2.5. EntityId

When monitoring a domain (see Initialize a monitor), Fast DDS Statistics Backend labels all the different discovered entities with an EntityId identifier that is unique in the context of the StatisticsBackend instance. This EntityId is used by the application, among other things, to query statistical data to the backend (see Get statistical data). To ease the use of the Fast DDS Statistics Backend API, EntityId exposes certain commonly used operations:

2.5.1. EntityId wildcard

EntityId allows for retrieving an ID that represents all the EntityIds:

EntityId all = EntityId::all();

2.5.2. Invalid EntityId

EntityId allows for retrieving an invalid ID:

EntityId invalid = EntityId::invalid();

2.5.3. Invalidate an EntityId

It is also possible to invalidate an EntityId:

EntityId entity_id;
entity_id.invalidate();

2.5.4. Check validity of an EntityId

It can be checked whether an EntityId is valid:

EntityId entity_id;
bool check = entity_id.is_valid();

2.5.5. Check EntityId represents all Entities

It can be checked whether an EntityId represents all the EntityIds:

EntityId entity_id;
bool check = entity_id.is_all();

2.5.6. Check validity and uniqueness of an EntityId

It can be checked whether an EntityId is valid and unique:

EntityId entity_id;
bool check = entity_id.is_valid_and_unique();

2.5.7. Comparison operations

EntityIds can be compared between them:

EntityId entity_id_1;
EntityId entity_id_2;
bool check = entity_id_1 < entity_id_2;
check = entity_id_1 <= entity_id_2;
check = entity_id_1 > entity_id_2;
check = entity_id_1 >= entity_id_2;
check = entity_id_1 == entity_id_2;
check = entity_id_1 != entity_id_2;

2.5.8. Output to OStream

EntityIds can be output to std::ostream:

EntityId entity_id;
std::cout << "EntityId: " << entity_id << std::endl;