public boolean isUser() {
        return getModel().getEntityType() == EntityType.USER;
    }
Returns whether the underlying entity is a user. Entities may be either
users or user groups.

@return
    true if the underlying entity is a user, false otherwise.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/base/ModeledPermissions.java