Add ResponseEntity.ofNullable()

To deal with non-Optional nullable objects.

Closes spring-projectsgh-29117

spring-web/src/main/java/org/springframework/http/ResponseEntity.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -68,6 +68,7 @@
  *
  * @author Arjen Poutsma
  * @author Brian Clozel
+ * @author Sebastien Deleuze
  * @since 3.0.2
  * @param <T> the body type
  * @see #getStatusCode()
@@ -284,6 +285,21 @@ public <T> ResponseEntity<T> build() {
 		};
 	}
 
+	/**
+	 * A shortcut for creating a {@code ResponseEntity} with the given body
+	 * and the {@linkplain HttpStatus#OK OK} status, or an empty body and a
+	 * {@linkplain HttpStatus#NOT_FOUND NOT FOUND} status in case of a
+	 * {@code null} parameter.
+	 * @return the created {@code ResponseEntity}
+	 * @since 6.0.5
+	 */
+	public static <T> ResponseEntity<T> ofNullable(@Nullable T body) {
+		if (body == null) {
+			return notFound().build();
+		}
+		return ResponseEntity.ok(body);
+	}
+
 	/**
 	 * Create a new builder with a {@linkplain HttpStatus#CREATED CREATED} status
 	 * and a location header set to the given URI.

spring-web/src/test/java/org/springframework/http/ResponseEntityTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@
  * @author Arjen Poutsma
  * @author Marcel Overdijk
  * @author Kazuki Shimizu
+ * @author Sebastien Deleuze
  */
 class ResponseEntityTests {
 
@@ -90,6 +91,25 @@ void ofEmptyOptional() {
 		assertThat(responseEntity.getBody()).isNull();
 	}
 
+	@Test
+	void ofNullable() {
+		Integer entity = 42;
+		ResponseEntity<Integer> responseEntity = ResponseEntity.ofNullable(entity);
+
+		assertThat(responseEntity).isNotNull();
+		assertThat(responseEntity.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat((int) responseEntity.getBody()).isEqualTo((int) entity);
+	}
+
+	@Test
+	void ofNullNullable() {
+		ResponseEntity<Integer> responseEntity = ResponseEntity.ofNullable(null);
+
+		assertThat(responseEntity).isNotNull();
+		assertThat(responseEntity.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND);
+		assertThat(responseEntity.getBody()).isNull();
+	}
+
 	@Test
 	void createdLocation() {
 		URI location = URI.create("location");

spring-web/src/test/kotlin/org/springframework/http/KotlinResponseEntityTests.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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 org.springframework.http
+
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.Test
+
+/**
+ * Kotlin tests for [ResponseEntity].
+ *
+ * @author Sebastien Deleuze
+ */
+class KotlinResponseEntityTests {
+
+	@Test
+	fun ofNullable() {
+		val entity = 42
+		val responseEntity = ResponseEntity.ofNullable(entity)
+		Assertions.assertThat(responseEntity).isNotNull()
+		Assertions.assertThat(responseEntity.statusCode).isEqualTo(HttpStatus.OK)
+		Assertions.assertThat(responseEntity.body as Int).isEqualTo(entity)
+	}
+
+	@Test
+	fun ofNullNullable() {
+		val responseEntity = ResponseEntity.ofNullable<Int>(null)
+		Assertions.assertThat(responseEntity).isNotNull()
+		Assertions.assertThat(responseEntity.statusCode).isEqualTo(HttpStatus.NOT_FOUND)
+		Assertions.assertThat(responseEntity.body).isNull()
+	}
+
+}