Configures the ability of a DDS::DataWriter to publish samples in response to a DDS::TopicQuery. More...

#include <managed_infrastructure.h>

Static Public Member Functions
static System::String ^	get_topicquerydispatch_qos_policy_name ()
	Stringified human-readable name for DDS::TopicQueryDispatchQosPolicy. More...

Public Attributes
Duration_t	publication_period
	Sets the periodic interval at which samples are published. More...

System::Int32	samples_per_period
	Sets the maximum number of samples to publish in each publication_period. More...

Properties
System::Boolean	enable `[get, set]`
	Allows this writer to dispatch TopicQueries. More...

Detailed Description

Configures the ability of a DDS::DataWriter to publish samples in response to a DDS::TopicQuery.

Enables the ability of a DDS::DataWriter to publish historical samples upon reception of a DDS::TopicQuery and how often they are published.

Since a TopicQuery selects previously written samples, the DataWriter must have a DDS::DurabilityQosPolicy::kind different from DDS::DurabilityQosPolicyKind::VOLATILE_DURABILITY_QOS. Also, DDS::ReliabilityQosPolicy::kind must be set to DDS::ReliabilityQosPolicyKind::RELIABLE_RELIABILITY_QOS.

A TopicQuery may select multiple samples at once. The writer will publish them periodically, independently from newly written samples. DDS::TopicQueryDispatchQosPolicy::publication_period configures the frequency of that period and DDS::TopicQueryDispatchQosPolicy::samples_per_period configures the maximum number of samples to publish each period.

If the DataWriter blocks during the publication of one of these samples, it will stop and try again the next period. (See DDS::TypedDataWriter::write for the conditions that may cause the write operation to block.)

All the DataWriters that belong to a single DDS::Publisher and enable TopicQueries share the same event thread, but each DataWriter schedules separate events. To configure that thread, see DDS::AsynchronousPublisherQosPolicy::topic_query_publication_thread.

If the DataWriter is dispatching more than one TopicQuery at the same time, the configuration of this periodic event applies to all of them. For example, if a DataWriter receives two TopicQueries around the same time, the period is 1 second, the number of samples per period is 10, the first TopicQuery selects 5 samples, and the second one selects 8, the DataWriter will immediately attempt to publish all 5 for the first TopicQuery and 5 for the second one. After one second, it will publish the remaining 3 samples.

Entity:: DDS::DataWriter

Properties:: RxO = N/A
Changeable = NO

See also: DDS::Publisher

Member Data Documentation

◆ publication_period

Duration_t DDS::TopicQueryDispatchQosPolicy::publication_period

Sets the periodic interval at which samples are published.

[default] 1 second

[range] [0,1 year]

◆ samples_per_period

System::Int32 DDS::TopicQueryDispatchQosPolicy::samples_per_period

Sets the maximum number of samples to publish in each publication_period.

[default] DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED

[range] [1, 100000000] or DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED

Property Documentation

◆ enable

System:: Boolean DDS::TopicQueryDispatchQosPolicy::enable

getset

Allows this writer to dispatch TopicQueries.

When set to true, this writer can receive and dispatch TopicQueries.

[default] false

Static Public Member Functions