Joining two File[] arrays

[mandlar suurla]

How to make it i am losing my mind. Cant be done like this


file = oneArray + otherArray;

[Jelle Klap]

What exactly are you trying to accomplish?
If you simply want to merge two arrays, not caring about duplicates, I think making use of System.arraycopy() will probably yield the best performance.

[mandlar suurla]

k the actual problem is making FileSystemTableModel so it would display the system in table. The file list i get with File class. And two arrays are because i want the folders listed first and files after folders.

[Rob Spoor]

There is another way of solving this: just list them all (listFiles), then use Arrays.sort to sort them. You will need a Comparator for that:

public class FileComparator implements Comparator<File>
{
    public int compare(File f1, File f2)
    {
        boolean dir1 = f1.isDirectory();
        boolean dir2 = f2.isDirectory();
        if (dir1 == dir2)
        {
            return f1.compareTo(f2);
        }
        // either f1 is a directory or f2, but not both
        return (dir1 ? -1 : 1);
    }
}

This will also help you with the sorting of your files. You cannot assume that listFiles will return your files in alphabetical order; some operating systems use creation date sorting.

Of course this method is O(n log n) against the O(n) of listing the files twice, then merging, but unless there are a lot of files / folders in each folder you won't notice the difference.


By the way, that code came out of my own FileTreeModel, so it has proven itself already in existing code
[ June 11, 2008: Message edited by: Rob Prime ]