Polish default content type change

Issue: SPR-15367

spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java

@@ -233,7 +233,17 @@ public class ContentNegotiationManagerFactoryBean
 	 * <p>By default this is not set.
 	 * @see #setDefaultContentTypeStrategy
 	 */
-	public void setDefaultContentType(List<MediaType> contentTypes) {
+	public void setDefaultContentType(MediaType contentType) {
+		this.defaultNegotiationStrategy = new FixedContentNegotiationStrategy(contentType);
+	}
+
+	/**
+	 * Set the default content types to use when no content type is requested.
+	 * <p>By default this is not set.
+	 * @see #setDefaultContentTypeStrategy
+	 * @since 5.0
+	 */
+	public void setDefaultContentTypes(List<MediaType> contentTypes) {
 		this.defaultNegotiationStrategy = new FixedContentNegotiationStrategy(contentTypes);
 	}
 

spring-web/src/main/java/org/springframework/web/accept/FixedContentNegotiationStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -16,12 +16,14 @@
 
 package org.springframework.web.accept;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
 import org.springframework.http.MediaType;
+import org.springframework.util.Assert;
 import org.springframework.web.context.request.NativeWebRequest;
 
 /**
@@ -38,22 +40,30 @@ public class FixedContentNegotiationStrategy implements ContentNegotiationStrate
 
 
 	/**
-	 * Create an instance with the given content type.
+	 * Constructor with a single default {@code MediaType}.
 	 */
-	public FixedContentNegotiationStrategy(MediaType... contentTypes) {
-		this.contentTypes = Arrays.asList(contentTypes);
+	public FixedContentNegotiationStrategy(MediaType contentType) {
+		this(Collections.singletonList(contentType));
 	}
-	
+
 	/**
-	 * Create an instance with the given content type.
-	 * 
-	 * <p>
-	 * List is ordered in the same manner as a "quality" parameter on incoming requests.
-	 * If destinations which do not support any of the media types provided are present,
-	 * end the list with {@link MediaType#ALL} to allow standard media type determination
+	 * Constructor with an ordered List of default {@code MediaType}'s to return
+	 * for use in applications that support a variety of content types.
+	 * <p>Consider appending {@link MediaType#ALL} at the end if destinations
+	 * are present which do not support any of the other default media types.
+	 * @since 5.0
 	 */
 	public FixedContentNegotiationStrategy(List<MediaType> contentTypes) {
-		this.contentTypes = contentTypes;
+		Assert.notNull(contentTypes, "'contentTypes' must not be null");
+		this.contentTypes = Collections.unmodifiableList(contentTypes);
+	}
+
+
+	/**
+	 * Return the configured list of media types.
+	 */
+	public List<MediaType> getContentTypes() {
+		return this.contentTypes;
 	}
 
 
@@ -62,7 +72,6 @@ public class FixedContentNegotiationStrategy implements ContentNegotiationStrate
 		if (logger.isDebugEnabled()) {
 			logger.debug("Requested media types: " + this.contentTypes);
 		}
-		
 		return this.contentTypes;
 	}
 

spring-web/src/test/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBeanTests.java

@@ -19,6 +19,7 @@ package org.springframework.web.accept;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.junit.Before;
@@ -161,35 +162,31 @@ public class ContentNegotiationManagerFactoryBeanTests {
 
 		assertEquals(Collections.<MediaType>emptyList(), manager.resolveMediaTypes(this.webRequest));
 	}
-	
+
 	@Test
 	public void setDefaultContentType() throws Exception {
-		this.factoryBean.setDefaultContentType(Arrays.asList(MediaType.APPLICATION_JSON));
+		this.factoryBean.setDefaultContentType(MediaType.APPLICATION_JSON);
 		this.factoryBean.afterPropertiesSet();
 		ContentNegotiationManager manager = this.factoryBean.getObject();
 
-		assertEquals(Collections.singletonList(MediaType.APPLICATION_JSON),
-				manager.resolveMediaTypes(this.webRequest));
+		assertEquals(MediaType.APPLICATION_JSON, manager.resolveMediaTypes(this.webRequest).get(0));
 
 		// SPR-10513
 		this.servletRequest.addHeader("Accept", MediaType.ALL_VALUE);
-		assertEquals(Collections.singletonList(MediaType.APPLICATION_JSON),
-				manager.resolveMediaTypes(this.webRequest));
+		assertEquals(MediaType.APPLICATION_JSON, manager.resolveMediaTypes(this.webRequest).get(0));
 	}
-	
-	@Test
-	public void setMultipleDefaultContentTypess() throws Exception {
-		this.factoryBean.setDefaultContentType(Arrays.asList(MediaType.APPLICATION_JSON, MediaType.ALL));
+
+	@Test // SPR-15367
+	public void setDefaultContentTypes() throws Exception {
+		List<MediaType> mediaTypes = Arrays.asList(MediaType.APPLICATION_JSON, MediaType.ALL);
+		this.factoryBean.setDefaultContentTypes(mediaTypes);
 		this.factoryBean.afterPropertiesSet();
 		ContentNegotiationManager manager = this.factoryBean.getObject();
 
