CODEWITHSUNDEEP
audiojava
kumuda
kumuda

Reputation: 509

how to extract only audio files and put them in an arrayList

I am writing a program where i want all my audio files (.mp3,.wav etc ) files in an arrayList my code looks like this:

public class FileTest
{

    public ArrayList<File> list(String directoryName, ArrayList<File> files)
    {
        File directory = new File(directoryName);
        File[] fList = directory.listFiles();
        for (File file : fList) {
            if (file.isFile() **&& (if the file is an audio file)**) {
                files.add(file);
            } else if (file.isDirectory()) {
                list(file.getAbsolutePath(), files);
            }

        }

        return files;
    }

    public static void main(String[] args)
    {
        FileTest fileTest = new FileTest();

        ArrayList<File> files = new ArrayList<File>();

        files = fileTest.list("/media/kumuda/D804C38204C361DC/Program Files",files);

        for(File file : files)
        {
            System.out.println(file.getAbsolutePath());
        }
    }
}

I want to check if the file is an audio file before adding it to my arraylist. I searched for api's and came across Apache Tika library. but i am not getting how it exactly works. Please can anyone help me ?

Upvotes: 1

Views: 1296

Answers (2)

fge
fge

Reputation: 121750

Here is how you would do that using Files.

First, create a FileVisitor. Extend SimpleFileVisitor since it is enough for your needs:

public final class AudioFileCollector
    extends SimpleFileVisitor<Path>
{
    private final List<Path> fileList;

    public AudioFileCollector(final List<Path> fileList)
    {
        this.fileList = fileList;
    }

    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
        throws IOException
    {
        // We know this is a regular file here, so now we just need to check the type
        switch (Files.probeContentType(file)) {
            case "audio/x-wav": // wav file
            case "audio/mpeg":  // mp3
                fileList.add(file);
            default:
        }
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult postVisitDirectory(Path dir, IOException e)
        throws IOException
    {
        if (e != null)
            throw e;
        return FileVisitResult.CONTINUE;
    }

Then walk your directory with this visitor:

final Path baseDir = Paths.get("...");
final List<Path> fileList = new ArrayList<>();
final FileVisitor<Path> collector = new AudioFileCollector(fileList);

Files.walkFileTree(baseDir, collector);

Done!

Note the use of Files.probeContentType().

Solution with Java 8 (I guess it could be better):

public final class Main
{
    public static void main(final String... args)
        throws IOException
    {
        final List<String> extensions = Arrays.asList(".mp3", ".wav");
        final Path start = Paths.get("...");

        Files.walk(start).map(Object::toString)
            .filter(s -> extensions.stream().anyMatch(s::endsWith))
            .forEach(System.out::println);
    }

}

If you want to collect in a list, replace .forEach() with .collect(Collectors.toList()).

Upvotes: 2

Alexandru Severin
Alexandru Severin

Reputation: 6228

The easiest way would be to use ragex and check if the filename matches a pattern. (http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html)

Something like 

if( Pattern.matches("[a-zA-Z0-9]+.mp3",file) || Pattern.matches("[a-zA-Z0-9]+.wav",file) )     
{
// your code here
}

Upvotes: 0

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