private static void beInteractive() throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String line;
		do {
			line = in.readLine();
			if (line.startsWith("pub"))
				publish(line.substring(4));
			if (line.startsWith("sub"))
				subscribe(line.substring(4));
			if (line.startsWith("unsub"))
				unsubscribe(line.substring(6));
			if (line.startsWith("topic")) {
				topic = line.substring(6);
			}
		} while(!"bye".equals(line));
		
	}