code: @SuppressWarnings({"ResultOfMethodCallIgnored"})
      public static void visitFiles(final File pDirectory, final FileFilter pFilter, final Visitor<File> pVisitor) {
          Validate.notNull(pDirectory, "directory");
          Validate.notNull(pVisitor, "visitor");
  
          pDirectory.listFiles(new FileFilter() {
              public boolean accept(final File pFile) {
                  if (pFilter == null || pFilter.accept(pFile)) {
                      pVisitor.visit(pFile);
                  }
  
                  return false;
              }
          });
      }
docs: Visits all files in {@code pDirectory}. Optionally filtered through a {@link FileFilter}.
  
  @param pDirectory the directory to visit files in
  @param pFilter the filter, may be {@code null}, meaning all files will be visited
  @param pVisitor the visitor
  
  @throws IllegalArgumentException if either {@code pDirectory} or {@code pVisitor} are {@code null}
  
  @see com.twelvemonkeys.util.Visitor