ISubscriber, IWaiter and ISubscriberRunner interfaces

August 2, 2023

ID messagebus_component_isubwait

The ISubscriber, IWaiter, and ISubscriberRunner interfaces provide the methods enabling the subscriber to receive messages from the bus and process them.

Descriptions of the ISubscriber, IWaiter and ISubscriberRunner interfaces are provided in the file named messagebus/i_subscriber.h.

The IProviderFactory interface is used to obtain instances of the IWaiter and ISubscriberRunner interfaces. The implementation of the ISubscriber callback interface is provided by the subscriber application.

Receiving a message from the bus

You can use the IWaiter::Wait() or ISubscriberRunner::Run() method to switch a subscriber to standby mode, waiting for a message from the bus. These methods accept the bus client ID and the pointer to the ISubscriber callback interface. If the client ID is not registered, the call will be declined.

It is not recommended to use the IWaiter interface, because calling the IWaiter::Wait() method is a locking call.

The ISubscriber::OnMessage() method will be called when a message is received from the bus. This method accepts the message subject and message ID.

i_subscriber.h (fragment)

class ISubscriber

{

...

virtual fdn::ResultCode OnMessage(const std::string& topic, BundleId id) = 0;

};

...

class IWaiter

{

...

[[deprecated("Use ISubscriberRunner::Run method instead.")]]

virtual fdn::ResultCode Wait(ClientId id, const ISubscriberPtr& subscriberPtr) = 0;

};

...

class ISubscriberRunner

{

...

virtual fdn::ResultCode Run(ClientId id, const ISubscriberPtr& subscriberPtr) = 0;

};

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