public String getIdentifier() throws GuacamoleException {
        return getRequiredParameter(IDENTIFIER_PARAMETER);
    }
Returns the identifier of the destination of the tunnel being requested.
As there are multiple types of destination objects available, and within
multiple data sources, the associated object type and data source are
also necessary to determine what this identifier refers to.

@return
    The identifier of the destination of the tunnel being requested.

@throws GuacamoleException
    If the identifier was not present in the request.
guacamole/src/main/java/org/apache/guacamole/tunnel/TunnelRequest.java