Event hub java docs

guides/messaging/event-broker.md

@@ -40,8 +40,12 @@ The following guide is based on a productive (paid) account on SAP BTP.
 This guide describes the end-to-end process of developing a stand-alone (or "single tenant") CAP application that consumes messages via SAP Cloud Application Event Hub.
 The guide uses SAP S/4HANA as the event emitter, but this is a stand-in for any system that is able to publish CloudEvents via SAP Cloud Application Event Hub.
 
+<div class="impl node">
+
 Sample app: [@capire/incidents with Customers based on S/4's Business Partners](https://github.com/cap-js/incidents-app/tree/event-broker)
 
+</div>
+
 
 ### Prerequisite: Events & Messaging in CAP
 
@@ -72,10 +76,18 @@ However, please note that future [Open Resource Discovery (ORD)](https://sap.git
 
 Configure your application to use the messaging service kind `event-broker` (derived from SAP Cloud Application Event Hub's technical name).
 
-[Learn more about configuring SAP Cloud Application Event Hub in CAP Node.js](../../node.js/messaging#event-broker){.learn-more}
+<div class="impl node">
 
+[Learn more about configuring SAP Cloud Application Event Hub in CAP Node.js](../../node.js/messaging#event-broker){.learn-more}
 [Learn more about `cds.env` profiles](../../node.js/cds-env#profiles){.learn-more}
 
+</div>
+<div class="impl java">
+
+[Learn more about configuring SAP Cloud Application Event Hub in CAP Java](../../java/messaging#configuring-sap-event-hub-support){.learn-more}
+
+</div>
+
 ::: tip Local Testing
 Since SAP Cloud Application Event Hub sends events via HTTP, you won't be able to receive events on your local machine unless you use a tunneling service. Therefore we recommend to use a messaging service of kind [`local-messaging`](../../node.js/messaging#local-messaging) for local testing.
 :::

java/messaging.md

@@ -280,11 +280,73 @@ Besides the built-in support for `local-messaging` and `file-based-messaging`, a
 ```yaml [srv/src/main/resources/application.yaml]
 cds:
   messaging.services:
-  - name: "messaging-name"
+  - name: "messaging-kind"
     kind: "enterprise-messaging"
 ```
 :::
 
+
+#### Configuring SAP Cloud Application Event Hub Support: <Beta/> { #configuring-sap-event-hub-support}
+
+To do asynchronous communication using [SAP Cloud Application Event Hub](https://help.sap.com/docs/event-broker), the feature dependency must be added:
+
+```xml [srv/pom.xml]
+<dependency>
+  <groupId>com.sap.cds</groupId>
+  <artifactId>cds-feature-event-hub</artifactId>
+  <scope>runtime</scope>
+</dependency>
+```
+
+Additionally it can be configured in the `application.yaml` file:
+
+```yaml [srv/src/main/resources/application.yaml]
+cds:
+  messaging.services:
+  - name: "eventhub-messaging"
+    kind: "event-hub"
+    binding: "event-broker"
+```
+
+The [CloudEvents](https://cloudevents.io/) format is enforced since it's required by SAP Cloud Application Event Hub.
+
+Authentication in the SAP Cloud Application Event Hub integration is based on the [Identity Authentication service (IAS)](https://help.sap.com/docs/cloud-identity-services/cloud-identity-services/getting-started-with-identity-service-of-sap-btp) of [SAP Cloud Identity Services](https://help.sap.com/docs/cloud-identity-services).
+
+**Deployment:**
+
+Your SAP Cloud Application Event Hub configuration must include your system namespace as well as the webhook URL. The binding parameters must set `"authentication-type": "X509_GENERATED"` to allow IAS-based authentication. Your IAS instance must be configured to include your SAP Cloud Application Event Hub instance under consumed-services in order for your application to accept requests from SAP Cloud Application Event Hub. Here's an example configuration
+
+```yaml [mta.yaml]
+  - name: eventhub-messaging
+    requires:
+      - name: ...
+    type: org.cloudfoundry.managed-service
+    parameters:
+      service: event-broker
+      service-plan: event-connectivity
+      config:
+        # unique identifier for this event broker instance
+        # should start with own namespace (i.e., "foo.bar") and may not be longer than 15 characters
+        systemNamespace: cap.service
+        webhookUrl: ~{srv-api/srv-cert-url}/messaging/v1.0/eb
+  - name: eventhub-messaging-ias
+    type: org.cloudfoundry.managed-service
+    parameters:
+      service: identity
+      service-plan: application
+      config:
+        consumed-services:
+          - service-instance-name: eventhub-messaging
+        display-name: cap.service #> any value, e.g., reuse MTA ID
+        home-url: ~{incidents-srv-api/url}
+    requires:
+      - name: eventhub-messaging
+    processed-after:
+      - eventhub-messaging
+```
+
+<span id="aftereventhub" />
+
 <span id="beforeredispubsub" />
 
 #### Configuring Redis PubSub Support <Beta />: { #configuring-redis-pubsub-support-beta}
@@ -680,7 +742,7 @@ private void handleError(MessagingErrorEventContext ctx) {
 }
 ```
 
-In a multi-tenant setup with several microservices, messages of a tenant not yet subscribed to the own microservice would be already received from the message queue. In this case, the message cannot be processed for the tenant because the tenant context is not yet available. By default, the standard error handler still acknowledges the message to prevent it from getting stuck in the message sequence. To change this behavior, the custom error handler from the example above can be extended by checking the exception type of the unknown tenant. 
+In a multi-tenant setup with several microservices, messages of a tenant not yet subscribed to the own microservice would be already received from the message queue. In this case, the message cannot be processed for the tenant because the tenant context is not yet available. By default, the standard error handler still acknowledges the message to prevent it from getting stuck in the message sequence. To change this behavior, the custom error handler from the example above can be extended by checking the exception type of the unknown tenant.
 
 
 ```java
@@ -692,15 +754,15 @@ private void handleError(MessagingErrorEventContext ctx) {
       errorCode.equals(CdsErrorStatuses.INVALID_DATA_FORMAT.getCodeString())) {
       // error handling for infrastructure error
       ctx.setResult(false); // no acknowledgement
-    
+
     } else if (errorCode.equals(CdsErrorStatuses.TENANT_NOT_EXISTS.getCodeString())) {
       // error handling for unknown tenant context
-      
+
        // tenant of the received message
       String tenant = ctx.getTenant();
 
       // received message
-      Map<String, Object> headers = ctx.getMessageHeaders(); 
+      Map<String, Object> headers = ctx.getMessageHeaders();
       Map<String, Object> message = ctx.getMessageData();
 
       ctx.setResult(true); // acknowledge

node.js/messaging.md

@@ -240,7 +240,7 @@ In addition to that, slashes in the event name are replaced by dots and the `sou
 Examples:
 
 | publishPrefix            | derived source      |
-|--------------------------|---------------------|
+| ------------------------ | ------------------- |
 | `my/own/namespace/ce/`   | `/my/own/namespace` |
 | `my/own.namespace/-/ce/` | `/my/own.namespace` |