public static void copyDir( @NotNull File fromDir, @NotNull File toDir, @Nullable final FileFilter filter) throws IOException { ensureExists(toDir); if (isAncestor(fromDir, toDir, true)) { LOG.error(fromDir.getAbsolutePath() + " is ancestor of " + toDir + ". Can't copy to itself."); return; } File[] files = fromDir.listFiles(); if (files == null) throw new IOException( CommonBundle.message("exception.directory.is.invalid", fromDir.getPath())); if (!fromDir.canRead()) throw new IOException( CommonBundle.message("exception.directory.is.not.readable", fromDir.getPath())); for (File file : files) { if (filter != null && !filter.accept(file)) { continue; } if (file.isDirectory()) { copyDir(file, new File(toDir, file.getName()), filter); } else { copy(file, new File(toDir, file.getName())); } } }