Polishing

Closes gh-29768

spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 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.
@@ -63,15 +63,13 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 
 	/**
 	 * Constructor with a single MIME type.
-	 * @param supportedMimeType the supported MIME type
 	 */
 	protected AbstractMessageConverter(MimeType supportedMimeType) {
 		this(Collections.singletonList(supportedMimeType));
 	}
 
 	/**
-	 * Constructor with one or more MIME types via vararg.
+	 * Constructor with multiple MIME types.
-	 * @param supportedMimeTypes the supported MIME types
 	 * @since 5.2.2
 	 */
 	protected AbstractMessageConverter(MimeType... supportedMimeTypes) {
@@ -79,8 +77,7 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 	}
 
 	/**
-	 * Constructor with a Collection of MIME types.
+	 * Constructor with Collection of MIME types.
-	 * @param supportedMimeTypes the supported MIME types
 	 */
 	protected AbstractMessageConverter(Collection<MimeType> supportedMimeTypes) {
 		this.supportedMimeTypes.addAll(supportedMimeTypes);
@@ -103,20 +100,21 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 	}
 
 	/**
-	 * Configure the {@link ContentTypeResolver} to use to resolve the content
+	 * Configure a {@link ContentTypeResolver} for resolving the content type
-	 * type of an input message.
+	 * of input messages.
-	 * <p>Note that if no resolver is configured, then
+	 * <p>By default, a {@code DefaultContentTypeResolver} instance is used.
+	 * <p><strong>Note:</strong> if the resolver is set to {@code null}, then
 	 * {@link #setStrictContentTypeMatch(boolean) strictContentTypeMatch} should
-	 * be left as {@code false} (the default) or otherwise this converter will
+	 * be {@code false}, which is the default, or otherwise this converter will
 	 * ignore all messages.
-	 * <p>By default, a {@code DefaultContentTypeResolver} instance is used.
 	 */
 	public void setContentTypeResolver(@Nullable ContentTypeResolver resolver) {
 		this.contentTypeResolver = resolver;
 	}
 
 	/**
-	 * Return the configured {@link ContentTypeResolver}.
+	 * Return the {@link #setContentTypeResolver(ContentTypeResolver) configured}
+	 * {@code ContentTypeResolver}.
 	 */
 	@Nullable
 	public ContentTypeResolver getContentTypeResolver() {
@@ -125,11 +123,11 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 
 	/**
 	 * Whether this converter should convert messages for which no content type
-	 * could be resolved through the configured
+	 * can be resolved through the configured
 	 * {@link org.springframework.messaging.converter.ContentTypeResolver}.
 	 * <p>A converter can be configured to be strict only when a
 	 * {@link #setContentTypeResolver contentTypeResolver} is configured and the
-	 * list of {@link #getSupportedMimeTypes() supportedMimeTypes} is not be empty.
+	 * list of {@link #getSupportedMimeTypes() supportedMimeTypes} is not empty.
 	 * <p>When this flag is set to {@code true}, {@link #supportsMimeType(MessageHeaders)}
 	 * will return {@code false} if the {@link #setContentTypeResolver contentTypeResolver}
 	 * is not defined or if no content-type header is present.
@@ -193,7 +191,9 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 
 	@Override
 	@Nullable
-	public final Message<?> toMessage(Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint) {
+	public final Message<?> toMessage(
+			Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint) {
+
 		if (!canConvertTo(payload, headers)) {
 			return null;
 		}

spring-messaging/src/test/java/org/springframework/messaging/converter/DefaultContentTypeResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 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.
@@ -17,10 +17,8 @@
 package org.springframework.messaging.converter;
 
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.Map;
 
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.messaging.MessageHeaders;
@@ -32,67 +30,50 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 
 /**
- * Test fixture for {@link org.springframework.messaging.converter.DefaultContentTypeResolver}.
+ * Unit tests for
+ * {@link org.springframework.messaging.converter.DefaultContentTypeResolver}.
  *
  * @author Rossen Stoyanchev
  */
 public class DefaultContentTypeResolverTests {
 
-	private DefaultContentTypeResolver resolver;
+	private final DefaultContentTypeResolver resolver = new DefaultContentTypeResolver();
 
 
-	@BeforeEach
-	public void setup() {
-		this.resolver = new DefaultContentTypeResolver();
-	}
-
 	@Test
 	public void resolve() {
-		Map<String, Object> map = new HashMap<>();
+		MessageHeaders headers = headers(MimeTypeUtils.APPLICATION_JSON);
-		map.put(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_JSON);
-		MessageHeaders headers = new MessageHeaders(map);
-
 		assertThat(this.resolver.resolve(headers)).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
 	}
 
