Replier< TRequest, TReply > Class Template Reference

Allows receiving requests and sending replies. More...

Inherits IDisposable.

Public Member Functions
void	SendReply (TReply reply, SampleIdentity relatedRequestId)
	Sends a reply to a specific request identified by a SampleIdentity. More...
void	SendReply (TReply reply, SampleInfo relatedRequestInfo)
	Sends a reply to a specific request identified by a SampleInfo. More...
void	SendReply (TReply reply, WriteParams writeParams)
	Sends a reply. More...
bool	WaitForRequests (int minCount, Duration maxWait)
	Wait for a number of requests for a duration of time. More...
async Task< int >	WaitForRequestsAsync (int minCount=1, CancellationToken cancellationToken=default)
	Wait for a number of requests asynchronously until a minimum number of requests reach the Replier, or a cancellation is requested using a CancellationToken. More...
LoanedSamples< TRequest >	ReceiveRequests (int minCount, Duration maxWait)
	Receives a number of requests. More...
LoanedSamples< TRequest >	TakeRequests ()
	Takes all requests. More...
LoanedSamples< TRequest >	ReadRequests ()
	Reads all requests. More...
void	ResetEvents ()
	Stop notifying of RequestsAvailable events and remove all its event handlers. More...
uint	GetMatchedRequesterCount ()
	Gets the number of Requester's that are currently matched with this Replier. More...
void	Dispose ()
	Releases the native resources used by this object. More...

Properties
DataReader< TRequest >	RequestReader [get]
	The underlying DataReader<TRequest> used to read requests. More...
DataWriter< TReply >	ReplyWriter [get]
	The underlying DataWriter<TReply> used to send replies. More...
Action< Replier< TRequest, TReply > >	RequestsAvailable
	Event triggered new requests are available on the Replier. More...

Detailed Description

Allows receiving requests and sending replies.

Template Parameters

TRequest	The type of the requests to be received.
TReply	The type of the replies to be sent.

A Replier is an entity with two associated topics: a request topic and a reply topic. It can receive requests by subscribing to the request topic and can send replies to those requests by publishing the reply topic.

Valid types for these topics are: those generated by the rtiddsgen code generator, the DDS built-in types and Rti.Types.Dynamic.DynamicData.

A Replier has four main types of operations:

• Waiting for requests to be received from the middleware.
• Getting those requests.
• Receiving requests (a convenience operation that is a combination of waiting and getting in a single operation).
• Sending a reply for a previously received request (i.e., publishing a reply sample on the reply topic with special meta-data so that the original Requester can identify it).

For multi-reply scenarios in which a Replier generates more than one reply for a request, the Replier should mark all the intermediate replies (all but the last) using the SampleFlags.IntermediateReplySequence flag in Rti.Dds.Subscription.SampleInfo.Flag.

A Replier has an associated Rti.Dds.Domain.DomainParticipant, which can be shared with other requesters or RTI Connext routines. All the other RTI Connext entities required for the request-reply interaction, including a DataWriter<TReply> for writing replies and a DataReader<TRequest> for reading requests, are automatically created when the replier is constructed.

Quality of Service for the underlying DataWriter and DataReader can be configured (see ReplierBuilder<TRequest, TReply>.WithDataWriterQos and ReplierBuilder<TRequest, TReply>.WithDataReaderQos). By default, they are created with Rti.Dds.Core.Policy.ReliabilityKind.Reliable. The exact default QoS configuration is described in the Modern C++ API: Configuring Request-Reply QoS profiles.

There are several ways to use a Replier:

• A thread receives requests and then dispatches them. If the computation of a reply is a simple operation, consider using a SimpleReplier instead of a Replier.
• Polling without waiting, using Replier<TRequest, TReply>.TakeRequests directly.
• Using an event handler that gets triggered when new requests are available (see Replier<TRequest, TReply>.RequestsAvailable).

Use participant.BuildReplier<TRequest, TReply>() (an extension method defined in DomainParticipantRequestReplyExtensions) to configure and build a Replier.

For example, to create a basic Replier:

var replier = participant.BuildReplier<FooRequest, FooReply>()
        .WithServiceName("FooService")
        .Create();

See also Request-Reply Examples.

Member Function Documentation

Dispose()

void Dispose

(

)

Releases the native resources used by this object.

GetMatchedRequesterCount()

uint GetMatchedRequesterCount

(

)

Gets the number of Requester's that are currently matched with this Replier.

Returns

The number of matching Requester's.

ReadRequests()

LoanedSamples<TRequest> ReadRequests

(

)

Reads all requests.

Returns

A LoanedSamples<TRequest> object containing the requests.

ReceiveRequests()

LoanedSamples<TRequest> ReceiveRequests	(	int	minCount,
		Duration	maxWait
	)

Receives a number of requests.

Parameters

minCount	The minimum number of requests to wait for.
maxWait	Maximum time to wait for the requests.

Returns

A LoanedSamples<TRequest> object containing the requests.

ResetEvents()

void ResetEvents

(

)

Stop notifying of RequestsAvailable events and remove all its event handlers.

SendReply() [1/3]

void SendReply	(	TReply	reply,
		SampleIdentity	relatedRequestId
	)

Sends a reply to a specific request identified by a SampleIdentity.

Parameters

reply	The reply to be sent.
relatedRequestId	Identifies a request previously sent by Requester<TRequest, TReply>.SendRequest(TRequest).

SendReply() [2/3]

void SendReply	(	TReply	reply,
		SampleInfo	relatedRequestInfo
	)

Sends a reply to a specific request identified by a SampleInfo.

Parameters

reply	The reply to be sent.
relatedRequestInfo	Identifies a request previously sent by Requester<TRequest, TReply>.SendRequest(TRequest).

SendReply() [3/3]

void SendReply	(	TReply	reply,
		WriteParams	writeParams
	)

Sends a reply.

Parameters

reply	The reply to be sent.
writeParams	The parameters to write the reply.

Other parameters to customize are discussed in DataWriter<T>.Write(T, WriteParams). In particular, Rti.Dds.Publication.WriteParams.Flag can be set to SampleFlags.IntermediateReplySequence to inform the Requester application that this reply will be followed by additional replies to the same request. The Requester can access the flag in Rti.Dds.Subscription.SampleInfo.Flag when it receives the reply.

TakeRequests()

LoanedSamples<TRequest> TakeRequests

(

)

Takes all requests.

Returns

A LoanedSamples<TRequest> object containing the requests.

WaitForRequests()

bool WaitForRequests	(	int	minCount,
		Duration	maxWait
	)

Wait for a number of requests for a duration of time.

Parameters

minCount	The minimum number of requests to wait for.
maxWait	Maximum time to wait for the requests.

Returns

A bool indicating whether or not the number of specified requests have reached the Replier.

WaitForRequestsAsync()

async Task<int> WaitForRequestsAsync	(	int	minCount = 1,
		CancellationToken	cancellationToken = default
	)

Wait for a number of requests asynchronously until a minimum number of requests reach the Replier, or a cancellation is requested using a CancellationToken.

Parameters

minCount	The minimum number of requests to wait for.
cancellationToken	A cancellation token for the wait.

Returns

A Task containing the number of requests that have reached the Replier while waiting.

Property Documentation

ReplyWriter

DataWriter<TReply> ReplyWriter

get

The underlying DataWriter<TReply> used to send replies.

RequestReader

DataReader<TRequest> RequestReader

get

The underlying DataReader<TRequest> used to read requests.

RequestsAvailable

Action<Replier<TRequest, TReply> > RequestsAvailable

addremove

Event triggered new requests are available on the Replier.