RTI Connext Java API Version 7.1.0
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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 |
Minimum 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.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE. More... | |
final Duration_t | autopurge_disposed_samples_delay |
Minimum 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.NOT_ALIVE_DISPOSED_INSTANCE_STATE. More... | |
final Duration_t | autopurge_disposed_instances_delay |
<<extension>> Minimum duration for which the com.rti.dds.subscription.DataReader will maintain information about a received instance once its instance_state becomes com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE and there are no samples for the instance in the DataReader queue. More... | |
final Duration_t | autopurge_nowriter_instances_delay |
<<extension>> Minimum duration for which the com.rti.dds.subscription.DataReader will maintain information about a received instance once its instance_state becomes com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE and there are no samples for the instance in the DataReader queue. More... | |
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final QosPolicyId_t | id |
The ID of this QoS policy. More... | |
final String | policy_name |
The name of this QoS policy. More... | |
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.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.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE or com.rti.dds.subscription.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.
A DataReader can also reclaim all resources for instances that have an instance state of com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE and for which all DDS samples have been 'taken'. DataReaders will only reclaim resources in this situation when the autopurge_disposed_instances_delay has been set to zero.
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 |
Minimum 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.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE.
At some point after this time elapses, the com.rti.dds.subscription.DataReader will purge all internal information regarding the instance, any "untaken" samples will also be dropped.
[default] com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE
[range] [1 nanosec, 1 year] or com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE
final Duration_t autopurge_disposed_samples_delay |
Minimum 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.NOT_ALIVE_DISPOSED_INSTANCE_STATE.
After this time elapses, the com.rti.dds.subscription.DataReader will purge all samples for the instance even if they have not been read by the application. This purge is done lazily when space is needed for other samples or instances.
[default] com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE
[range] [1 nanosec, 1 year] or com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE
final Duration_t autopurge_disposed_instances_delay |
<<extension>> Minimum duration for which the com.rti.dds.subscription.DataReader will maintain information about a received instance once its instance_state
becomes com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE and there are no samples for the instance in the DataReader queue.
After this time elapses, when the last sample for the disposed instance is taken, the com.rti.dds.subscription.DataReader will keep only the minimum state about the instance.
If you do not want to keep this minimum state after the delay period, also set keep_minimum_state_for_instances to FALSE in com.rti.dds.infrastructure.DataReaderResourceLimitsQosPolicy.
The only currently supported values are com.rti.dds.infrastructure.Duration_t.ZERO and com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE. A value of com.rti.dds.infrastructure.Duration_t.ZERO will purge an instance's state immediately after the instance state transitions to com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_DISPOSED_INSTANCE_STATE, as long as all samples, including the dispose sample, associated with that instance have been 'taken'.
[default] com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE
final Duration_t autopurge_nowriter_instances_delay |
<<extension>> Minimum duration for which the com.rti.dds.subscription.DataReader will maintain information about a received instance once its instance_state
becomes com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE and there are no samples for the instance in the DataReader queue.
An instance will transition to the com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE instance_state
when all known writers for the instance have either lost liveliness or have unregistered themselves from the instance. After this time elapses, when the last sample for the instance without writers is taken, the com.rti.dds.subscription.DataReader will keep only the minimum state about the instance.
If you do not want to keep this minimum state after the delay period, also set keep_minimum_state_for_instances to FALSE in com.rti.dds.infrastructure.DataReaderResourceLimitsQosPolicy.
The only currently supported values are com.rti.dds.infrastructure.Duration_t.ZERO and com.rti.dds.infrastructure.Duration_t.DURATION_INFINITE. A value of com.rti.dds.infrastructure.Duration_t.ZERO will purge an instance's state immediately after the instance state transitions to com.rti.dds.subscription.InstanceStateKind.NOT_ALIVE_NO_WRITERS_INSTANCE_STATE, as long as all samples, including the no_writers sample, associated with that instance have been 'taken'.
[default] com.rti.dds.infrastructure.Duration_t.ZERO