Recognize wildcards in media types with a suffix

The "includes" and "isCompatibleWith" methods of MediaType take into
account media types with suffices (e.g. application/soap+xml) including
wildcards with suffices (e.g. application/*+xml). However before this
change, the isWildcardSubtype() method returned true only for subtype
"*". Now a media type such as application/*+xml is also recognized as
having a wildcard subtype.

Issue: SPR-9841

org.springframework.web.servlet/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java

@@ -264,6 +264,28 @@ public class RequestResponseBodyMethodProcessorTests {
 		fail("Expected exception");
 	}
 
+	// SPR-9841
+
+	@Test
+	public void handleReturnValueMediaTypeSuffix() throws Exception {
+		String body = "Foo";
+		MediaType accepted = MediaType.APPLICATION_XHTML_XML;
+		List<MediaType> supported = Collections.singletonList(MediaType.valueOf("application/*+xml"));
+
+		servletRequest.addHeader("Accept", accepted);
+
+		expect(messageConverter.canWrite(String.class, null)).andReturn(true);
+		expect(messageConverter.getSupportedMediaTypes()).andReturn(supported);
+		expect(messageConverter.canWrite(String.class, accepted)).andReturn(true);
+		messageConverter.write(eq(body), eq(accepted), isA(HttpOutputMessage.class));
+		replay(messageConverter);
+
+		processor.handleReturnValue(body, returnTypeStringProduces, mavContainer, webRequest);
+
+		assertTrue(mavContainer.isRequestHandled());
+		verify(messageConverter);
+	}
+
 	// SPR-9160
 
 	@Test

org.springframework.web/src/main/java/org/springframework/http/MediaType.java

@@ -413,11 +413,12 @@ public class MediaType implements Comparable<MediaType> {
 	}
 
 	/**
-	 * Indicates whether the {@linkplain #getSubtype() subtype} is the wildcard character <code>&#42;</code> or not.
+	 * Indicates whether the {@linkplain #getSubtype() subtype} is the wildcard character <code>&#42;</code>
+	 * or the wildcard character followed by a sufiix (e.g. <code>&#42;+xml</code>), or not.
 	 * @return whether the subtype is <code>&#42;</code>
 	 */
 	public boolean isWildcardSubtype() {
-		return WILDCARD_TYPE.equals(subtype);
+		return WILDCARD_TYPE.equals(subtype) || subtype.startsWith("*+");
 	}
 
 	/**

org.springframework.web/src/test/java/org/springframework/http/MediaTypeTests.java

@@ -313,6 +313,7 @@ public class MediaTypeTests {
 		MediaType audio07 = new MediaType("audio", "*", 0.7);
 		MediaType audioBasicLevel = new MediaType("audio", "basic", Collections.singletonMap("level", "1"));
 		MediaType textHtml = new MediaType("text", "html");
+		MediaType allXml = new MediaType("application", "*+xml");
 		MediaType all = MediaType.ALL;
 
 		Comparator<MediaType> comp = MediaType.SPECIFICITY_COMPARATOR;
@@ -328,9 +329,11 @@ public class MediaTypeTests {
 		assertTrue("Invalid comparison result", comp.compare(audioBasic, audio) < 0);
 		assertTrue("Invalid comparison result", comp.compare(audioBasic, all) < 0);
 		assertTrue("Invalid comparison result", comp.compare(audio, all) < 0);
+		assertTrue("Invalid comparison result", comp.compare(MediaType.APPLICATION_XHTML_XML, allXml) < 0);
 
 		// unspecific to specific
 		assertTrue("Invalid comparison result", comp.compare(audio, audioBasic) > 0);
+		assertTrue("Invalid comparison result", comp.compare(allXml, MediaType.APPLICATION_XHTML_XML) > 0);
 		assertTrue("Invalid comparison result", comp.compare(all, audioBasic) > 0);
 		assertTrue("Invalid comparison result", comp.compare(all, audio) > 0);
 
@@ -414,6 +417,7 @@ public class MediaTypeTests {
 		MediaType audio07 = new MediaType("audio", "*", 0.7);
 		MediaType audioBasicLevel = new MediaType("audio", "basic", Collections.singletonMap("level", "1"));
 		MediaType textHtml = new MediaType("text", "html");
+		MediaType allXml = new MediaType("application", "*+xml");
 		MediaType all = MediaType.ALL;
 
 		Comparator<MediaType> comp = MediaType.QUALITY_VALUE_COMPARATOR;
@@ -429,11 +433,13 @@ public class MediaTypeTests {
 		assertTrue("Invalid comparison result", comp.compare(audioBasic, audio) < 0);
 		assertTrue("Invalid comparison result", comp.compare(audioBasic, all) < 0);
 		assertTrue("Invalid comparison result", comp.compare(audio, all) < 0);
+		assertTrue("Invalid comparison result", comp.compare(MediaType.APPLICATION_XHTML_XML, allXml) < 0);
 
 		// unspecific to specific
 		assertTrue("Invalid comparison result", comp.compare(audio, audioBasic) > 0);
 		assertTrue("Invalid comparison result", comp.compare(all, audioBasic) > 0);
 		assertTrue("Invalid comparison result", comp.compare(all, audio) > 0);
+		assertTrue("Invalid comparison result", comp.compare(allXml, MediaType.APPLICATION_XHTML_XML) > 0);
 
 		// qualifiers
 		assertTrue("Invalid comparison result", comp.compare(audio, audio07) < 0);