Subscriber (gateway-framework-api 2.2.0 API)

```
public interface Subscriber
```
A subscriber to be used to subscribe to or unsubscribe from Diffusion topics. This can be used to subscribe to Diffusion topics as required, if auto subscription is disabled for the service by setting SinkHandler.SinkServiceProperties.autoSubscribe() to false.

Since:

2.0

Author:

DiffusionData Limited

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`String`	`getConfiguredDiffusionTopicSelector()` Returns the configured `diffusionTopicSelector` in the framework configuration of the service.
`CompletableFuture<?>`	`subscribe()` Request subscription to configured topics in the Diffusion server.
`CompletableFuture<?>`	`subscribe(String topics)` Request subscription to passed topics in the Diffusion server.
`CompletableFuture<?>`	`unsubscribe(String topics)` Request unsubscription to topics from the Diffusion server.

- Method Detail
  - subscribe
```
CompletableFuture<?> subscribe()
```
    Request subscription to configured topics in the Diffusion server.
    Returns:
    a CompletableFuture that completes when a response is received from the Diffusion server after subscription.
    If the task completes successfully, the CompletableFuture result will be null. The result type is any rather than Void to provide forward compatibility with future iterations of this API that may provide a non-null result with a more specific result type.
    If the task fails, the CompletableFuture will complete exceptionally with a CompletionException. Common reasons for failure, listed by the exception reported as the cause, include:
    
    DiffusionSecurityException – if the application principal does not have sufficient permissions to perform the operation;
    DiffusionClientException – if some other exception has been returned from the Diffusion server via the Diffusion Client API. The cause will provide more detail.
    ServiceStateException – if the service state is incompatible with the operation.
  - subscribe
```
CompletableFuture<?> subscribe(String topics)
```
    Request subscription to passed topics in the Diffusion server.
    Parameters:
    
    topics - the topics to subscribe to. This can be a single topic path or a Diffusion topic selector. A topic selector is an expression that identifies one or more topics.
    See https://docs .diffusiondata.com/cloud/latest/manual/html/designguide/data /publication/topic_selector_unified.html for more details.
    
    Returns:
    a CompletableFuture that completes when a response is received from the Diffusion server after subscription.
    If the task completes successfully, the CompletableFuture result will be null. The result type is any rather than Void to provide forward compatibility with future iterations of this API that may provide a non-null result with a more specific result type.
    If the task fails, the CompletableFuture will complete exceptionally with a CompletionException. Common reasons for failure, listed by the exception reported as the cause, include:
    
    DiffusionSecurityException – if the application principal does not have sufficient permissions to perform the operation;
    DiffusionClientException – if some other exception has been returned from the Diffusion server via the Diffusion Client API. The cause will provide more detail.
    ServiceStateException – if the service state is incompatible with the operation.
    Throws:
    
    IllegalArgumentException - if topics is an invalid topic selector expression
  - unsubscribe
```
CompletableFuture<?> unsubscribe(String topics)
```
    Request unsubscription to topics from the Diffusion server.
    Parameters:
    
    topics - the topics to unsubscribe from. This can be a single topic path or a Diffusion topic selector. A topic selector is an expression that identifies one or more topics.
    See https://docs .diffusiondata.com/cloud/latest/manual/html/designguide/data /publication/topic_selector_unified.html for more details.
    
    Returns:
    a CompletableFuture that completes when a response is received from the Diffusion server after unsubscription.
    If the task completes successfully, the CompletableFuture result will be null. The result type is any rather than Void to provide forward compatibility with future iterations of this API that may provide a non-null result with a more specific result type.
    If the task fails, the CompletableFuture will complete exceptionally with a CompletionException. Common reasons for failure, listed by the exception reported as the cause, include:
    
    DiffusionClientException – if some other exception has been returned from the Diffusion server via the Diffusion Client API. The cause will provide more detail.
    ServiceStateException – if the service state is incompatible with the operation.
    Throws:
    
    IllegalArgumentException - if topics is an invalid topic selector expression
  - getConfiguredDiffusionTopicSelector
```
String getConfiguredDiffusionTopicSelector()
```
    Returns the configured diffusionTopicSelector in the framework configuration of the service.
    If not configured, a null value will be returned.
    This method can be used to check if the diffusionTopicSelector is configured by an application user.
    
    Returns:
    
    the configured diffusionTopicSelector in the framework configuration, or null if not configured.

Interface Subscriber

Method Summary

Method Detail

subscribe

subscribe

unsubscribe

getConfiguredDiffusionTopicSelector