Add example of batch context usage

Author: acogoluegnes

src/docs/asciidoc/usage.adoc

@@ -26,6 +26,21 @@ include::{test-examples}/Api.java[tag=connection-settings]
 <1> Use the `guest` user by default
 <2> Use the `admin` user for this connection
 
+=== Settling Messages in Batch
+
+.Settling messages in batch
+[source,java,indent=0]
+--------
+include::{test-examples}/Api.java[tag=settling-message-in-batch]
+--------
+<1> Declare batch context property
+<2> Create a new batch context instance
+<3> Add the current message context to the batch context if processing is successful
+<4> Settle the batch context once it contains 10 messages
+<5> Reset the batch context
+<6> Discard the current message context if processing fails
+
+
 === Subscription Listener
 
 The client provides a `SubscriptionListener` interface callback to add behavior before a subscription is created.

src/test/java/com/rabbitmq/client/amqp/docs/Api.java

@@ -86,6 +86,40 @@ void metricsCollectorMicrometerPrometheus() {
     // end::metrics-micrometer-prometheus[]
   }
 
+  void settlingMessagesInBatch() {
+    Connection connection = null;
+
+    // tag::settling-message-in-batch[]
+    Consumer.MessageHandler handler = new Consumer.MessageHandler() {
+      volatile Consumer.BatchContext batch = null;  // <1>
+      @Override
+      public void handle(Consumer.Context context, Message message) {
+        if (batch == null) {
+          batch = context.batch();  // <2>
+        }
+        boolean success = process(message);
+        if (success) {
+          batch.add(context);  // <3>
+          if (batch.size() == 10) {
+            batch.accept();  // <4>
+            batch = null;  // <5>
+          }
+        } else {
+          context.discard();  // <6>
+        }
+      }
+    };
+    Consumer consumer = connection.consumerBuilder()
+        .queue("some-queue")
+        .messageHandler(handler)
+        .build();
+    // end::settling-message-in-batch[]
+  }
+
+  boolean process(Message message) {
+    return true;
+  }
+
   void micrometerObservation() {
     ObservationRegistry observationRegistry = ObservationRegistry.NOOP;
     // tag::micrometer-observation[]