SPR-6788: fixed compareTo() consistency with equals

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

@@ -27,6 +27,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.TreeSet;
 
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
@@ -311,9 +312,38 @@ public class MediaType implements Comparable<MediaType> {
 	 * @see #sortBySpecificity(List)
 	 */
 	public int compareTo(MediaType other) {
-		String s1 = this.toString();
-		String s2 = other.toString();
-		return s1.compareToIgnoreCase(s2);
+		int comp = this.type.compareToIgnoreCase(other.type);
+		if (comp != 0) {
+			return comp;
+		}
+		comp = this.subtype.compareToIgnoreCase(other.subtype);
+		if (comp != 0) {
+			return comp;
+		}
+		comp = this.parameters.size() - other.parameters.size();
+		if (comp != 0) {
+			return comp;
+		}
+		Iterator<String> thisAttributes = new TreeSet<String>(this.parameters.keySet()).iterator();
+		Iterator<String> otherAttributes = new TreeSet<String>(other.parameters.keySet()).iterator();
+		while (thisAttributes.hasNext()) {
+			String thisAttribute = thisAttributes.next();
+			String otherAttribute = otherAttributes.next();
+			comp = thisAttribute.compareToIgnoreCase(otherAttribute);
+			if (comp != 0) {
+				return comp;
+			}
+			String thisValue = this.parameters.get(thisAttribute);
+			String otherValue = other.parameters.get(otherAttribute);
+			if (otherValue == null) {
+				otherValue = "";
+			}
+			comp = thisValue.compareTo(otherValue);
+			if (comp != 0) {
+				return comp;
+			}
+		}
+		return 0;
 	}
 
 	@Override
@@ -348,7 +378,11 @@ public class MediaType implements Comparable<MediaType> {
 		builder.append(this.type);
 		builder.append('/');
 		builder.append(this.subtype);
-		for (Map.Entry<String, String> entry : this.parameters.entrySet()) {
+		appendTo(this.parameters, builder);
+	}
+
+	private static void appendTo(Map<String, String> map, StringBuilder builder) {
+		for (Map.Entry<String, String> entry : map.entrySet()) {
 			builder.append(';');
 			builder.append(entry.getKey());
 			builder.append('=');

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

@@ -177,6 +177,7 @@ public class MediaTypeTests {
 		MediaType audio = new MediaType("audio");
 		MediaType audioWave = new MediaType("audio", "wave");
 		MediaType audioBasicLevel = new MediaType("audio", "basic", Collections.singletonMap("level", "1"));
+		MediaType audioBasic07 = new MediaType("audio", "basic", 0.7);
 
 		// equal
 		assertEquals("Invalid comparison result", 0, audioBasic.compareTo(audioBasic));
@@ -189,6 +190,7 @@ public class MediaTypeTests {
 		expected.add(audio);
 		expected.add(audioBasic);
 		expected.add(audioBasicLevel);
+		expected.add(audioBasic07);
 		expected.add(audioWave);
 
 		List<MediaType> result = new ArrayList<MediaType>(expected);
@@ -199,10 +201,37 @@ public class MediaTypeTests {
 			Collections.sort(result);
 
 			for (int j = 0; j < result.size(); j++) {
-				assertSame("Invalid media type at " + j, expected.get(j), result.get(j));
+				assertSame("Invalid media type at " + j + ", run " + i, expected.get(j), result.get(j));
 			}
 		}
+	}
+
+	@Test
+	public void compareToConsistentWithEquals() {
+		MediaType m1 = MediaType.parseMediaType("text/html; q=0.7; charset=iso-8859-1");
+		MediaType m2 = MediaType.parseMediaType("text/html; charset=iso-8859-1; q=0.7");
 
+		assertEquals("Media types not equal", m1, m2);
+		assertEquals("compareTo() not consistent with equals", 0, m1.compareTo(m2));
+		assertEquals("compareTo() not consistent with equals", 0, m2.compareTo(m1));
+	}
+
+	@Test
+	public void compareToCaseSensitivity() {
+		MediaType m1 = new MediaType("audio", "basic");
+		MediaType m2 = new MediaType("Audio", "Basic");
+		assertEquals("Invalid comparison result", 0, m1.compareTo(m2));
+		assertEquals("Invalid comparison result", 0, m2.compareTo(m1));
+
+		m1 = new MediaType("audio", "basic", Collections.singletonMap("foo", "bar"));
+		m2 = new MediaType("audio", "basic", Collections.singletonMap("Foo", "bar"));
+		assertEquals("Invalid comparison result", 0, m1.compareTo(m2));
+		assertEquals("Invalid comparison result", 0, m2.compareTo(m1));
+
+		m1 = new MediaType("audio", "basic", Collections.singletonMap("foo", "bar"));
+		m2 = new MediaType("audio", "basic", Collections.singletonMap("foo", "Bar"));
+		assertTrue("Invalid comparison result", m1.compareTo(m2) != 0);
+		assertTrue("Invalid comparison result", m2.compareTo(m1) != 0);
 	}
 
 	@Test