Expose underlying DynamoDbClient from DynamoDbEnhancedClient interface (#6772)

* Expose underlying DynamoDbClient from DynamoDbEnhancedClient interface

* Aditional changes in tests

* Modify changelog

Author: S-Saranya1

.changes/next-release/feature-AmazonDynamoDBEnhancedClient-d608437.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "Amazon DynamoDB Enhanced Client",
+    "contributor": "",
+    "description": "Added dynamoDbClient() and dynamoDbAsyncClient() default methods to DynamoDbEnhancedClient and DynamoDbEnhancedAsyncClient interfaces to allow access to the underlying low-level client. Fixes [#6654](https://github.com/aws/aws-sdk-java-v2/issues/6654)"
+}

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/DynamoDbEnhancedAsyncClient.java

@@ -527,6 +527,20 @@ default CompletableFuture<TransactWriteItemsEnhancedResponse> transactWriteItems
         throw new UnsupportedOperationException();
     }
 
+    /**
+     * Returns the underlying low-level {@link DynamoDbAsyncClient} that this enhanced client uses to make API calls.
+     * <p>
+     * The returned client is the same instance that was provided during construction via
+     * {@link Builder#dynamoDbClient(DynamoDbAsyncClient)}, or the internally-created one if {@link #create()} was used.
+     * It is <b>not</b> a copy — any operations performed on it (including {@code close()}) will affect this
+     * enhanced client as well.
+     *
+     * @return the underlying {@link DynamoDbAsyncClient}
+     * @throws UnsupportedOperationException if the implementation does not support this operation
+     */
+    default DynamoDbAsyncClient dynamoDbAsyncClient() {
+        throw new UnsupportedOperationException();
+    }
 
     /**
      * Creates a default builder for {@link DynamoDbEnhancedAsyncClient}.

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/DynamoDbEnhancedClient.java

@@ -537,6 +537,21 @@ default TransactWriteItemsEnhancedResponse transactWriteItemsWithResponse(
         throw new UnsupportedOperationException();
     }
 
+    /**
+     * Returns the underlying low-level {@link DynamoDbClient} that this enhanced client uses to make API calls.
+     * <p>
+     * The returned client is the same instance that was provided during construction via
+     * {@link Builder#dynamoDbClient(DynamoDbClient)}, or the internally-created one if {@link #create()} was used.
+     * It is <b>not</b> a copy — any operations performed on it (including {@code close()}) will affect this
+     * enhanced client as well.
+     *
+     * @return the underlying {@link DynamoDbClient}
+     * @throws UnsupportedOperationException if the implementation does not support this operation
+     */
+    default DynamoDbClient dynamoDbClient() {
+        throw new UnsupportedOperationException();
+    }
+
     /**
      * Creates a default builder for {@link DynamoDbEnhancedClient}.
      */

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/client/DefaultDynamoDbEnhancedAsyncClient.java

@@ -132,6 +132,7 @@ public CompletableFuture<TransactWriteItemsEnhancedResponse> transactWriteItemsW
         return transactWriteItemsWithResponse(builder.build());
     }
 
+    @Override
     public DynamoDbAsyncClient dynamoDbAsyncClient() {
         return dynamoDbClient;
     }

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/client/DefaultDynamoDbEnhancedClient.java

@@ -126,6 +126,7 @@ public TransactWriteItemsEnhancedResponse transactWriteItemsWithResponse(
         return transactWriteItemsWithResponse(builder.build());
     }
 
+    @Override
     public DynamoDbClient dynamoDbClient() {
         return dynamoDbClient;
     }

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/internal/client/DefaultDynamoDbEnhancedAsyncClientTest.java

@@ -15,6 +15,8 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.client;
 
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
@@ -26,6 +28,8 @@
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
+import software.amazon.awssdk.enhanced.dynamodb.DynamoDbAsyncTable;
+import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedAsyncClient;
 import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension;
 import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
 import software.amazon.awssdk.enhanced.dynamodb.extensions.VersionedRecordExtension;
@@ -117,4 +121,22 @@ public void toBuilder() {
 
         assertThat(copiedObject, is(dynamoDbEnhancedAsyncClient));
     }
+
+    @Test
+    public void dynamoDbAsyncClient_viaInterface_returnsSameInstance() {
+        DynamoDbEnhancedAsyncClient client = dynamoDbEnhancedAsyncClient;
+        assertThat(client.dynamoDbAsyncClient()).isSameAs(mockDynamoDbAsyncClient);
+    }
+
+    @Test
+    public void dynamoDbAsyncClient_defaultMethod_throwsUnsupportedOperationException() {
+        DynamoDbEnhancedAsyncClient bareClient = new DynamoDbEnhancedAsyncClient() {
+            @Override
+            public <T> DynamoDbAsyncTable<T> table(String tableName, TableSchema<T> tableSchema) {
+                return null;
+            }
+        };
+        assertThatThrownBy(() -> bareClient.dynamoDbAsyncClient())
+            .isInstanceOf(UnsupportedOperationException.class);
+    }
 }

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/internal/client/DefaultDynamoDbEnhancedClientTest.java

@@ -15,6 +15,8 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.client;
 
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
@@ -25,7 +27,9 @@
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
+import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClient;
 import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension;
+import software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable;
 import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
 import software.amazon.awssdk.enhanced.dynamodb.extensions.VersionedRecordExtension;
 import software.amazon.awssdk.enhanced.dynamodb.internal.extensions.ChainExtension;
@@ -116,4 +120,22 @@ public void toBuilder() {
 
         assertThat(copiedObject, is(dynamoDbEnhancedClient));
     }
+
+    @Test
+    public void dynamoDbClient_viaInterface_returnsSameInstance() {
+        DynamoDbEnhancedClient client = dynamoDbEnhancedClient;
+        assertThat(client.dynamoDbClient()).isSameAs(mockDynamoDbClient);
+    }
+
+    @Test
+    public void dynamoDbClient_defaultMethod_throwsUnsupportedOperationException() {
+        DynamoDbEnhancedClient bareClient = new DynamoDbEnhancedClient() {
+            @Override
+            public <T> DynamoDbTable<T> table(String tableName, TableSchema<T> tableSchema) {
+                return null;
+            }
+        };
+        assertThatThrownBy(() -> bareClient.dynamoDbClient())
+            .isInstanceOf(UnsupportedOperationException.class);
+    }
 }