@Override
                    public boolean accept(File file, String string) {
                        return string.endsWith(".json");
                    }
Reads through all pre-defined protocols and any protocols within the
"protocols" subdirectory of GUACAMOLE_HOME, returning a map containing
each of these protocols. The key of each entry will be the name of that
protocol, as would be passed to guacd during connection.

@return
    A map of all available protocols.
guacamole-ext/src/main/java/org/apache/guacamole/environment/LocalEnvironment.java