 	@Test
 	public void resolveStringContentType() {
-		Map<String, Object> map = new HashMap<>();
+		MessageHeaders headers = headers(MimeTypeUtils.APPLICATION_JSON_VALUE);
-		map.put(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_JSON_VALUE);
-		MessageHeaders headers = new MessageHeaders(map);
-
 		assertThat(this.resolver.resolve(headers)).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
 	}
 
 	@Test
 	public void resolveInvalidStringContentType() {
-		Map<String, Object> map = new HashMap<>();
+		MessageHeaders headers = headers("invalidContentType");
-		map.put(MessageHeaders.CONTENT_TYPE, "invalidContentType");
+		assertThatExceptionOfType(InvalidMimeTypeException.class).isThrownBy(() -> this.resolver.resolve(headers));
-		MessageHeaders headers = new MessageHeaders(map);
-		assertThatExceptionOfType(InvalidMimeTypeException.class).isThrownBy(() ->
-				this.resolver.resolve(headers));
 	}
 
 	@Test
 	public void resolveUnknownHeaderType() {
-		Map<String, Object> map = new HashMap<>();
+		MessageHeaders headers = headers(1);
-		map.put(MessageHeaders.CONTENT_TYPE, 1);
+		assertThatIllegalArgumentException().isThrownBy(() -> this.resolver.resolve(headers));
-		MessageHeaders headers = new MessageHeaders(map);
-		assertThatIllegalArgumentException().isThrownBy(() ->
-				this.resolver.resolve(headers));
 	}
 
 	@Test
 	public void resolveNoContentTypeHeader() {
-		MessageHeaders headers = new MessageHeaders(Collections.<String, Object>emptyMap());
+		MessageHeaders headers = new MessageHeaders(Collections.emptyMap());
-
 		assertThat(this.resolver.resolve(headers)).isNull();
 	}
 
 	@Test
 	public void resolveDefaultMimeType() {
 		this.resolver.setDefaultMimeType(MimeTypeUtils.APPLICATION_JSON);
-		MessageHeaders headers = new MessageHeaders(Collections.<String, Object>emptyMap());
+		MessageHeaders headers = new MessageHeaders(Collections.emptyMap());
 
 		assertThat(this.resolver.resolve(headers)).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
 	}
@@ -100,9 +81,11 @@ public class DefaultContentTypeResolverTests {
 	@Test
 	public void resolveDefaultMimeTypeWithNoHeader() {
 		this.resolver.setDefaultMimeType(MimeTypeUtils.APPLICATION_JSON);
-		MessageHeaders headers = null;
+		assertThat(this.resolver.resolve(null)).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
+	}
 
-		assertThat(this.resolver.resolve(headers)).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
+	private MessageHeaders headers(Object mimeType) {
+		return new MessageHeaders(Map.of(MessageHeaders.CONTENT_TYPE, mimeType));
 	}
 
 }

spring-messaging/src/test/java/org/springframework/messaging/converter/MessageConverterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 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.
@@ -138,10 +138,11 @@ public class MessageConverterTests {
 		assertThat(message.getHeaders().get(MessageHeaders.CONTENT_TYPE)).isEqualTo(MimeTypeUtils.TEXT_PLAIN);
 	}
 
-	@Test
+	@Test // gh-29768
 	public void toMessageDefaultContentType() {
 		DefaultContentTypeResolver resolver = new DefaultContentTypeResolver();
 		resolver.setDefaultMimeType(MimeTypeUtils.TEXT_PLAIN);
+
 		TestMessageConverter converter = new TestMessageConverter();
 		converter.setContentTypeResolver(resolver);
 		converter.setStrictContentTypeMatch(true);
@@ -167,16 +168,12 @@ public class MessageConverterTests {
 		}
 
 		@Override
-		protected Object convertFromInternal(
+		protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @Nullable Object hint) {
-				Message<?> message, Class<?> targetClass, @Nullable Object conversionHint) {
-
 			return "success-from";
 		}
 
 		@Override
-		protected Object convertToInternal(
+		protected Object convertToInternal(Object payload, @Nullable MessageHeaders headers, @Nullable Object hint) {
-				Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint) {
-
 			return "success-to";
 		}
 	}