private int getClientsCount() {
        synchronized (clientsLock) {
            int count = 0;
            for (HttpProxyCacheServerClients clients : clientsMap.values()) {
                count += clients.getClientsCount();
            }
            return count;
        }
    }
Checks is cache contains fully cached file for particular url.

@param url an url cache file will be checked for.
@return {@code true} if cache contains fully cached file for passed in parameters url.
VideoCache/src/main/java/com/yc/videocache/HttpProxyCacheServer.java