Package org.apache.commons.io.filefilter

Class EmptyFileFilter

  • All Implemented Interfaces:
    FileFilter, FilenameFilter, Serializable, FileVisitor<Path>, PathFilter, PathVisitor, IOFileFilter
    public class EmptyFileFilter
extends AbstractFileFilter
implements Serializable
    This filter accepts files or directories that are empty.

    If the File is a directory it checks that it contains no files.

    Example, showing how to print out a list of the current directory's empty files/directories:

    Using Classic IO

     File dir = new File(".");
 String[] files = dir.list(EmptyFileFilter.EMPTY);
 for (String file : files) {
     System.out.println(file);
 }

    Example, showing how to print out a list of the current directory's non-empty files/directories: 

     File dir = new File(".");
 String[] files = dir.list(EmptyFileFilter.NOT_EMPTY);
 for (String file : files) {
     System.out.println(file);
 }

    Using NIO

     final Path dir = Paths.get("");
 final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(EmptyFileFilter.EMPTY);
 //
 // Walk one dir
 Files.walkFileTree(dir, Collections.emptySet(), 1, visitor);
 System.out.println(visitor.getPathCounters());
 System.out.println(visitor.getFileList());
 //
 visitor.getPathCounters().reset();
 //
 // Walk dir tree
 Files.walkFileTree(dir, visitor);
 System.out.println(visitor.getPathCounters());
 System.out.println(visitor.getDirList());
 System.out.println(visitor.getFileList());
    Since:
    1.3
    See Also:
    Serialized Form

    • Field Detail

      • EMPTY

        public static final IOFileFilter EMPTY
        Singleton instance of empty filter

      • NOT_EMPTY

        public static final IOFileFilter NOT_EMPTY
        Singleton instance of not-empty filter

    • Method Detail

      • accept

        public boolean accept​(File file)
        Checks to see if the file is empty.
        Specified by:
        accept in interface FileFilter
        Specified by:
        accept in interface IOFileFilter
        Overrides:
        accept in class AbstractFileFilter
        Parameters:
        file - the file or directory to check
        Returns:
        true if the file or directory is empty, otherwise false.

      • accept

        public FileVisitResult accept​(Path file,
                              BasicFileAttributes attributes)
        Checks to see if the file is empty.
        Specified by:
        accept in interface IOFileFilter
        Specified by:
        accept in interface PathFilter
        Parameters:
        file - the file or directory to check
        attributes - the file's basic attributes (TODO may be null).
        Returns:
        true if the file or directory is empty, otherwise false.
        Since:
        2.9.0