Functional PathPattern comparator

spring-web/src/main/java/org/springframework/web/util/pattern/PathPattern.java

@@ -692,44 +692,22 @@ public class PathPattern implements Comparable<PathPattern> {
 	}
 
 
-	public static final Comparator<PathPattern> SPECIFICITY_COMPARATOR = (p1, p2) -> {
+	/**
-		// Same object or null == null?
+	 * Comparator that sorts patterns by specificity as follows:
-		if (p1 == p2) {
+	 * <ol>
-			return 0;
+	 * <li>Null instances are last.
-		}
+	 * <li>Catch-all patterns are last.
-
+	 * <li>If both patterns are catch-all, consider the length (longer wins).
-		// null is sorted last
+	 * <li>Compare wildcard and captured variable count (lower wins).
-		if (p2 == null) {
+	 * <li>Consider length (longer wins)
-			return -1;
+	 * </ol>
-		}
+	 */
-
+	public static final Comparator<PathPattern> SPECIFICITY_COMPARATOR =
-		// catchall patterns are sorted last. If both catchall then the
+			Comparator.nullsLast(
-		// length is considered
+					Comparator.<PathPattern>
-		if (p1.isCatchAll()) {
+							comparingInt(p -> p.isCatchAll() ? 1 : 0)
-			if (p2.isCatchAll()) {
+							.thenComparingInt(p -> p.isCatchAll() ? -1 * p.getNormalizedLength() : 0)
-				int lenDifference = p1.getNormalizedLength() - p2.getNormalizedLength();
+							.thenComparing(PathPattern::getScore)
-				if (lenDifference != 0) {
+							.thenComparingInt(p -> -1 * p.getNormalizedLength())
-					return (lenDifference < 0) ? +1 : -1;
+			);
-				}
-			}
-			else {
-				return +1;
-			}
-		}
-		else if (p2.isCatchAll()) {
-			return -1;
-		}
-
-		// This will sort such that if they differ in terms of wildcards or
-		// captured variable counts, the one with the most will be sorted last
-		int score = p1.getScore() - p2.getScore();
-		if (score != 0) {
-			return (score < 0) ? -1 : +1;
-		}
-
-		// longer is better
-		int lenDifference = p1.getNormalizedLength() - p2.getNormalizedLength();
-		return Integer.compare(0, lenDifference);
-	};
-
 }

spring-web/src/test/java/org/springframework/web/util/pattern/PathPatternTests.java

@@ -967,10 +967,10 @@ public class PathPatternTests {
 	}
 
 	@Test
-	public void patternCompareToNull() {
+	public void patternCompareWithNull() {
-		PathPatternParser p = new PathPatternParser();
+		assertTrue(PathPattern.SPECIFICITY_COMPARATOR.compare(null, null) == 0);
-		PathPattern pp = p.parse("/abc");
+		assertTrue(PathPattern.SPECIFICITY_COMPARATOR.compare(parse("/abc"), null) < 0);
-		assertEquals(-1, pp.compareTo(null));
+		assertTrue(PathPattern.SPECIFICITY_COMPARATOR.compare(null, parse("/abc")) > 0);
 	}
 
 	@Test