GroupDataQosPolicy Class Reference
[GROUP_DATA]

Attaches a buffer of opaque data that is distributed by means of Built-in Topics during discovery. More...

Inheritance diagram for GroupDataQosPolicy:

List of all members.

Public Attributes
final ByteSeq	value
	a sequence of octets

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Detailed Description

Attaches a buffer of opaque data that is distributed by means of Built-in Topics during discovery.

Entity:

com.rti.dds.publication.Publisher, com.rti.dds.subscription.Subscriber

Properties:

RxO = NO
Changeable = YES

See also:

com.rti.dds.domain.DomainParticipant.get_builtin_subscriber

Usage

The additional information is attached to a com.rti.dds.publication.Publisher or com.rti.dds.subscription.Subscriber. This extra data is not used by RTI Connext itself. When a remote application discovers the com.rti.dds.publication.Publisher or com.rti.dds.subscription.Subscriber, it can access that information and use it for its own purposes.

Use cases for this QoS policy, as well as the com.rti.dds.infrastructure.TopicDataQosPolicy and com.rti.dds.infrastructure.UserDataQosPolicy, are often application-to-application identification, authentication, authorization, and encryption purposes. For example, applications can use Group or User Data to send security certificates to each other for RSA-type security.

In combination with com.rti.dds.subscription.DataReaderListener, com.rti.dds.publication.DataWriterListener and operations such as com.rti.dds.domain.DomainParticipant.ignore_publication and com.rti.dds.domain.DomainParticipant.ignore_subscription, this QoS policy can help an application to define and enforce its own security policies. For example, an application can implement matching policies similar to those of the com.rti.dds.infrastructure.PartitionQosPolicy, except the decision can be made based on an application-defined policy.

The use of this QoS is not limited to security; it offers a simple, yet flexible extensibility mechanism.

Important: RTI Connext stores the data placed in this policy in pre-allocated pools. It is therefore necessary to configure RTI Connext with the maximum size of the data that will be stored in policies of this type. This size is configured with com.rti.dds.infrastructure.DomainParticipantResourceLimitsQosPolicy.publisher_group_data_max_length and com.rti.dds.infrastructure.DomainParticipantResourceLimitsQosPolicy.subscriber_group_data_max_length.

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Member Data Documentation

final ByteSeq value

a sequence of octets

[default] Empty (zero-sized)

[range] Octet sequence of length [0,max_length]