JTree - file system viewer tree only with fixed file extensions

Question

I'm in the process of writing a school project and I have one problem i can't solve. I have a tree that shows directories and file paths but I need to display only .mp3 and .wav files. Can someone give me some advice how to do that? I have a class with a tree model:

public boolean isLeaf(Object node) {
    File file = (File) node;
    return file.isFile();
}

public int getIndexOfChild(Object parent, Object child) {
    File directory = (File) parent;
    File file = (File) child;
    String[] children = directory.list();
    for (int i = 0; i < children.length; i++) {
        if (file.getName().equals(children[i])) {
            return i;
        }
    }
    return -1;

}

public void valueForPathChanged(TreePath path, Object value) {
    File oldFile = (File) path.getLastPathComponent();
    String fileParentPath = oldFile.getParent();
    String newFileName = (String) value;
    File targetFile = new File(fileParentPath, newFileName);
    oldFile.renameTo(targetFile);
    File parent = new File(fileParentPath);
    int[] changedChildrenIndices = { getIndexOfChild(parent, targetFile) };
    Object[] changedChildren = { targetFile };
    fireTreeNodesChanged(path.getParentPath(), changedChildrenIndices, changedChildren);

}

private void fireTreeNodesChanged(TreePath parentPath, int[] indices, Object[] children) {
    TreeModelEvent event = new TreeModelEvent(this, parentPath, indices, children);
    Iterator iterator = listeners.iterator();
    TreeModelListener listener = null;
    while (iterator.hasNext()) {
        listener = (TreeModelListener) iterator.next();
        listener.treeNodesChanged(event);
    }
}

public void addTreeModelListener(TreeModelListener listener) {
    listeners.add(listener);
}

public void removeTreeModelListener(TreeModelListener listener) {
    listeners.remove(listener);
}

private class TreeFile extends File {
    public TreeFile(File parent, String child) {
        super(parent, child);
    }

    public String toString() {
        return getName();
    }
}

String getFileDetails(File file) {
    if (file == null)
        return "";
    StringBuffer buffer = new StringBuffer();
    buffer.append("Name: " + file.getName() + "\n");
    buffer.append("Path: " + file.getPath() + "\n");
    buffer.append("Size: " + (double) (file.length() / 1024) / 1024 + " MB" + "\n");
    return buffer.toString();
}

Answer 1

String[] children = directory.list();

Wherever you are listing the children, like in the above, know that File.list() can also take a FilenameFilter. There is also a similar method called File.listFiles() which can take a FileFilter (very similar). Using one of these, you can filter your files by filename (which includes the extension).