Adding namespace and missing exists methods

sdk/servicebus/azure-messaging-servicebus/src/main/java/com/azure/messaging/servicebus/ServiceBusManagementAsyncClient.java

@@ -6,6 +6,7 @@
 import com.azure.core.annotation.ReturnType;
 import com.azure.core.annotation.ServiceClient;
 import com.azure.core.annotation.ServiceMethod;
+import com.azure.core.exception.AzureException;
 import com.azure.core.exception.ClientAuthenticationException;
 import com.azure.core.exception.HttpResponseException;
 import com.azure.core.exception.ResourceExistsException;
@@ -31,6 +32,7 @@
 import com.azure.messaging.servicebus.implementation.models.CreateSubscriptionBodyContent;
 import com.azure.messaging.servicebus.implementation.models.CreateTopicBody;
 import com.azure.messaging.servicebus.implementation.models.CreateTopicBodyContent;
+import com.azure.messaging.servicebus.implementation.models.NamespacePropertiesEntry;
 import com.azure.messaging.servicebus.implementation.models.QueueDescriptionEntry;
 import com.azure.messaging.servicebus.implementation.models.QueueDescriptionFeed;
 import com.azure.messaging.servicebus.implementation.models.ResponseLink;
@@ -40,6 +42,7 @@
 import com.azure.messaging.servicebus.implementation.models.SubscriptionDescriptionFeed;
 import com.azure.messaging.servicebus.implementation.models.TopicDescriptionEntry;
 import com.azure.messaging.servicebus.implementation.models.TopicDescriptionFeed;
+import com.azure.messaging.servicebus.models.NamespaceProperties;
 import com.azure.messaging.servicebus.models.QueueDescription;
 import com.azure.messaging.servicebus.models.QueueRuntimeInfo;
 import com.azure.messaging.servicebus.models.SubscriptionDescription;
@@ -457,6 +460,40 @@ public Mono<Response<QueueDescription>> getQueueWithResponse(String queueName) {
         return withContext(context -> getQueueWithResponse(queueName, context, Function.identity()));
     }
 
+    /**
+     * Gets whether or not a queue with {@code queueName} exists in the Service Bus namespace.
+     *
+     * @param queueName Name of the queue.
+     *
+     * @return A Mono that completes indicating whether or not the queue exists.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     * @throws IllegalArgumentException if {@code queueName} is an empty string.
+     * @throws NullPointerException if {@code queueName} is null.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Boolean> getQueueExists(String queueName) {
+        return getQueueExistsWithResponse(queueName).map(Response::getValue);
+    }
+
+    /**
+     * Gets whether or not a queue with {@code queueName} exists in the Service Bus namespace.
+     *
+     * @param queueName Name of the queue.
+     *
+     * @return A Mono that completes indicating whether or not the queue exists along with its HTTP response.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     * @throws IllegalArgumentException if {@code queueName} is an empty string.
+     * @throws NullPointerException if {@code queueName} is null.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Response<Boolean>> getQueueExistsWithResponse(String queueName) {
+        return getEntityExistsWithResponse(getQueueWithResponse(queueName));
+    }
+
     /**
      * Gets runtime information about the queue.
      *
@@ -495,6 +532,31 @@ public Mono<Response<QueueRuntimeInfo>> getQueueRuntimeInfoWithResponse(String q
         return withContext(context -> getQueueWithResponse(queueName, context, QueueRuntimeInfo::new));
     }
 
+    /**
+     * Gets information about the Service Bus namespace.
+     *
+     * @return A Mono that completes with information about the Service Bus namespace.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to the namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<NamespaceProperties> getNamespaceProperties() {
+        return getNamespacePropertiesWithResponse().map(Response::getValue);
+    }
+
+    /**
+     * Gets information about the Service Bus namespace along with its HTTP response.
+     *
+     * @return A Mono that completes with information about the namespace and the associated HTTP response.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Response<NamespaceProperties>> getNamespacePropertiesWithResponse() {
+        return withContext(this::getNamespacePropertiesWithResponse);
+    }
+
     /**
      * Gets information about the queue.
      *
@@ -537,6 +599,42 @@ public Mono<Response<SubscriptionDescription>> getSubscriptionWithResponse(Strin
             Function.identity()));
     }
 
+    /**
+     * Gets whether or not a subscription within a topic exists.
+     *
+     * @param topicName Name of topic associated with subscription.
+     * @param subscriptionName Name of the subscription.
+     *
+     * @return A Mono that completes indicating whether or not the subscription exists.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     * @throws IllegalArgumentException if {@code subscriptionName} is an empty string.
+     * @throws NullPointerException if {@code subscriptionName} is null.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Boolean> getSubscriptionExists(String topicName, String subscriptionName) {
+        return getSubscriptionExistsWithResponse(topicName, subscriptionName).map(Response::getValue);
+    }
+
+    /**
+     * Gets whether or not a subscription within a topic exists.
+     *
+     * @param topicName Name of topic associated with subscription.
+     * @param subscriptionName Name of the subscription.
+     *
+     * @return A Mono that completes indicating whether or not the subscription exists along with its HTTP response.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     * @throws IllegalArgumentException if {@code subscriptionName} is an empty string.
+     * @throws NullPointerException if {@code subscriptionName} is null.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Response<Boolean>> getSubscriptionExistsWithResponse(String topicName, String subscriptionName) {
+        return getEntityExistsWithResponse(getSubscriptionWithResponse(topicName, subscriptionName));
+    }
+
     /**
      * Gets runtime information about the subscription.
      *
@@ -619,6 +717,40 @@ public Mono<Response<TopicDescription>> getTopicWithResponse(String topicName) {
         return withContext(context -> getTopicWithResponse(topicName, context, Function.identity()));
     }
 
