RTI Connext Java API
Version 5.2.0
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Configures the availability of data. More...
Public Attributes | |
boolean | enable_required_subscriptions |
Enables support for required subscriptions in a com.rti.dds.publication.DataWriter. | |
final Duration_t | max_data_availability_waiting_time |
Defines how much time to wait before delivering a sample to the application without having received some of the previous samples. | |
final Duration_t | max_endpoint_availability_waiting_time |
Defines how much time to wait to discover DataWriters providing samples for the same data source (virtual GUID). | |
final EndpointGroupSeq | required_matched_endpoint_groups |
A sequence of endpoint groups. | |
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final QosPolicyId_t | id |
The ID of this QoS policy. | |
final String | policy_name |
The name of this QoS policy. | |
Additional Inherited Members | |
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abstract boolean | equals (Object obj) |
abstract int | hashCode () |
String | toString () |
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Struct () | |
abstract void | pull_from_nativeI (long native_status) |
abstract void | push_to_nativeI (long native_status) |
Configures the availability of data.
This QoS policy is used in the context of two features:
Collaborative DataWriters
The Collaborative DataWriters feature allows having multiple DataWriters publishing samples from a common logical data source. The DataReaders will combine the samples coming from the DataWriters in order to reconstruct the correct order at the source.
This QoS policy allows you to configure the ordering and combination process in the DataReader and can be used to support two different use cases:
Each sample published in a DDS domain for a given logical data source is uniquely identified by a pair (virtual GUID, virtual sequence number). Samples from the same data source (same virtual GUID) can be published by different DataWriters. A DataReader will deliver a sample (VGUIDn, VSNm) to the application if one of the following conditions is satisfied:
A DataWriter announces potential availability of samples by using virtual heartbeats (HBs).
When com.rti.dds.infrastructure.PresentationQosPolicy.access_scope is set to com.rti.dds.infrastructure.PresentationQosPolicyAccessScopeKind.PresentationQosPolicyAccessScopeKind.TOPIC_PRESENTATION_QOS or com.rti.dds.infrastructure.PresentationQosPolicyAccessScopeKind.PresentationQosPolicyAccessScopeKind.INSTANCE_PRESENTATION_QOS, the virtual HB contains information about the samples contained in the com.rti.dds.publication.DataWriter history.
When com.rti.dds.infrastructure.PresentationQosPolicy.access_scope is set to com.rti.dds.infrastructure.PresentationQosPolicyAccessScopeKind.PresentationQosPolicyAccessScopeKind.GROUP_PRESENTATION_QOS, the virtual HB contains information about all DataWriters in the com.rti.dds.publication.Publisher.
The frequency at which virtual HBs are sent is controlled by the protocol parameters com.rti.dds.infrastructure.RtpsReliableWriterProtocol_t.virtual_heartbeat_period and com.rti.dds.infrastructure.RtpsReliableWriterProtocol_t.samples_per_virtual_heartbeat.
Required Subscriptions
In the context of Required Subscriptions, this QoS policy can be used to configure a set of Required Subscriptions on a com.rti.dds.publication.DataWriter.
Required subscriptions are preconfigured, named subscriptions that may leave and subsequently rejoin the network from time to time, at the same or different physical locations. Any time a required subscription is disconnected, any samples that would have been delivered to it are stored for delivery if and when the subscription rejoins the network.
For a DataWriter, the setting of AVAILABILITY must be set consistenly with that of the RELIABILITY and DURABILITY.
If com.rti.dds.infrastructure.AvailabilityQosPolicy.enable_required_subscriptions is set to com.rti.dds.infrastructure.true, com.rti.dds.infrastructure.ReliabilityQosPolicy.kind must be set to com.rti.dds.infrastructure.ReliabilityQosPolicyKind.ReliabilityQosPolicyKind.RELIABLE_RELIABILITY_QOS and com.rti.dds.infrastructure.DurabilityQosPolicy must be set to a value different than com.rti.dds.infrastructure.DurabilityQosPolicyKind.DurabilityQosPolicyKind.VOLATILE_DURABILITY_QOS.
boolean enable_required_subscriptions |
Enables support for required subscriptions in a com.rti.dds.publication.DataWriter.
[default] com.rti.dds.infrastructure.false
final Duration_t max_data_availability_waiting_time |
Defines how much time to wait before delivering a sample to the application without having received some of the previous samples.
Collaborative DataWriters
A sample identified by (VGUIDn, VSNm) will be delivered to the application if this timeout expires for the sample and the following two conditions are satisfied:
Required Subscriptions
This field is not applicable to Required Subscriptions.
[default] com.rti.dds.infrastructure.Duration_t.AUTO (com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE for com.rti.dds.infrastructure.PresentationQosPolicyAccessScopeKind.PresentationQosPolicyAccessScopeKind.GROUP_PRESENTATION_QOS. Otherwise, 0 seconds)
[range] [0, com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE], com.rti.dds.infrastructure.Duration_t.AUTO
final Duration_t max_endpoint_availability_waiting_time |
Defines how much time to wait to discover DataWriters providing samples for the same data source (virtual GUID).
Collaborative DataWriters
The set of endpoint groups that are required to provide samples for a data source can be configured using required_matched_endpoint_groups.
A non-consecutive sample identified by (VGUIDn, VSNm) cannot be delivered to the application unless DataWriters for all the endpoint groups in required_matched_endpoint_groups are discovered or this timeout expires.
Required Subscriptions
This field is not applicable to Required Subscriptions.
[default] com.rti.dds.infrastructure.Duration_t.AUTO (com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE for com.rti.dds.infrastructure.PresentationQosPolicyAccessScopeKind.PresentationQosPolicyAccessScopeKind.GROUP_PRESENTATION_QOS. Otherwise, 0 seconds)
[range] [0, com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE], com.rti.dds.infrastructure.Duration_t.AUTO
final EndpointGroupSeq required_matched_endpoint_groups |
A sequence of endpoint groups.
Collaborative DataWriters
In the context of Collaborative DataWriters, it specifies the set of endpoint groups that are expected to provide samples for the same data source.
The quorum count in a group represents the number of DataWriters that must be discovered for that group before the DataReader is allowed to provide non consecutive samples to the application.
A DataWriter becomes a member of an endpoint group by configuring the role_name in com.rti.dds.publication.DataWriterQos.publication_name.
Required Subscriptions
In the context of Required Subscriptions, it specifies the set of Required Subscriptions on a com.rti.dds.publication.DataWriter.
Each Required Subscription is specified by a name and a quorum count.
The quorum count represents the number of DataReaders that have to acknowledge the sample before it can be considered fully acknowledged for that Required Subscription.
A DataReader is associated with a Required Subscription by configuring the role_name in com.rti.dds.subscription.DataReaderQos.subscription_name.
[default] Empty sequence