How to retrieve and set the huge String data retrieved -- to a JTextArea in swing?

I have 2 classes -A and B.I am building a GUI for retrieving a list of files. Class B is for recursion and returns a generic List of files. Class A is for GUI and retrieves the list of files and converts each file to a string.

Now, My problem is that when i call System.out.println(SomeFileName.toString()); in Class B. the Output is BLAZING fast ! But when i retrieve the same list of files via Class A and append the output to a JTextArea -- then the processing becomes a Million times slower.

Can anybody give me a solution ? Should i use buffers ? or I was looking over, somewhere it was suggested that i use a Document for a JTextArea ! I am using NetBeans.

Class A is coded like this :

     List<File> hoohoo = cr.catalog(partition);
        Iterator<File> it = hoohoo.iterator();
        while (it.hasNext()) {
            File myf = it.next();
            filesText.append(myf.toString() + NEWLINE);
        }

Class B looks like this ::

    public List<File> catalog(String file) {
    List<File> fileList = new LinkedList<File>();
    File myfile = new File(file);
    File[] fileNme = myfile.listFiles();
    for (File name : fileNme) {
        if (name.isDirectory()) {
            fileList.add(name);
            List<File> fist = sub_Catalogue(name);
            Iterator<File> it = fist.iterator();
            while (it.hasNext()) {
                fileList.add(it.next());
            }
        } else if (name.isFile()) {
            fileList.add(name);
        }
    }
    return fileList;
}

private List<File> sub_Catalogue(File name) {
    List<File> fileList2 = new LinkedList<File>();
    File[] names = name.listFiles();
    Humpty:
    if (names == null) {
        break Humpty;
    } else {
        HooHaa:
        for (File n : names) {
            if (n.isFile()) {
                fileList2.add(n);
     开发者_如何学Python       } else if (n.isDirectory()) {
                fileList2.add(n);
                List<File> fileList3 = sub_Catalogue(n);
                Iterator<File> uf = fileList3.iterator();
                while (uf.hasNext()) {
                    fileList2.add(uf.next());
                }
            }
        }
    }
    return fileList2;
}

The problem is likely to be that the JTextArea is doing lots of work on each setText/append call. Calling that method a million times will grow the internal string a little bit at a time and do some work. You probably end up with an O(N^2)-like complexity on the size of the list.

Try the following: using a StringBuilder, combine all the strings in the list to form just a single string. Then call setText on the JTextArea using this single big string.

A more efficient way to build the string that you will put as text to the JTextArea is to use a StringBuilder:

 List<File> hoohoo = cr.catalog(partition);
 Iterator<File> it = hoohoo.iterator();
 StringBuilder filesSB = new StringBuilder();
 while (it.hasNext()) {
     File myf = it.next();
     filesSB.append(myf.toString());
     filesSB.append("\n");
 }
 filesText.setText(filesSB.toString());

Here is an article on loading text efficiently in Swing:
http://users.cs.cf.ac.uk/O.F.Rana/jdc/swing-nov7-01.txt