Package Summary Overview Summary

### class:FileVisitor [NONE]
- All Known Implementing Classes: SimpleFileVisitor
      public interface FileVisitor<T>
  A visitor of files. An implementation of this interface is provided to the `Files.walkFileTree` methods to visit each file in a file tree. Usage Examples: Suppose we want to delete a file tree. In that case, each directory should be deleted after the entries in the directory are deleted.
           Path start = ...
           Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
               @Override
               public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
                   throws IOException
               {
                   Files.delete(file);
                   return FileVisitResult.CONTINUE;
               }
               @Override
               public FileVisitResult postVisitDirectory(Path dir, IOException e)
                   throws IOException
               {
                   if (e == null) {
                       Files.delete(dir);
                       return FileVisitResult.CONTINUE;
                   } else {
                       // directory iteration failed
                       throw e;
                   }
               }
           });
  Furthermore, suppose we want to copy a file tree to a target location. In that case, symbolic links should be followed and the target directory should be created before the entries in the directory are copied.
           final Path source = ...
           final Path target = ...

           Files.walkFileTree(source, EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE,
               new SimpleFileVisitor<Path>() {
                   @Override
                   public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
                       throws IOException
                   {
                       Path targetdir = target.resolve(source.relativize(dir));
                       try {
                           Files.copy(dir, targetdir);
                       } catch (FileAlreadyExistsException e) {
                            if (!Files.isDirectory(targetdir))
                                throw e;
                       }
                       return CONTINUE;
                   }
                   @Override
                   public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
                       throws IOException
                   {
                       Files.copy(file, target.resolve(source.relativize(file)));
                       return CONTINUE;
                   }
               });
Since: 1.7

### method:preVisitDirectory(T, java.nio.file.attribute.BasicFileAttributes) [NONE]
- #### preVisitDirectory
      FileVisitResult preVisitDirectory(T dir,
                                        BasicFileAttributes attrs)
                                 throws IOException
Invoked for a directory before entries in the directory are visited. If this method returns `CONTINUE`, then entries in the directory are visited. If this method returns `SKIP_SUBTREE` or `SKIP_SIBLINGS` then entries in the directory (and any descendants) will not be visited. Parameters: `dir` - a reference to the directory `attrs` - the directory's basic attributes Returns: the visit result Throws: `IOException` - if an I/O error occurs

### method:visitFile(T, java.nio.file.attribute.BasicFileAttributes) [NONE]
- #### visitFile
      FileVisitResult visitFile(T file,
                                BasicFileAttributes attrs)
                         throws IOException
Invoked for a file in a directory. Parameters: `file` - a reference to the file `attrs` - the file's basic attributes Returns: the visit result Throws: `IOException` - if an I/O error occurs

### method:visitFileFailed(T, java.io.IOException) [NONE]
- #### visitFileFailed
      FileVisitResult visitFileFailed(T file,
                                      IOException exc)
                               throws IOException
Invoked for a file that could not be visited. This method is invoked if the file's attributes could not be read, the file is a directory that could not be opened, and other reasons. Parameters: `file` - a reference to the file `exc` - the I/O exception that prevented the file from being visited Returns: the visit result Throws: `IOException` - if an I/O error occurs

### method:postVisitDirectory(T, java.io.IOException) [NONE]
- #### postVisitDirectory
      FileVisitResult postVisitDirectory(T dir,
                                         IOException exc)
                                  throws IOException
Invoked for a directory after entries in the directory, and all of their descendants, have been visited. This method is also invoked when iteration of the directory completes prematurely (by a `visitFile` method returning `SKIP_SIBLINGS`, or an I/O error when iterating over the directory). Parameters: `dir` - a reference to the directory `exc` - `null` if the iteration of the directory completes without an error; otherwise the I/O exception that caused the iteration of the directory to complete prematurely Returns: the visit result Throws: `IOException` - if an I/O error occurs