dds::sub::qos::DataReaderQos Class Reference

This class provides the basic mechanism for an application to specify Quality of Service attributes for a DataReader. More...

#include "DataReaderQos.hpp"

Inherits dds::core::EntityQos< org::eclipse::cyclonedds::sub::qos::DataReaderQosDelegate >.

Public Member Functions
	DataReaderQos ()
	DataReaderQos (const DataReaderQos &qos)
	DataReaderQos (const dds::topic::qos::TopicQos &qos)
EntityQos &	operator<< (const POLICY &p)
DataReaderQos &	operator= (const dds::topic::qos::TopicQos &other)
const EntityQos &	operator>> (POLICY &p) const
POLICY &	policy ()
const POLICY &	policy () const
EntityQos &	policy (const POLICY &p)

Detailed Description

This class provides the basic mechanism for an application to specify Quality of Service attributes for a DataReader.

Attributes

QosPolicy	Desciption	Default Value
dds::core::policy::Durability	Data storage settings for late joiners (info)	Durability::Volatile()
dds::core::policy::Deadline	Period in which new sample is written (info)	Deadline::Deadline(infinite)
dds::core::policy::LatencyBudget	Used for optimization (info)	LatencyBudget::LatencyBudget(zero)
dds::core::policy::Liveliness	Liveliness assertion mechanism (info)	Liveliness::Automatic()
dds::core::policy::Reliability	Reliability settings (info)	Reliability::BestEffort()
dds::core::policy::DestinationOrder	DataReader data order settings (info)	DestinationOrder::ReceptionTimestamp()
dds::core::policy::History	Data storage settings (info)	History::KeepLast(depth 1)
dds::core::policy::ResourceLimits	Maximum resource settings (info)	ResourceLimits::ResourceLimits(all unlimited)
dds::core::policy::UserData	Additional information (info)	UserData::UserData(empty)
dds::core::policy::Ownership	Exclusive ownership or not (info)	Ownership::Shared()
dds::core::policy::TimeBasedFilter	Maximum data rate (info)	TimeBasedFilter::TimeBasedFilter(0)
dds::core::policy::ReaderDataLifecycle	Instance state changes and notifications (info)	ReaderDataLifecycle::NoAutoPurgeDisposedSamples()

A QosPolicy can be set when the DataReader is created or modified with the set qos operation. Both operations take the DataReaderQos object as a parameter. There may be cases where several policies are in conflict. Consistency checking is performed each time the policies are modified when they are being created and, in case they are already enabled, via the set qos operation.

Some QosPolicy have "immutable" semantics meaning that they can only be specified either at DataReader creation time or prior to calling the enable operation on the DataReader.

See also

DCPS_QoS

Definition at line 66 of file DataReaderQos.hpp.

Constructor & Destructor Documentation

DataReaderQos() [1/3]

dds::sub::qos::DataReaderQos::DataReaderQos ( )

inline

Create a default QoS.

Definition at line 72 of file DataReaderQos.hpp.

DataReaderQos() [2/3]

dds::sub::qos::DataReaderQos::DataReaderQos

(

const DataReaderQos &

qos

)

Create copied QoS.

Parameters

qos	the QoS to copy policies from.

DataReaderQos() [3/3]

dds::sub::qos::DataReaderQos::DataReaderQos

(

const dds::topic::qos::TopicQos &

qos

)

Create a DataReader QoS from a TopicQos.

This operation will copy the QosPolicy settings from the TopicQos to the corresponding QosPolicy settings in the DataReaderQos. The related value in DataReaderQos will be repliced, while the other policies will get the default QoS policies.

This is a "convenience" operation. It can be used to merge default DataReader QosPolicy settings with the corresponding ones on the Topic. The resulting DataReaderQos can then be used to create a new DataReader, or set its DataReaderQos.

dds::topic::qos::TopicQos topicQos = topic.qos();
dds::sub::qos::DataReaderQos readerQos(topicQos);
// Policies of the DataReaderQos that are not present in the TopicQos
// have the default value.

This operation does not check the resulting DataReaderQos for self consistency. This is because the "merged" DataReaderQos may not be the final one, as the application can still modify some QosPolicy settings prior to applying the DataReaderQos to the DataReader.

Parameters

qos	the QoS to copy policies from.

Member Function Documentation

operator<<()

EntityQos& dds::core::EntityQos::operator<< ( const POLICY &  p )

inherited

Generic function for setting a policy applicable to this QoS object. Available policies depend on the actual instantiation of the template class, which might be DomainParticipantQos, TopicQos, PublisherQos, etc.

Parameters

p	the policy to be set for this QoS instance.

operator=()

DataReaderQos& dds::sub::qos::DataReaderQos::operator=

(

const dds::topic::qos::TopicQos &

other

)

Assign dds::topic::qos::TopicQos policies to the DataReaderQos.

This operation will copy the QosPolicy settings from the TopicQos to the corresponding QosPolicy settings in the DataReaderQos (replacing the values, if present).

This is a "convenience" operation, useful in combination with the operations Subscriber::default_datareader_qos() and dds::topic::Topic::qos(). This operation can be used to merge the DataReader QosPolicy settings with the corresponding ones on the Topic. The resulting DataReaderQos can then be used to create a new DataReader, or set its DataReaderQos.

dds::topic::qos::TopicQos topicQos = topic.qos();
dds::sub::qos::DataReaderQos readerQos = subscriber.default_datareader_qos();
readerQos = topicQos;
// Policies of the DataReaderQos that are not present in the TopicQos are untouched.

This operation does not check the resulting DataReaderQos for self consistency. This is because the "merged" DataReaderQos may not be the final one, as the application can still modify some QosPolicy settings prior to applying the DataReaderQos to the DataReader.

Parameters

qos	the QoS to copy policies from.

operator>>()

const EntityQos& dds::core::EntityQos::operator>> ( POLICY &  p ) const

inherited

Generic function for obtaining the value of a specific policy belonging to this QoS instance.

Returns

policy

policy() [1/3]

POLICY& dds::core::EntityQos::policy ( )

inherited

Generic function for obtaining the value of a specific policy belonging to this QoS instance.

Returns

policy

policy() [2/3]

const POLICY& dds::core::EntityQos::policy ( ) const

inherited

Generic function for obtaining the value of a specific policy belonging to this QoS instance.

Returns

policy

policy() [3/3]

EntityQos& dds::core::EntityQos::policy ( const POLICY &  p )

inherited

Generic function for setting a policy applicable to this QoS object. Available policies depend on the actual instantiation of the template class, which might be DomainParticipantQos, TopicQos, PublisherQos, etc.

Parameters

p	the policy to be set for this QoS instance.

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The documentation for this class was generated from the following file:

• dds/sub/qos/DataReaderQos.hpp