CODEWITHSUNDEEP
javaswingsortingjtable
user4948189
user4948189

Reputation:

Sort the contents of a JTable

I am working with a JTable That schould display Some informations sorted By the last two columns. The problem is the last two columns are filled with strings, one of them are Days of the Weak(Monday-Friday) the others are Hours(HH:mm), i would like to sort them going from Monday-Friday and if there are more elements of the same Day they schould be sorted by the Erliest Hour. Until now google was not a realy big help since it schows only ways to sorte something Alphabetically ore in Ascendant/descendant order for numbers, but i dont need an Alphabetically ordered JTable. Does anyone have an idea?

public class ScheduleFrame extends JFrame {

private JPanel contentPane;
private static JTable table;


public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                ScheduleFrame frame = new ScheduleFrame();
                frame.setVisible(true);

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 * @throws Exception 
 */
public ScheduleFrame(){
    setTitle("Schedule");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 627, 405);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    contentPane.setLayout(new BorderLayout(0, 0));
    setContentPane(contentPane);
    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);


    JScrollPane scrollPane = new JScrollPane();
    contentPane.add(scrollPane, BorderLayout.CENTER);

    table = new JTable();
    scrollPane.setViewportView(table);
    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
     table.setModel(new DefaultTableModel(
        new Object[][] {
        },
        new String[] {
            "Course Name", "Course Room","Course Day", "Course Hour"
        }
     ));}



    public static void loadTable()throws Exception{
        DefaultTableModel tm = (DefaultTableModel) table.getModel();
        BufferedReader bfw = new BufferedReader(new FileReader("Schedulecourses.txt"));
        String line;
        while( (line = bfw.readLine() ) != null ) {
        tm.addRow( line.split("\t") );
       }
          bfw.close();
       }
 }

This is how it schould look like

https://i.sstatic.net/vcgNY.png

Upvotes: 0

Views: 682

Answers (3)

Danail Alexiev
Danail Alexiev

Reputation: 7772

I suggest you try and map the data that you read from the file to some kind of a model object that you can later sort. For example:

public class Course implements Comparable<Course> {

    private String name;
    private String room;
    private String day;
    private String hour;

    // constructor and getters are omitted. you can add setters as well, but it's best that you keep this class immutable

    @Override
    public int compareTo(Course course) {
        // here you implement the logic of your comparison
    }
}

The benefit here is that, by implementing the Comparable<T> interface provided by the Java API, you specify that the instances of your Course class have a natural ordering. Then you can use Collections.sort() and your list of courses will be automatically sorted in the way you want. Then you can use it to back your table model and render it in the table.

Edit 1: A bit of a clarification on my suggestion:

Right now you read text data from a file, transform each row into an array of strings and pass it to a DefaultTableModel that supplies data to your JTable.

Instead of doing this, you can a bit more complexity to the code, but end up with a better solution from an architectural point of view. What are the steps:

  • Define a model class (like the example Course class) that will hold the data that is saved in your text file. Implement logic to transform each row of the file into an instance of the Course class. This instances will represent your data and you will use them to populate your table with data.
  • Implement your own TableModel that holds a sorted list of Course instances (those are the instances you read from the file). Use the implemented model to supply data to your JTable.

Upvotes: 0

camickr
camickr

Reputation: 324118

one of them are Days of the Weak(Monday-Friday)

So the data in the TableModel could be stored as an Integer to represent the day of the week. Then you use a custom renderer to convert the Integer value to a descriptive value.

Read the section from the Swing tutorial on Using Custom Renderers for an example.

In your case the code in the setValue(...) method would be something like:

int dayOfWeek = (Integer)value;

switch (dayOfWeek)
{
    case 1: setText("Monday"); break;
    case 2: setText("Tuesday"); break;
    case 3: ...
    default: value.toString();
}

the others are Hours(HH:mm),

In this case you are storing two pieces of information. So this means you need to parse the data into two times and then create a custom Comparator to sort based on the first time.

Another option might be to create two columns: "Start Time", "End Time". Then you could store Date objects in the TableModel and then just use the default Comparator that will sort by Date.

Upvotes: 1

Aziuth
Aziuth

Reputation: 3902

Simply implement it yourself. Use some basic sorting algorithm, like quick sort, bubble sort or merge sort (as found on wikipedia), and create your own comparison function to put the entries in order, like, in pseudo code:

 bool is_smaller(entry_1, entry_2){
   if (entry_1.weekday < entry_2.weekday) return true;
   if (entry_1.weekday > entry_2.weekday) return false;
   if (entry_1.course hour < entry_2.course_hour) return true;
   if (entry_1.course hour > entry_2.course_hour) return false;
   return false;
 }

(of course with another comparison function for weekday and course hour)

Upvotes: 0

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