RTI Connext Java API
Version 5.0.0
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Controls how a DataReader manages the lifecycle of the data that it has received. More...
Public Attributes | |
final Duration_t | autopurge_nowriter_samples_delay |
Maximum duration for which the com.rti.dds.subscription.DataReader will maintain information regarding an instance once its instance_state becomes com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE. | |
final Duration_t | autopurge_disposed_samples_delay |
Maximum duration for which the com.rti.dds.subscription.DataReader will maintain samples for an instance once its instance_state becomes com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE. | |
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) |
Controls how a DataReader manages the lifecycle of the data that it has received.
When a DataReader receives data, it is stored in a receive queue for the DataReader. The user application may either take the data from the queue or leave it there.
This QoS policy controls whether or not RTI Connext will automatically remove data from the receive queue (so that user applications cannot access it afterwards) when it detects that there are no more DataWriters alive for that data. It specifies how long a com.rti.dds.subscription.DataReader must retain information regarding instances that have the instance_state com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE.
Note: This policy is not concerned with keeping reliable reader state or discovery information.
The com.rti.dds.subscription.DataReader internally maintains the samples that have not been "taken" by the application, subject to the constraints imposed by other QoS policies such as com.rti.dds.infrastructure.HistoryQosPolicy and com.rti.dds.infrastructure.ResourceLimitsQosPolicy.
The com.rti.dds.subscription.DataReader also maintains information regarding the identity, view_state
and instance_state
of data instances even after all samples have been taken. This is needed to properly compute the states when future samples arrive.
Under normal circumstances the com.rti.dds.subscription.DataReader can only reclaim all resources for instances for which there are no writers and for which all samples have been 'taken'. The last sample the com.rti.dds.subscription.DataReader will have taken for that instance will have an instance_state
of either com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE or com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE depending on whether or not the last writer that had ownership of the instance disposed it.
In the absence of READER_DATA_LIFECYCLE, this behavior could cause problems if the application forgets to take those samples. "Untaken" samples will prevent the com.rti.dds.subscription.DataReader from reclaiming the resources and they would remain in the com.rti.dds.subscription.DataReader indefinitely.
For keyed Topics, the consideration of removing data samples from the receive queue is done on a per instance (key) basis. Thus when RTI Connext detects that there are no longer DataWriters alive for a certain key value of a Topic (an instance of the Topic), it can be configured to remove all data samples for that instance (key).
final Duration_t autopurge_nowriter_samples_delay |
Maximum duration for which the com.rti.dds.subscription.DataReader will maintain information regarding an instance once its instance_state
becomes com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE.
After this time elapses, the com.rti.dds.subscription.DataReader will purge all internal information regarding the instance, any "untaken" samples will also be lost.
[default] com.rti.dds.infrastructure.Duration_t.INFINITE
[range] [1 nanosec, 1 year] or com.rti.dds.infrastructure.Duration_t.INFINITE
final Duration_t autopurge_disposed_samples_delay |
Maximum duration for which the com.rti.dds.subscription.DataReader will maintain samples for an instance once its instance_state
becomes com.rti.dds.subscription.InstanceStateKind.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE.
After this time elapses, the com.rti.dds.subscription.DataReader will purge all samples for the instance.
[default] com.rti.dds.infrastructure.Duration_t.INFINITE
[range] [1 nanosec, 1 year] or com.rti.dds.infrastructure.Duration_t.INFINITE