LifespanQosPolicy Class Reference

Specifies how long the data written by the com.rti.dds.publication.DataWriter is considered valid. More...

Inheritance diagram for LifespanQosPolicy:

Public Attributes
final Duration_t	duration
	Maximum duration for the data's validity.
Public Attributes inherited from QosPolicy
final QosPolicyId_t	id
	The ID of this QoS policy.
final String	policy_name
	The name of this QoS policy.

Additional Inherited Members
Public Member Functions inherited from Struct
abstract boolean	equals (Object obj)
abstract int	hashCode ()
String	toString ()
Protected Member Functions inherited from Struct
	Struct ()
abstract void	pull_from_nativeI (long native_status)
abstract void	push_to_nativeI (long native_status)

Detailed Description

Specifies how long the data written by the com.rti.dds.publication.DataWriter is considered valid.

Each data sample written by the com.rti.dds.publication.DataWriter has an associated expiration time beyond which the data should not be delivered to any application. Once the sample expires, the data will be removed from the com.rti.dds.subscription.DataReader caches as well as from the transient and persistent information caches.

The expiration time of each sample from the com.rti.dds.publication.DataWriter's cache is computed by adding the duration specified by this QoS policy to the sample's source timestamp. The expiration time of each sample from the com.rti.dds.subscription.DataReader's cache is computed by adding the duration to the reception timestamp.

See Also

com.rti.ndds.example.FooDataWriter.write

com.rti.ndds.example.FooDataWriter.write_w_timestamp

Entity:

com.rti.dds.topic.Topic, com.rti.dds.publication.DataWriter

Properties:

RxO = N/A
Changeable = YES

Usage

The Lifespan QoS policy can be used to control how much data is stored by RTI Connext. Even if it is configured to store "all" of the data sent or received for a topic (see com.rti.dds.infrastructure.HistoryQosPolicy), the total amount of data it stores may be limited by this QoS policy.

You may also use this QoS policy to ensure that applications do not receive or act on data, commands or messages that are too old and have 'expired.'

To avoid inconsistencies, multiple writers of the same instance should have the same lifespan.

See Also

com.rti.dds.subscription.SampleInfo.source_timestamp

com.rti.dds.subscription.SampleInfo.reception_timestamp

Member Data Documentation

final Duration_t duration

Maximum duration for the data's validity.

[default] com.rti.dds.infrastructure.Duration_t.INFINITE

[range] [1 nanosec, 1 year] or com.rti.dds.infrastructure.Duration_t.INFINITE