-		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON, MediaType.ALL),
-				manager.resolveMediaTypes(this.webRequest));
+		assertEquals(mediaTypes, manager.resolveMediaTypes(this.webRequest));
 
-		// SPR-15367
 		this.servletRequest.addHeader("Accept", MediaType.ALL_VALUE);
-		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON, MediaType.ALL),
-				manager.resolveMediaTypes(this.webRequest));
+		assertEquals(mediaTypes, manager.resolveMediaTypes(this.webRequest));
 	}
 
 	@Test  // SPR-12286

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ContentNegotiationConfigurer.java

@@ -219,19 +219,18 @@ public class ContentNegotiationConfigurer {
 	}
 
 	/**
-	 * Set the default content type to use when no content type is requested.
-	 * <p>
-	 * Media types are ordered in the same manner as a "quality" parameter on incoming
-	 * requests. If destinations which do not support any of the media types provided are
-	 * present, end the list with {@link MediaType#ALL} to allow standard media type
-	 * determination
-	 * <p>
-	 * By default this is not set.
-	 * 
+	 * Set the default content type(s) to use when no content type is requested
+	 * in order of priority.
+	 *
+	 * <p>If destinations are present that do not support any of the given media
+	 * types, consider appending {@link MediaType#ALL} at the end.
+	 *
+	 * <p>By default this is not set.
+	 *
 	 * @see #defaultContentTypeStrategy
 	 */
 	public ContentNegotiationConfigurer defaultContentType(MediaType... defaultContentTypes) {
-		this.factory.setDefaultContentType(Arrays.asList(defaultContentTypes));
+		this.factory.setDefaultContentTypes(Arrays.asList(defaultContentTypes));
 		return this;
 	}
 

spring-webmvc/src/test/java/org/springframework/web/servlet/config/annotation/ContentNegotiationConfigurerTests.java

@@ -20,6 +20,7 @@ import java.util.Collections;
 
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.http.MediaType;
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.web.accept.ContentNegotiationManager;
@@ -27,7 +28,7 @@ import org.springframework.web.accept.FixedContentNegotiationStrategy;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.ServletWebRequest;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
 
 /**
  * Test fixture for {@link ContentNegotiationConfigurer} tests.
@@ -55,7 +56,7 @@ public class ContentNegotiationConfigurerTests {
 		this.servletRequest.setRequestURI("/flower.gif");
 
 		assertEquals("Should be able to resolve file extensions by default",
-				Arrays.asList(MediaType.IMAGE_GIF), manager.resolveMediaTypes(this.webRequest));
+				MediaType.IMAGE_GIF, manager.resolveMediaTypes(this.webRequest).get(0));
 
 		this.servletRequest.setRequestURI("/flower?format=gif");
 		this.servletRequest.addParameter("format", "gif");
@@ -67,7 +68,7 @@ public class ContentNegotiationConfigurerTests {
 		this.servletRequest.addHeader("Accept", MediaType.IMAGE_GIF_VALUE);
 
 		assertEquals("Should resolve Accept header by default",
-				Arrays.asList(MediaType.IMAGE_GIF), manager.resolveMediaTypes(this.webRequest));
+				MediaType.IMAGE_GIF, manager.resolveMediaTypes(this.webRequest).get(0));
 	}
 
 	@Test
@@ -76,7 +77,7 @@ public class ContentNegotiationConfigurerTests {
 		ContentNegotiationManager manager = this.configurer.getContentNegotiationManager();
 
 		this.servletRequest.setRequestURI("/flower.json");
-		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+		assertEquals(MediaType.APPLICATION_JSON, manager.resolveMediaTypes(this.webRequest).get(0));
 	}
 
 	@Test
@@ -89,7 +90,7 @@ public class ContentNegotiationConfigurerTests {
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.addParameter("f", "json");
 
-		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+		assertEquals(MediaType.APPLICATION_JSON, manager.resolveMediaTypes(this.webRequest).get(0));
 	}
 
 	@Test
@@ -108,9 +109,9 @@ public class ContentNegotiationConfigurerTests {
 		this.configurer.defaultContentType(MediaType.APPLICATION_JSON);
 		ContentNegotiationManager manager = this.configurer.getContentNegotiationManager();
 
-		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+		assertEquals(MediaType.APPLICATION_JSON, manager.resolveMediaTypes(this.webRequest).get(0));
 	}
-	
+
 	@Test
 	public void setMultipleDefaultContentTypes() throws Exception {
 		this.configurer.defaultContentType(MediaType.APPLICATION_JSON, MediaType.ALL);
@@ -124,6 +125,6 @@ public class ContentNegotiationConfigurerTests {
 		this.configurer.defaultContentTypeStrategy(new FixedContentNegotiationStrategy(MediaType.APPLICATION_JSON));
 		ContentNegotiationManager manager = this.configurer.getContentNegotiationManager();
 
-		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+		assertEquals(MediaType.APPLICATION_JSON, manager.resolveMediaTypes(this.webRequest).get(0));
 	}
 }