[Hackathon] Add support for async doesBucketExist & doesObjectExist (#3075)

* [Hackathon] Add support for async doesBucketExist & doesObjectExist

Author: Bennett Lynch

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/interceptor/DefaultFailedExecutionContext.java

@@ -15,8 +15,9 @@
 
 package software.amazon.awssdk.core.internal.interceptor;
 
+import static software.amazon.awssdk.utils.CompletableFutureUtils.unwrap;
+
 import java.util.Optional;
-import java.util.concurrent.CompletionException;
 import software.amazon.awssdk.annotations.SdkInternalApi;
 import software.amazon.awssdk.core.SdkRequest;
 import software.amazon.awssdk.core.SdkResponse;
@@ -43,13 +44,6 @@ private DefaultFailedExecutionContext(Builder builder) {
         this.interceptorContext = Validate.paramNotNull(builder.interceptorContext, "interceptorContext");
     }
 
-    private Throwable unwrap(Throwable exception) {
-        while (exception instanceof CompletionException) {
-            exception = exception.getCause();
-        }
-        return exception;
-    }
-
     @Override
     public SdkRequest request() {
         return interceptorContext.request();

services-custom/s3-transfer-manager/src/main/java/software/amazon/awssdk/transfer/s3/internal/progress/TransferListenerFailedContext.java

@@ -15,7 +15,8 @@
 
 package software.amazon.awssdk.transfer.s3.internal.progress;
 
-import java.util.concurrent.CompletionException;
+import static software.amazon.awssdk.utils.CompletableFutureUtils.unwrap;
+
 import software.amazon.awssdk.annotations.Immutable;
 import software.amazon.awssdk.annotations.SdkInternalApi;
 import software.amazon.awssdk.transfer.s3.TransferObjectRequest;
@@ -45,13 +46,6 @@ private TransferListenerFailedContext(Builder builder) {
         this.transferContext = Validate.paramNotNull(builder.transferContext, "transferContext");
     }
 
-    private Throwable unwrap(Throwable exception) {
-        while (exception instanceof CompletionException) {
-            exception = exception.getCause();
-        }
-        return exception;
-    }
-
     public static Builder builder() {
         return new Builder();
     }

services/s3/src/it/java/software/amazon/awssdk/services/s3/extensions/DefaultS3ExtensionIntegrationTest.java

@@ -48,22 +48,42 @@ public static void tearDownFixture() {
     }
 
     @Test
-    public void bucketExists() {
+    public void bucketExistsSync() {
         assertThat(s3.doesBucketExist(BUCKET)).isTrue();
     }
 
     @Test
-    public void bucketDoesNotExist() {
+    public void bucketExistsAsync() {
+        assertThat(s3Async.doesBucketExist(BUCKET).join()).isTrue();
+    }
+
+    @Test
+    public void bucketDoesNotExistSync() {
         assertThat(s3.doesBucketExist(temporaryBucketName("noexist"))).isFalse();
     }
 
     @Test
-    public void objectExists() {
+    public void bucketDoesNotExistAsync() {
+        assertThat(s3Async.doesBucketExist(temporaryBucketName("noexist")).join()).isFalse();
+    }
+
+    @Test
+    public void objectExistsSync() {
         assertThat(s3.doesObjectExist(BUCKET, KEY)).isTrue();
     }
 
     @Test
-    public void objectDoesNotExist() {
+    public void objectExistsAsync() {
+        assertThat(s3Async.doesObjectExist(BUCKET, KEY).join()).isTrue();
+    }
+
+    @Test
+    public void objectDoesNotExistSync() {
         assertThat(s3.doesObjectExist(BUCKET, "noexist")).isFalse();
     }
+
+    @Test
+    public void objectDoesNotExistAsync() {
+        assertThat(s3Async.doesObjectExist(BUCKET, "noexist").join()).isFalse();
+    }
 }

services/s3/src/main/java/software/amazon/awssdk/services/s3/extensions/S3AsyncClientSdkExtension.java

@@ -19,6 +19,7 @@
 import software.amazon.awssdk.annotations.SdkExtensionMethod;
 import software.amazon.awssdk.annotations.SdkPublicApi;
 import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.internal.extensions.DefaultS3AsyncClientSdkExtension;
 import software.amazon.awssdk.services.s3.model.S3Exception;
 
 /**
@@ -40,21 +41,21 @@ public interface S3AsyncClientSdkExtension {
      */
     @SdkExtensionMethod
     default CompletableFuture<Boolean> doesBucketExist(String bucket) {
-        throw new UnsupportedOperationException("not implemented yet");
+        return new DefaultS3AsyncClientSdkExtension((S3AsyncClient) this).doesBucketExist(bucket);
     }
 
     /**
      * Check whether the specified object exists in Amazon S3 (and you have permission to access it). If the object exists but is
      * not accessible (e.g., due to access being denied or the bucket existing in another region), an {@link S3Exception} will be
      * thrown.
      *
-     * @param bucketName the bucket that contains the object
-     * @param key        the name of the object
+     * @param bucket the bucket that contains the object
+     * @param key    the name of the object
      * @return true if the bucket object exists and you have permission to access it; false if it does not exist
      * @throws S3Exception if the bucket exists but is not accessible
      */
     @SdkExtensionMethod
-    default CompletableFuture<Boolean> doesObjectExist(String bucketName, String key) {
-        throw new UnsupportedOperationException("not implemented yet");
+    default CompletableFuture<Boolean> doesObjectExist(String bucket, String key) {
+        return new DefaultS3AsyncClientSdkExtension((S3AsyncClient) this).doesObjectExist(bucket, key);
     }
 }

services/s3/src/main/java/software/amazon/awssdk/services/s3/extensions/S3ClientSdkExtension.java

