@Override
    public void remove(String identifier) throws GuacamoleException {
        throw new GuacamoleSecurityException("Permission denied.");
    }
Returns the Map which currently backs this SimpleDirectory. Changes to
this Map will affect future function calls that retrieve objects from
this SimpleDirectory.

@return
    The Map of objects which currently backs this SimpleDirectory.
guacamole-ext/src/main/java/org/apache/guacamole/net/auth/simple/SimpleDirectory.java