same there. Won't it reflect there? If not where can I see updated one? – Defilade

No, sorting is done at the view level ONLY, it does not affect the model at all, this is the point and a very important one – Gunner

But I want to export updated Table in new csv. So how? – Defilade

Create a Plain Old Java Object (POJO) which is a representation of a single row of your data. Parse the CSV file, creating a POJO for each row, place them into a List of some kind and use Collections.sort to sort them, using a custom Comparator. See Collections Trail for more details – Gunner

Also, with respect, understand that your question is about how to sort a JTable, it didn't mention all these other requirements... – Gunner

Arr... That's why I say, I don't find an easiest way :( Can you update your answer so that it can change sorting in model itself ? – Defilade

Not until you change the question so it asks the appropriate, detailing what it is you are trying to achieve and what it is you have tried... – Gunner

With respect, I asked to sort the table, Didn't ask to make it sorted in just view part. If you can't please don't. – Defilade

And the table is sorted...The meaning of communication is defined by the receiver, with respect, if you can't ask a clear question, then don't expect a clear answer... – Gunner

I was about to be thankful to you, but I feel people like you cant respect stackoverflow portal. Thanks for all your help. If you are here just to gain votes, here I can give to you. Bye. tc – Defilade

With all due respect, I can only answer the question that you ask. You made no mention that you wanted the data sorted or that you wanted to save the data after the fact until AFTER I had provided a answer. I would love to help you, but you need to understand that the answers MUST reflect the question, otherwise other people who might be looking for helping sorting a JTable may get the WRONG answer, because you've failed to provide appropriate context to the question. Before you start blaming other people, who are voluntarily trying to help, accept portion of the blame in the correct ratio – Gunner

ps- I asked you to update THIS question to reflect your needs, not ask another one ;) – Gunner

Thanks bro, but I just copied model data to new csv by looping. But thanks a lot for your help. You don't know how much time you saved of mine. Thanks again. :) – Defilade

If you can update the question a little, stating your want to sort the data/save it for later, I can add another way to sort the data... – Gunner

Thanks bro for adding extra details :) – Defilade

I hope it all helps in some small way ;) – Gunner

Answer 2

Try to use this

table.setAutoCreateRowSorter(true);

Cadelle

Can you expand your answer a little bit, please? Maybe add some introductory text, a link to the JavaDoc and cite the relevant passage. Also formatting the example code would be nice (just add at least 4 spaces before each line of code). – Graniteware

(1-) This only allows the user to click on a column header to sort by the column. It does not automatically sort on the 4th column as per the requirement of this question. – Orjonikidze