How to display file names in ascending order using JTree in GUI?

Question

I have a set of files in a folder, and all of them starting with a similar name pattern. Here is an example:

Spectrum_1.txt
Spectrum_2.txt
Spectrum_3.txt
....
....
....
Spectrum_10.txt
Spectrum_11.txt
....
....
....
Spectrum_20.txt
....
....
....

I am able to list all the files from the specified folder, but the list is not in an ascending order of the spectrum number. I have a sort method which could correct this:

public class SortFile {

    /**
     * Method which takes list of files as a fileArray and sorts them 
     * 
     * @param File[] files
     * @return File[] files
     */ 

    public File[] sortByNumber(File[] files) {

        Arrays.sort(files, new Comparator<File>() {
            //@Override
            public int compare(File o1, File o2) {
                int n1 = extractNumber(o1.getName());
                int n2 = extractNumber(o2.getName());
                return n1 - n2;
            }

            private int extractNumber(String name) {
                int i = 0;
                try {
                    int s = name.indexOf('_')+1;
                    int e = name.lastIndexOf('.');
                    String number = name.substring(s, e);
                    i = Integer.parseInt(number);
                } catch(Exception e) {
                    i = 0; // if filename does not match the format
                    // then default to 0
                }
                return i;
            }
        });

        return files;

    }
}

But, I am not sure how to get it working with the JTree code:

public void actionPerformed(ActionEvent e) {

        //Handle open button action.
        if (e.getSource() == OpenFileButton) {
            int returnVal = fc.showOpenDialog(GUIMain.this);

            if (returnVal == JFileChooser.APPROVE_OPTION) {
                file = fc.getSelectedFile();
                File[] filesInDirectory = file.listFiles();

                SortFile sf = new SortFile();

                // Calls sortByNumber method in class SortFile to list the files number wise
                filesInDirectory = sf.sortByNumber(filesInDirectory);

// Jtree takes the File datatype as input
       tree = new JTree(addNodes(null, file));

                // Add a listener
                tree.addTreeSelectionListener(new TreeSelectionListener() {
                    public void valueChanged(TreeSelectionEvent e) {
                        DefaultMutableTreeNode node = (DefaultMutableTreeNode) e
                                .getPath().getLastPathComponent();
                        System.out.println("You selected " + node);
                    }
                });

                spectralFilesScrollPane = new JScrollPane();
                spectralFilesScrollPane.getViewport().add(tree);
                spectralFilesScrollPane.setPreferredSize(new Dimension(290, 465));
                content.add(spectralFilesScrollPane);
//               // content.invalidate();
                content.validate();
                content.repaint();

            }
        }
    }

The problem I am facing is, the sort method returns an array of files and the JTree is using the File datatype. How can I resolve this?

Answer 1

Solved the problem by making changes into the addNodes method.