public Authorization getAuthorization(String username) {
        return authorizations.get(username);
    }
Returns the authorization corresponding to the user having the given
username, if any.

@param username The username to find the authorization for.
@return The authorization corresponding to the user having the given
        username, or null if no such authorization exists.
guacamole/src/main/java/org/apache/guacamole/auth/file/UserMapping.java