Delete from LinkedList of Files with occurrences from an Array of allowed extensions?

Question

I have a LinkedList of files which I populated using the following line:

File file = new File(directoryPath);
List<File> filesList = new LinkedList<File>(Arrays.asList(file.listFiles()));

This gets me all the files in given directoryPath string.

I then have an Array of the file extensions that are allowed and would like to delete any file (not directory) that's inside which doesn't match up.

String[] file_ext = new String[] {"ext1", "ext2", "ext3"};

How can I proceed to implement this?

What do you want to end up with? If one of the files is a directory do you want to search that too? — Boris the Spider, Aug 04 '13 at 13:02

Akash · Accepted Answer · 2013-08-04T13:45:52.560

1

You can use something like this

final String[]  file_ext = new String[] {"ext1", "ext2", "ext3"};

FilenameFilter filter = new FilenameFilter() {

    @Override
    public boolean accept(File dir, String name) {
            for(int i=file_ext.length-1;i>=0;i--)
                if( name.endsWith( "." + file_ext[i]) )
                    return true;
            return false;
        }
    };

File file = new File(directoryPath);
List<File> filesList = new LinkedList<File>(Arrays.asList(file.listFiles(filter)));

Updated: As per 'Borsi the Spider' comment, to avoid false matches such as files.notext1, the searching matches the . character as well

edited Aug 04 '13 at 13:45

answered Aug 04 '13 at 13:01

Akash

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@BoristheSpider I have modified to consider the searching including the `.` character – Akash Aug 04 '13 at 13:11
This is ultimately what I ended up with but without using a FilenameFilter. Thanks. – Linkandzelda Aug 04 '13 at 17:49

score 0 · Answer 2 · answered Aug 04 '13 at 12:50

0

Take list of files and check if they names ends with any ext from file_ext, if yes, add them to list of filesToDelete
Delete files from filesToDelete list.

answered Aug 04 '13 at 12:50

MGorgon

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Since this was the first answer I went with it, thanks everyone else for your answers too. – Linkandzelda Aug 04 '13 at 17:45

score 0 · Answer 3 · edited May 23 '17 at 12:05

0

Use a FilenameFilter, an example can be found here

edited May 23 '17 at 12:05

Community

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answered Aug 04 '13 at 12:52

earcam

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Boris the Spider · Answer 4 · 2013-08-04T13:12:20.870

Use a FileNameExtensionFilter

final FileNameExtensionFilter fnef = new FileNameExtensionFilter("", "ext1", "ext2", "ext3");
final List<File> files = new LinkedList<>();
for(final File f : new File(directoryPath).listFiles()) {
    if(fnef.accept(f)) files.add(f);
}

This is from Swing but it does exactly what you want and it doesn't have any dependencies on the EDT or anything odd.

You could even wrap the FileNameExtensionFilter in a FileFilter façade and make it a one-liner:

final List<File> filesList = new LinkedList<>(Arrays.asList(new File(directoryPath).listFiles(new FileFilter() {
    final FileNameExtensionFilter fnef = new FileNameExtensionFilter("", "ext1", "ext2", "ext3");

    @Override
    public boolean accept(File pathname) {
        return fnef.accept(pathname);
    }
})));

Delete from LinkedList of Files with occurrences from an Array of allowed extensions?

4 Answers4