private void touchInBackground(File file) throws IOException {
        Files.setLastModifiedNow(file);
        List<File> files = Files.getLruListFiles(file.getParentFile());
        trim(files);
    }
{@link DiskUsage} that uses LRU (Least Recently Used) strategy to trim cache.
VideoCache/src/main/java/com/yc/videocache/file/LruDiskUsage.java