public boolean cacheIsExpired() {
        lock.readLock().lock();
        try {
            return System.currentTimeMillis() - file.lastModified() > cacheTime;
        } finally {
            lock.readLock().unlock();
        }
    }
check whether cache is expired.
@return true if cache is expired else false.
inlong-agent/agent-common/src/main/java/org/apache/inlong/agent/cache/LocalFileCache.java