@@ -59,14 +59,14 @@ default boolean doesBucketExist(String bucket) {
      * not accessible (e.g., due to access being denied or the bucket existing in another region), an {@link S3Exception} will be
      * thrown.
      *
-     * @param bucketName the bucket that contains the object
+     * @param bucket the bucket that contains the object
      * @param key the name of the object
      * @return true if the bucket object exists and you have permission to access it; false if it does not exist
      * @throws S3Exception if the bucket exists but is not accessible
      */
     @SdkExtensionMethod
-    default boolean doesObjectExist(String bucketName, String key) {
-        return new DefaultS3ClientSdkExtension((S3Client) this).doesObjectExist(bucketName, key);
+    default boolean doesObjectExist(String bucket, String key) {
+        return new DefaultS3ClientSdkExtension((S3Client) this).doesObjectExist(bucket, key);
     }
 
     /**

services/s3/src/main/java/software/amazon/awssdk/services/s3/internal/extensions/DefaultS3AsyncClientSdkExtension.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.services.s3.internal.extensions;
+
+import static software.amazon.awssdk.utils.CompletableFutureUtils.failedFuture;
+import static software.amazon.awssdk.utils.CompletableFutureUtils.forwardExceptionTo;
+import static software.amazon.awssdk.utils.CompletableFutureUtils.unwrap;
+
+import java.util.concurrent.CompletableFuture;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.extensions.S3AsyncClientSdkExtension;
+import software.amazon.awssdk.services.s3.model.HeadBucketResponse;
+import software.amazon.awssdk.services.s3.model.HeadObjectResponse;
+import software.amazon.awssdk.services.s3.model.NoSuchBucketException;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
+import software.amazon.awssdk.utils.Validate;
+
+public class DefaultS3AsyncClientSdkExtension implements S3AsyncClientSdkExtension {
+
+    private final S3AsyncClient s3;
+
+    public DefaultS3AsyncClientSdkExtension(S3AsyncClient s3) {
+        this.s3 = Validate.notNull(s3, "s3");
+    }
+
+    @Override
+    public CompletableFuture<Boolean> doesBucketExist(String bucket) {
+        try {
+            Validate.notEmpty(bucket, "bucket");
+            CompletableFuture<Boolean> returnFuture = new CompletableFuture<>();
+            CompletableFuture<HeadBucketResponse> responseFuture = s3.headBucket(r -> r.bucket(bucket));
+            forwardExceptionTo(returnFuture, responseFuture);
+            responseFuture.whenComplete((r, t) -> {
+                t = unwrap(t);
+                if (t == null) {
+                    returnFuture.complete(true);
+                } else if (t instanceof NoSuchBucketException) {
+                    returnFuture.complete(false);
+                } else {
+                    returnFuture.completeExceptionally(t);
+                }
+            });
+            return returnFuture;
+        } catch (Throwable t) {
+            return failedFuture(t);
+        }
+    }
+
+    @Override
+    public CompletableFuture<Boolean> doesObjectExist(String bucket, String key) {
+        try {
+            Validate.notEmpty(bucket, "bucket");
+            Validate.notEmpty(bucket, "key");
+            CompletableFuture<Boolean> returnFuture = new CompletableFuture<>();
+            CompletableFuture<HeadObjectResponse> responseFuture = s3.headObject(r -> r.bucket(bucket).key(key));
+            forwardExceptionTo(returnFuture, responseFuture);
+            responseFuture.whenComplete((r, t) -> {
+                t = unwrap(t);
+                if (t == null) {
+                    returnFuture.complete(true);
+                } else if (t instanceof NoSuchKeyException) {
+                    returnFuture.complete(false);
+                } else {
+                    returnFuture.completeExceptionally(t);
+                }
+            });
+            return returnFuture;
+        } catch (Throwable t) {
+            return failedFuture(t);
+        }
+    }
+}

services/s3/src/main/java/software/amazon/awssdk/services/s3/internal/extensions/DefaultS3ClientSdkExtension.java

@@ -44,8 +44,8 @@ public boolean doesBucketExist(String bucket) {
 
     @Override
     public boolean doesObjectExist(String bucket, String key) {
-        Validate.notNull(bucket, "bucket");
-        Validate.notNull(bucket, "key");
+        Validate.notEmpty(bucket, "bucket");
+        Validate.notEmpty(bucket, "key");
         try {
             s3.headObject(r -> r.bucket(bucket).key(key));
             return true;

utils/src/main/java/software/amazon/awssdk/utils/CompletableFutureUtils.java

@@ -144,4 +144,15 @@ public static <SourceT, DestT> CompletableFuture<SourceT> forwardTransformedResu
 
         return src;
     }
+
+    /**
+     * Unwrap a {@link Throwable} provided by a {@link CompletableFuture} to discard the {@link CompletionException} and retrieve
+     * the underlying exception.
+     */
+    public static Throwable unwrap(Throwable exception) {
+        while (exception instanceof CompletionException) {
+            exception = exception.getCause();
+        }
+        return exception;
+    }
 }