MimeType.compareTo uses case-insensitive Charset (analogous to equals)

Issue: SPR-16458

spring-core/src/main/java/org/springframework/util/MimeType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -319,7 +319,7 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 				return true;
 			}
 			if (this.isWildcardSubtype()) {
-				// wildcard with suffix, e.g. application/*+xml
+				// Wildcard with suffix, e.g. application/*+xml
 				int thisPlusIdx = getSubtype().lastIndexOf('+');
 				if (thisPlusIdx == -1) {
 					return true;
@@ -361,22 +361,18 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 			if (getSubtype().equals(other.getSubtype())) {
 				return true;
 			}
-			// wildcard with suffix? e.g. application/*+xml
+			// Wildcard with suffix? e.g. application/*+xml
 			if (this.isWildcardSubtype() || other.isWildcardSubtype()) {
-
 				int thisPlusIdx = getSubtype().lastIndexOf('+');
 				int otherPlusIdx = other.getSubtype().lastIndexOf('+');
-
 				if (thisPlusIdx == -1 && otherPlusIdx == -1) {
 					return true;
 				}
 				else if (thisPlusIdx != -1 && otherPlusIdx != -1) {
 					String thisSubtypeNoSuffix = getSubtype().substring(0, thisPlusIdx);
 					String otherSubtypeNoSuffix = other.getSubtype().substring(0, otherPlusIdx);
-
 					String thisSubtypeSuffix = getSubtype().substring(thisPlusIdx + 1);
 					String otherSubtypeSuffix = other.getSubtype().substring(otherPlusIdx + 1);
-
 					if (thisSubtypeSuffix.equals(otherSubtypeSuffix) &&
 							(WILDCARD_TYPE.equals(thisSubtypeNoSuffix) || WILDCARD_TYPE.equals(otherSubtypeNoSuffix))) {
 						return true;
@@ -417,7 +413,6 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 			if (!other.parameters.containsKey(key)) {
 				return false;
 			}
-
 			if (PARAM_CHARSET.equals(key)) {
 				if (!ObjectUtils.nullSafeEquals(getCharset(), other.getCharset())) {
 					return false;
@@ -481,12 +476,14 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 		if (comp != 0) {
 			return comp;
 		}
+
 		TreeSet<String> thisAttributes = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
 		thisAttributes.addAll(getParameters().keySet());
 		TreeSet<String> otherAttributes = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
 		otherAttributes.addAll(other.getParameters().keySet());
 		Iterator<String> thisAttributesIterator = thisAttributes.iterator();
 		Iterator<String> otherAttributesIterator = otherAttributes.iterator();
+
 		while (thisAttributesIterator.hasNext()) {
 			String thisAttribute = thisAttributesIterator.next();
 			String otherAttribute = otherAttributesIterator.next();
@@ -494,6 +491,23 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 			if (comp != 0) {
 				return comp;
 			}
+			if (PARAM_CHARSET.equals(thisAttribute)) {
+				Charset thisCharset = getCharset();
+				Charset otherCharset = other.getCharset();
+				if (thisCharset != otherCharset) {
+					if (thisCharset == null) {
+						return -1;
+					}
+					if (otherCharset == null) {
+						return 1;
+					}
+					comp = thisCharset.compareTo(otherCharset);
+					if (comp != 0) {
+						return comp;
+					}
+				}
+			}
+			else {
 				String thisValue = getParameters().get(thisAttribute);
 				String otherValue = other.getParameters().get(otherAttribute);
 				if (otherValue == null) {
@@ -504,6 +518,8 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 					return comp;
 				}
 			}
+		}
+
 		return 0;
 	}
 
@@ -557,7 +573,7 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 		protected int compareParameters(T mimeType1, T mimeType2) {
 			int paramsSize1 = mimeType1.getParameters().size();
 			int paramsSize2 = mimeType2.getParameters().size();
-			return (paramsSize2 < paramsSize1 ? -1 : (paramsSize2 == paramsSize1 ? 0 : 1)); // audio/basic;level=1 < audio/basic
+			return Integer.compare(paramsSize2, paramsSize1);  // audio/basic;level=1 < audio/basic
 		}
 	}
 

spring-core/src/test/java/org/springframework/util/MimeTypeTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -27,12 +27,8 @@ import org.junit.Test;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
 
-import static java.util.Collections.singletonMap;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertTrue;
+import static java.util.Collections.*;
+import static org.junit.Assert.*;
 
 /**
  * Unit tests for {@link MimeType}.
@@ -335,6 +331,8 @@ public class MimeTypeTests {
 		MimeType m2 = new MimeType("text", "plain", singletonMap("charset", "utf-8"));
 		assertEquals(m1, m2);
 		assertEquals(m2, m1);
+		assertEquals(0, m1.compareTo(m2));
+		assertEquals(0, m2.compareTo(m1));
 	}
 
 }