+    /**
+     * Gets whether or not a topic with {@code topicName} exists in the Service Bus namespace.
+     *
+     * @param topicName Name of the topic.
+     *
+     * @return A Mono that completes indicating whether or not the topic exists.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     * @throws IllegalArgumentException if {@code topicName} is an empty string.
+     * @throws NullPointerException if {@code topicName} is null.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Boolean> getTopicExists(String topicName) {
+        return getTopicExistsWithResponse(topicName).map(Response::getValue);
+    }
+
+    /**
+     * Gets whether or not a topic with {@code topicName} exists in the Service Bus namespace.
+     *
+     * @param topicName Name of the topic.
+     *
+     * @return A Mono that completes indicating whether or not the topic exists along with its HTTP response.
+     * @throws ClientAuthenticationException if the client's credentials do not have access to modify the
+     *     namespace.
+     * @throws HttpResponseException If error occurred processing the request.
+     * @throws IllegalArgumentException if {@code topicName} is an empty string.
+     * @throws NullPointerException if {@code topicName} is null.
+     */
+    @ServiceMethod(returns = ReturnType.SINGLE)
+    public Mono<Response<Boolean>> getTopicExistsWithResponse(String topicName) {
+        return getEntityExistsWithResponse(getTopicWithResponse(topicName));
+    }
+
     /**
      * Gets runtime information about the topic.
      *
@@ -1135,6 +1267,31 @@ Mono<Response<Void>> deleteTopicWithResponse(String topicName, Context context)
         }
     }
 
+    /**
+     * Gets whether an entity exists.
+     *
+     * @param getEntityOperation Operation to get information about entity. If {@link ResourceNotFoundException} is
+     *     thrown, then it is mapped to false.
+     * @param <T> Entity type.
+     *
+     * @return True if the entity exists, false otherwise.
+     */
+    <T> Mono<Response<Boolean>> getEntityExistsWithResponse(Mono<Response<T>> getEntityOperation) {
+        return getEntityOperation.map(response -> {
+            // When an entity does not exist, it does not have any description object in it.
+            final boolean exists = response.getValue() != null;
+            return (Response<Boolean>) new SimpleResponse<>(response.getRequest(), response.getStatusCode(),
+                response.getHeaders(), exists);
+        })
+            .onErrorResume(ResourceNotFoundException.class, exception -> {
+                final HttpResponse response = exception.getResponse();
+                final Response<Boolean> result = new SimpleResponse<>(response.getRequest(), response.getStatusCode(),
+                    response.getHeaders(), false);
+
+                return Mono.just(result);
+            });
+    }
+
     /**
      * Gets a queue with its context.
      *
@@ -1226,6 +1383,30 @@ <T> Mono<Response<T>> getSubscriptionWithResponse(String topicName, String subsc
         }
     }
 
+    /**
+     * Gets the namespace properties with its context.
+     *
+     * @param context Context to pass into request.
+     *
+     * @return A Mono that completes with the {@link NamespaceProperties}.
+     */
+    Mono<Response<NamespaceProperties>> getNamespacePropertiesWithResponse(Context context) {
+        return managementClient.getNamespaces().getWithResponseAsync(context).handle((response, sink) -> {
+            final NamespacePropertiesEntry entry = response.getValue();
+            if (entry == null || entry.getContent() == null) {
+                sink.error(new AzureException(
+                    "There was no content inside namespace response. Entry: " + response));
+                return;
+            }
+
+            final NamespaceProperties namespaceProperties = entry.getContent().getNamespaceProperties();
+            final Response<NamespaceProperties> result = new SimpleResponse<>(response.getRequest(),
+                response.getStatusCode(), response.getHeaders(), namespaceProperties);
+
+            sink.next(result);
+        });
+    }
+
     /**
      * Gets a topic with its context.
      *
@@ -1541,7 +1722,7 @@ private Response<QueueDescription> deserializeQueue(Response<Object> response) {
         if (entry == null) {
             return new SimpleResponse<>(response.getRequest(), response.getStatusCode(), response.getHeaders(), null);
         } else if (entry.getContent() == null) {
-            logger.info("entry.getContent() is null. There should have been content returned. Entry: {}", entry);
+            logger.info("entry.getContent() is null. The entity may not exist. {}", entry);
             return new SimpleResponse<>(response.getRequest(), response.getStatusCode(), response.getHeaders(), null);
         }