Polishing in ErrorResponse

See gh-30566

spring-web/src/main/java/org/springframework/web/ErrorResponse.java

@@ -64,6 +64,9 @@ public interface ErrorResponse {
 	 */
 	ProblemDetail getBody();
 
+
+	// MessageSource codes and arguments
+
 	/**
 	 * Return a code to use to resolve the problem "type" for this exception
 	 * through a {@link MessageSource}. The type resolved through the
@@ -76,6 +79,15 @@ public interface ErrorResponse {
 		return getDefaultTypeMessageCode(getClass());
 	}
 
+	/**
+	 * Return a code to use to resolve the problem "title" for this exception
+	 * through a {@link MessageSource}.
+	 * <p>By default this is initialized via {@link #getDefaultTitleMessageCode(Class)}.
+	 */
+	default String getTitleMessageCode() {
+		return getDefaultTitleMessageCode(getClass());
+	}
+
 	/**
 	 * Return a code to use to resolve the problem "detail" for this exception
 	 * through a {@link MessageSource}.
@@ -111,15 +123,6 @@ public interface ErrorResponse {
 		return getDetailMessageArguments();
 	}
 
-	/**
-	 * Return a code to use to resolve the problem "title" for this exception
-	 * through a {@link MessageSource}.
-	 * <p>By default this is initialized via {@link #getDefaultTitleMessageCode(Class)}.
-	 */
-	default String getTitleMessageCode() {
-		return getDefaultTitleMessageCode(getClass());
-	}
-
 	/**
 	 * Use the given {@link MessageSource} to resolve the
 	 * {@link #getTypeMessageCode() type}, {@link #getTitleMessageCode() title},
@@ -159,6 +162,16 @@ public interface ErrorResponse {
 		return "problemDetail.type." + exceptionType.getName();
 	}
 
+	/**
+	 * Build a message code for the "title" field, for the given exception type.
+	 * @param exceptionType the exception type associated with the problem
+	 * @return {@code "problemDetail.title."} followed by the fully qualified
+	 * {@link Class#getName() class name}
+	 */
+	static String getDefaultTitleMessageCode(Class<?> exceptionType) {
+		return "problemDetail.title." + exceptionType.getName();
+	}
+
 	/**
 	 * Build a message code for the "detail" field, for the given exception type.
 	 * @param exceptionType the exception type associated with the problem
@@ -171,15 +184,6 @@ public interface ErrorResponse {
 		return "problemDetail." + exceptionType.getName() + (suffix != null ? "." + suffix : "");
 	}
 
-	/**
-	 * Build a message code for the "title" field, for the given exception type.
-	 * @param exceptionType the exception type associated with the problem
-	 * @return {@code "problemDetail.title."} followed by the fully qualified
-	 * {@link Class#getName() class name}
-	 */
-	static String getDefaultTitleMessageCode(Class<?> exceptionType) {
-		return "problemDetail.title." + exceptionType.getName();
-	}
 
 	/**
 	 * Static factory method to build an instance via
@@ -229,33 +233,6 @@ public interface ErrorResponse {
 		 */
 		Builder headers(Consumer<HttpHeaders> headersConsumer);
 
-		/**
-		 * Set the underlying {@link ProblemDetail#setDetail(String) detail}.
-		 * @return the same builder instance
-		 */
-		Builder detail(String detail);
-
-		/**
-		 * Customize the {@link MessageSource} code for looking up the value for
-		 * the underlying {@link #detail(String) detail}.
-		 * <p>By default, this is set to
-		 * {@link ErrorResponse#getDefaultDetailMessageCode(Class, String)} with the
-		 * associated Exception type.
-		 * @param messageCode the message code to use
-		 * @return the same builder instance
-		 * @see ErrorResponse#getDetailMessageCode()
-		 */
-		Builder detailMessageCode(String messageCode);
-
-		/**
-		 * Set the arguments to provide to the {@link MessageSource} lookup for
-		 * {@link #detailMessageCode(String)}.
-		 * @param messageArguments the arguments to provide
-		 * @return the same builder instance
-		 * @see ErrorResponse#getDetailMessageArguments()
-		 */
-		Builder detailMessageArguments(Object... messageArguments);
-
 		/**
 		 * Set the underlying {@link ProblemDetail#setType(URI) type} field.
 		 * @return the same builder instance
@@ -286,6 +263,33 @@ public interface ErrorResponse {
 		 */
 		Builder instance(@Nullable URI instance);
 
+		/**
+		 * Set the underlying {@link ProblemDetail#setDetail(String) detail}.
+		 * @return the same builder instance
+		 */
+		Builder detail(String detail);
+
+		/**
+		 * Customize the {@link MessageSource} code for looking up the value for
+		 * the underlying {@link #detail(String) detail}.
+		 * <p>By default, this is set to
+		 * {@link ErrorResponse#getDefaultDetailMessageCode(Class, String)} with the
+		 * associated Exception type.
+		 * @param messageCode the message code to use
+		 * @return the same builder instance
+		 * @see ErrorResponse#getDetailMessageCode()
+		 */
+		Builder detailMessageCode(String messageCode);
+
+		/**
+		 * Set the arguments to provide to the {@link MessageSource} lookup for
+		 * {@link #detailMessageCode(String)}.
+		 * @param messageArguments the arguments to provide
+		 * @return the same builder instance
+		 * @see ErrorResponse#getDetailMessageArguments()
+		 */
+		Builder detailMessageArguments(Object... messageArguments);
+
 		/**
 		 * Set a "dynamic" {@link ProblemDetail#setProperty(String, Object)
 		 * property} on the underlying {@code ProblemDetail}.

