Update MediaType's includes method

An additional update (after the last commit) of the "includes" and
"isCompatibleWith" methods of MediaType to accomodate wildcards
in media types with a suffix.

Issue: SPR-9841

Author: rstoyanchev

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

@@ -482,19 +482,27 @@ public boolean includes(MediaType other) {
 			return true;
 		}
 		else if (this.type.equals(other.type)) {
-			if (this.subtype.equals(other.subtype) || this.isWildcardSubtype()) {
+			if (this.subtype.equals(other.subtype)) {
 				return true;
 			}
-			// application/*+xml includes application/soap+xml
-			int thisPlusIdx = this.subtype.indexOf('+');
-			int otherPlusIdx = other.subtype.indexOf('+');
-			if (thisPlusIdx != -1 && otherPlusIdx != -1) {
-				String thisSubtypeNoSuffix = this.subtype.substring(0, thisPlusIdx);
-				String thisSubtypeSuffix = this.subtype.substring(thisPlusIdx + 1);
-				String otherSubtypeSuffix = other.subtype.substring(otherPlusIdx + 1);
-				if (thisSubtypeSuffix.equals(otherSubtypeSuffix) && WILDCARD_TYPE.equals(thisSubtypeNoSuffix)) {
+			if (this.isWildcardSubtype()) {
+				// wildcard with suffix, e.g. application/*+xml
+				int thisPlusIdx = this.subtype.indexOf('+');
+				if (thisPlusIdx == -1) {
 					return true;
 				}
+				else {
+					// application/*+xml includes application/soap+xml
+					int otherPlusIdx = other.subtype.indexOf('+');
+					if (otherPlusIdx != -1) {
+						String thisSubtypeNoSuffix = this.subtype.substring(0, thisPlusIdx);
+						String thisSubtypeSuffix = this.subtype.substring(thisPlusIdx + 1);
+						String otherSubtypeSuffix = other.subtype.substring(otherPlusIdx + 1);
+						if (thisSubtypeSuffix.equals(otherSubtypeSuffix) && WILDCARD_TYPE.equals(thisSubtypeNoSuffix)) {
+							return true;
+						}
+					}
+				}
 			}
 		}
 		return false;
@@ -515,23 +523,30 @@ public boolean isCompatibleWith(MediaType other) {
 			return true;
 		}
 		else if (this.type.equals(other.type)) {
-			if (this.subtype.equals(other.subtype) || this.isWildcardSubtype() || other.isWildcardSubtype()) {
+			if (this.subtype.equals(other.subtype)) {
 				return true;
 			}
-			// application/*+xml is compatible with application/soap+xml, and vice-versa
-			int thisPlusIdx = this.subtype.indexOf('+');
-			int otherPlusIdx = other.subtype.indexOf('+');
-			if (thisPlusIdx != -1 && otherPlusIdx != -1) {
-				String thisSubtypeNoSuffix = this.subtype.substring(0, thisPlusIdx);
-				String otherSubtypeNoSuffix = other.subtype.substring(0, otherPlusIdx);
-
-				String thisSubtypeSuffix = this.subtype.substring(thisPlusIdx + 1);
-				String otherSubtypeSuffix = other.subtype.substring(otherPlusIdx + 1);
-
-				if (thisSubtypeSuffix.equals(otherSubtypeSuffix) &&
-						(WILDCARD_TYPE.equals(thisSubtypeNoSuffix) || WILDCARD_TYPE.equals(otherSubtypeNoSuffix))) {
+			// wildcard with suffix? e.g. application/*+xml
+			if (this.isWildcardSubtype() || other.isWildcardSubtype()) {
+
+				int thisPlusIdx = this.subtype.indexOf('+');
+				int otherPlusIdx = other.subtype.indexOf('+');
+
+				if (thisPlusIdx == -1 && otherPlusIdx == -1) {
 					return true;
 				}
+				else if (thisPlusIdx != -1 && otherPlusIdx != -1) {
+					String thisSubtypeNoSuffix = this.subtype.substring(0, thisPlusIdx);
+					String otherSubtypeNoSuffix = other.subtype.substring(0, otherPlusIdx);
+
+					String thisSubtypeSuffix = this.subtype.substring(thisPlusIdx + 1);
+					String otherSubtypeSuffix = other.subtype.substring(otherPlusIdx + 1);
+
+					if (thisSubtypeSuffix.equals(otherSubtypeSuffix) &&
+							(WILDCARD_TYPE.equals(thisSubtypeNoSuffix) || WILDCARD_TYPE.equals(otherSubtypeNoSuffix))) {
+						return true;
+					}
+				}
 			}
 		}
 		return false;

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

@@ -59,6 +59,8 @@ public void includes() throws Exception {
 
 		assertTrue(applicationWildcardXml.includes(applicationSoapXml));
 		assertFalse(applicationSoapXml.includes(applicationWildcardXml));
+
+		assertFalse(applicationWildcardXml.includes(MediaType.APPLICATION_JSON));
 	}
 
 	@Test
@@ -84,6 +86,8 @@ public void isCompatible() throws Exception {
 
 		assertTrue(applicationWildcardXml.isCompatibleWith(applicationSoapXml));
 		assertTrue(applicationSoapXml.isCompatibleWith(applicationWildcardXml));
+
+		assertFalse(applicationWildcardXml.isCompatibleWith(MediaType.APPLICATION_JSON));
 	}
 
 	@Test