this.supportedProtocols = new HashSet<String>(Arrays.asList(new String[]{"http","https","ftp","smb","file"}));
// initiate loader objects
this.log = new Log("LOADER");
this.httpLoader = new HTTPLoader(sb, this.log);
this.ftpLoader = new FTPLoader(sb, this.log);
this.smbLoader = new SMBLoader(sb, this.log);
this.fileLoader = new FileLoader(sb, this.log);
this.loaderSteering = new ConcurrentHashMap<DigestURI, Semaphore>();
}