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityExceptionHandlerTests.java

@@ -127,37 +127,35 @@ public class ResponseEntityExceptionHandlerTests {
 
 	@Test
 	void errorResponseProblemDetailViaMessageSource() {
-
 		Locale locale = Locale.UK;
-		LocaleContextHolder.setLocale(locale);
 
 		String type = "https://example.com/probs/unsupported-content";
 		String title = "Media type is not valid or not supported";
+		Class<UnsupportedMediaTypeStatusException> exceptionType = UnsupportedMediaTypeStatusException.class;
 
-		StaticMessageSource messageSource = new StaticMessageSource();
-		messageSource.addMessage(
-				ErrorResponse.getDefaultDetailMessageCode(UnsupportedMediaTypeStatusException.class, null), locale,
+		StaticMessageSource source = new StaticMessageSource();
+		source.addMessage(ErrorResponse.getDefaultTypeMessageCode(exceptionType), locale, type);
+		source.addMessage(ErrorResponse.getDefaultTitleMessageCode(exceptionType), locale, title);
+		source.addMessage(ErrorResponse.getDefaultDetailMessageCode(exceptionType, null), locale,
 				"Content-Type {0} not supported. Supported: {1}");
-		messageSource.addMessage(
-				ErrorResponse.getDefaultTitleMessageCode(UnsupportedMediaTypeStatusException.class), locale, title);
-		messageSource.addMessage(
-				ErrorResponse.getDefaultTypeMessageCode(UnsupportedMediaTypeStatusException.class), locale, type);
 
-		this.exceptionHandler.setMessageSource(messageSource);
+		this.exceptionHandler.setMessageSource(source);
 
-		Exception ex = new UnsupportedMediaTypeStatusException(MediaType.APPLICATION_JSON,
-				List.of(MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_XML));
+		Exception ex = new UnsupportedMediaTypeStatusException(
+				MediaType.APPLICATION_JSON, List.of(MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_XML));
 
 		MockServerWebExchange exchange = MockServerWebExchange.from(
 				MockServerHttpRequest.get("/").acceptLanguageAsLocales(locale).build());
 
 		ResponseEntity<?> responseEntity = this.exceptionHandler.handleException(ex, exchange).block();
+		assertThat(responseEntity).isNotNull();
 
-		ProblemDetail body = (ProblemDetail) responseEntity.getBody();
-		assertThat(body.getDetail()).isEqualTo(
+		ProblemDetail problem = (ProblemDetail) responseEntity.getBody();
+		assertThat(problem).isNotNull();
+		assertThat(problem.getType()).isEqualTo(URI.create(type));
+		assertThat(problem.getTitle()).isEqualTo(title);
+		assertThat(problem.getDetail()).isEqualTo(
 				"Content-Type application/json not supported. Supported: [application/atom+xml, application/xml]");
-		assertThat(body.getTitle()).isEqualTo(title);
-		assertThat(body.getType()).isEqualTo(URI.create(type));
 	}
 
 	@Test

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/ResponseEntityExceptionHandlerTests.java

@@ -161,33 +161,31 @@ public class ResponseEntityExceptionHandlerTests {
 
 	@Test
 	public void errorResponseProblemDetailViaMessageSource() {
-
-		Locale locale = Locale.UK;
-		LocaleContextHolder.setLocale(locale);
-
-		String type = "https://example.com/probs/unsupported-content";
-		String title = "Media type is not valid or not supported";
-
 		try {
-			StaticMessageSource messageSource = new StaticMessageSource();
-			messageSource.addMessage(
-					ErrorResponse.getDefaultDetailMessageCode(HttpMediaTypeNotSupportedException.class, null), locale,
-					"Content-Type {0} not supported. Supported: {1}");
-			messageSource.addMessage(
-					ErrorResponse.getDefaultTitleMessageCode(HttpMediaTypeNotSupportedException.class), locale, title);
-			messageSource.addMessage(
-					ErrorResponse.getDefaultTypeMessageCode(HttpMediaTypeNotSupportedException.class), locale, type);
+			Locale locale = Locale.UK;
+			LocaleContextHolder.setLocale(locale);
 
-			this.exceptionHandler.setMessageSource(messageSource);
+			String type = "https://example.com/probs/unsupported-content";
+			String title = "Media type is not valid or not supported";
+			Class<HttpMediaTypeNotSupportedException> exceptionType = HttpMediaTypeNotSupportedException.class;
+
+			StaticMessageSource source = new StaticMessageSource();
+			source.addMessage(ErrorResponse.getDefaultTypeMessageCode(exceptionType), locale, type);
+			source.addMessage(ErrorResponse.getDefaultTitleMessageCode(exceptionType), locale, title);
+			source.addMessage(ErrorResponse.getDefaultDetailMessageCode(exceptionType, null), locale,
+					"Content-Type {0} not supported. Supported: {1}");
+
+			this.exceptionHandler.setMessageSource(source);
 
 			ResponseEntity<?> entity = testException(new HttpMediaTypeNotSupportedException(
 					MediaType.APPLICATION_JSON, List.of(MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_XML)));
 
-			ProblemDetail body = (ProblemDetail) entity.getBody();
-			assertThat(body.getDetail()).isEqualTo(
+			ProblemDetail problem = (ProblemDetail) entity.getBody();
+			assertThat(problem).isNotNull();
+			assertThat(problem.getType()).isEqualTo(URI.create(type));
+			assertThat(problem.getTitle()).isEqualTo(title);
+			assertThat(problem.getDetail()).isEqualTo(
 					"Content-Type application/json not supported. Supported: [application/atom+xml, application/xml]");
-			assertThat(body.getTitle()).isEqualTo(title);
-			assertThat(body.getType()).isEqualTo(URI.create(type));
 		}
 		finally {
 			LocaleContextHolder.resetLocaleContext();