.. _dds_layers_domain_participant_factory:

DomainParticipantFactory
========================

The sole purpose of this class is to allow the creation and destruction of :ref:`dds_layers_domain_participant` objects.

DomainParticipantFactory does not accept any Listener, since it is not an Entity.

.. note::

   In Safe DDS, ``DomainParticipantFactory`` shall be instantiated by the application and it is not a singleton.

.. note::

   In Safe DDS, the default ``DomainParticipantFactory`` constructor will use :ref:`default transport <architecture_transport_default_transport>` and :ref:`default platform <architecture_platform_default_platform>` implementations for creating :ref:`dds_layers_domain_participant` instances.

   For a custom transport, the specific constructor can be used:

   .. literalinclude:: ../../../code/architecture_reference/main.cpp
      :language: c++
      :start-after: // HANDLING_DEFAULT_DOMAINPARTICIPANT_TRANSPORT
      :end-before: //! HANDLING_DEFAULT_DOMAINPARTICIPANT_TRANSPORT
      :dedent: 8

.. _dds_layers_domain_participant_factory_qos:

DomainParticipantFactoryQos
---------------------------

``DomainParticipantFactoryQos`` controls the behavior of the :ref:`dds_layers_domain_participant_factory`.
Internally it does not contain any members.

.. note::

   In Safe DDS, it is important to note that the ``DomainParticipantFactoryQos`` does not possess a :ref:`entityfactoryqospolicy`.
   This is a direct consequence of the fact that a Safe DDS :ref:`dds_layers_domain_participant_factory` consistently creates :ref:`dds_layers_domain_participant` instances in a not enabled state.

   The underlying reason for this design choice is that the Safe DDS :ref:`dds_layers_domain_participant` becomes incapable of creating subentities once it transitions into an enabled state.
   This ensures that the usage of Safe DDS remains secure and adheres to the established guidelines.

.. only :: SafetyManual

   .. _dds_layers_safe_domain_participant_factory:

   SafeDomainParticipantFactory
   ============================

   .. include:: ../../../safety_manual/rules/RULE_SAFEDOMAINPARTICIPANTFACTORY.inc
   .. include:: ../../../safety_manual/rules/RULE_CREATION_ORDER.inc

   :class:`SafeDomainParticipantFactory` is the safe counterpart of the DDS DomainParticipantFactory, and its usage is mandatory under safety conditions.
   Its purpose is, in addition to that of the :ref:`dds_layers_domain_participant_factory`, to:

   #. Perform extra safety checks on DomainParticipant enabling.
   #. Act as Safe DDS :ref:`Platform <architecture_platform>` so that it can control the library's memory allocation.

   For more information about how to use the ``SafeDomainParticipantFactory`` to create participants, please refer to :ref:`dds_layers_create_safe_domain_participant_listeners` and :ref:`dds_layers_create_safe_domain_participant_status`.