org.opensplice.dds.core.policy.Share Interface Reference

This QosPolicy allows sharing of entities by multiple processes or threads. More...

Inheritance diagram for org.opensplice.dds.core.policy.Share:

Collaboration diagram for org.opensplice.dds.core.policy.Share:

Public Member Functions
ServiceEnvironment	getEnvironment ()
String	getName ()
Share	withName (String name)
	Copy this policy and override the value of the property. More...

Detailed Description

This QosPolicy allows sharing of entities by multiple processes or threads.

When the policy is enabled, the data distribution service will try to look up an existing Entity that matches the name supplied in the ShareQosPolicy. A new Entity will only be created if a shared Entity registered under the specified name doesn't exist yet. Shared Readers can be useful for implementing algorithms like the worker pattern, where a single shared reader can contain samples representing different tasks that may be processed in parallel by separate processes. In this algorithm each processes consumes the task it is going to perform (i.e. it takes the sample representing that task), thus preventing other processes from consuming and therefore performing the same task.

Note: Entities can only be shared between processes if OpenSplice is running in federated mode, because it requires shared memory to communicate between the different processes. By default, the Share QosPolicy is not used. The name must be set to a valid string for the Share to be valid. This QosPolicy is applicable to DataReader and Subscriber entities, and cannot be modified after the DataReader or Subscriber is enabled. Note that a DataReader can only be shared if its Subscriber is also shared.

Definition at line 46 of file Share.java.

Member Function Documentation

getEnvironment()

ServiceEnvironment org.omg.dds.core.DDSObject.getEnvironment ( )

inherited

Returns

the org.omg.dds.core.ServiceEnvironment object that directly or indirectly was used to create this object.

Implemented in org.omg.dds.core.ServiceEnvironment, org.opensplice.dds.sub.ReflectionDataReader< TYPE, OUT_TYPE >, org.opensplice.dds.core.ModifiableTimeImpl, org.opensplice.dds.pub.ReflectionDataWriter< TYPE >, org.opensplice.dds.core.DurationImpl, org.opensplice.dds.topic.ContentFilteredTopicImpl< TYPE >, org.opensplice.dds.sub.ReadConditionImpl< TYPE >, org.opensplice.dds.core.EntityQosImpl< T extends QosPolicy >, org.opensplice.dds.type.TypeSupportImpl< TYPE >, org.opensplice.dds.topic.PublicationBuiltinTopicDataImpl, org.opensplice.dds.topic.SubscriptionBuiltinTopicDataImpl, org.opensplice.dds.topic.TopicBuiltinTopicDataImpl, org.opensplice.dds.domain.DomainParticipantFactoryImpl, org.opensplice.dds.core.QosProviderImpl, org.opensplice.dds.core.status.OfferedIncompatibleQosStatusImpl, org.opensplice.dds.core.status.RequestedIncompatibleQosStatusImpl, org.opensplice.dds.core.InstanceHandleImpl, org.opensplice.dds.core.StatusConditionImpl< T extends Entity<?, ?>, org.opensplice.dds.core.status.LivelinessChangedStatusImpl, org.opensplice.dds.core.status.PublicationMatchedStatusImpl, org.opensplice.dds.core.status.SubscriptionMatchedStatusImpl, org.opensplice.dds.sub.SampleImpl< TYPE >, org.opensplice.dds.core.policy.ShareImpl, org.opensplice.dds.core.status.OfferedDeadlineMissedStatusImpl, org.opensplice.dds.core.status.SampleRejectedStatusImpl, org.opensplice.dds.core.WaitSetImpl, org.opensplice.dds.topic.ParticipantBuiltinTopicDataImpl, org.opensplice.dds.core.status.RequestedDeadlineMissedStatusImpl, org.opensplice.dds.topic.BuiltinTopicKeyImpl, org.opensplice.dds.core.GuardConditionImpl, org.opensplice.dds.core.event.AllDataDisposedEventImpl< TYPE >, org.opensplice.dds.core.policy.QosPolicyCountImpl, org.opensplice.dds.core.status.InconsistentTopicStatusImpl, org.opensplice.dds.core.status.LivelinessLostStatusImpl, org.opensplice.dds.core.status.SampleLostStatusImpl, org.opensplice.dds.core.policy.QosPolicyImpl, org.opensplice.dds.core.status.AllDataDisposedStatusImpl, org.opensplice.dds.core.IllegalArgumentExceptionImpl, org.opensplice.dds.core.InconsistentPolicyExceptionImpl, org.opensplice.dds.core.policy.PolicyFactoryImpl, org.opensplice.dds.core.policy.TypeConsistencyEnforcementImpl, org.opensplice.dds.core.PreconditionNotMetExceptionImpl, org.opensplice.dds.core.AlreadyClosedExceptionImpl, org.opensplice.dds.core.IllegalOperationExceptionImpl, org.opensplice.dds.core.ImmutablePolicyExceptionImpl, org.opensplice.dds.core.NotEnabledExceptionImpl, org.opensplice.dds.core.OutOfResourcesExceptionImpl, org.opensplice.dds.core.DDSExceptionImpl, org.opensplice.dds.core.status.DataAvailableStatusImpl, and org.opensplice.dds.core.status.DataOnReadersStatusImpl.

getName()

String org.opensplice.dds.core.policy.Share.getName

(

)

Returns

The label used to identify the shared Entity.

Implemented in org.opensplice.dds.core.policy.ShareImpl.

withName()

Share org.opensplice.dds.core.policy.Share.withName

(

String

name

)

Copy this policy and override the value of the property.

Parameters

name	The label used to identify the shared Entity.

Returns

a new Share policy

Implemented in org.opensplice.dds.core.policy.ShareImpl.

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

• java5/common/java/code/org/opensplice/dds/core/policy/Share.java