Dedicated specificity comparator in PathPattern

The PathPattern compareTo method is now consistent with equals when
two patterns are of the same specificity but otherwise different.

Separately PathPattern now exposes a Comparator by specificity that
offers the current functionality of compareTo. This can be used for
actual sorting where we only care about specificity.

spring-webflux/src/main/java/org/springframework/web/reactive/handler/AbstractUrlHandlerMapping.java

@@ -118,7 +118,8 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 
 		return this.handlerMap.entrySet().stream()
 				.filter(entry -> entry.getKey().matches(lookupPath))
-				.sorted(Comparator.comparing(Map.Entry::getKey))
+				.sorted((entry1, entry2) ->
+						PathPattern.SPECIFICITY_COMPARATOR.compare(entry1.getKey(), entry2.getKey()))
 				.findFirst()
 				.map(entry -> {
 					PathPattern pattern = entry.getKey();

spring-webflux/src/main/java/org/springframework/web/reactive/resource/ResourceUrlProvider.java

@@ -166,7 +166,8 @@ public class ResourceUrlProvider implements ApplicationListener<ContextRefreshed
 	private Mono<String> resolveResourceUrl(PathContainer lookupPath) {
 		return this.handlerMap.entrySet().stream()
 				.filter(entry -> entry.getKey().matches(lookupPath))
-				.sorted(Comparator.comparing(Map.Entry::getKey))
+				.sorted((entry1, entry2) ->
+						PathPattern.SPECIFICITY_COMPARATOR.compare(entry1.getKey(), entry2.getKey()))
 				.findFirst()
 				.map(entry -> {
 					PathContainer path = entry.getKey().extractPathWithinPattern(lookupPath);

spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/PatternsRequestCondition.java

@@ -19,7 +19,6 @@ package org.springframework.web.reactive.result.condition;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
@@ -61,7 +60,7 @@ public final class PatternsRequestCondition extends AbstractRequestCondition<Pat
 	}
 
 	private static SortedSet<PathPattern> toSortedSet(Collection<PathPattern> patterns) {
-		TreeSet<PathPattern> sorted = new TreeSet<>(getPatternComparator());
+		TreeSet<PathPattern> sorted = new TreeSet<>();
 		sorted.addAll(patterns);
 		return sorted;
 	}
@@ -70,13 +69,6 @@ public final class PatternsRequestCondition extends AbstractRequestCondition<Pat
 		this.patterns = patterns;
 	}
 
-	private static Comparator<PathPattern> getPatternComparator() {
-		return (p1, p2) -> {
-			int index = p1.compareTo(p2);
-			return (index != 0 ? index : p1.getPatternString().compareTo(p2.getPatternString()));
-		};
-	}
-
 	public Set<PathPattern> getPatterns() {
 		return this.patterns;
 	}
@@ -170,7 +162,7 @@ public final class PatternsRequestCondition extends AbstractRequestCondition<Pat
 		Iterator<PathPattern> iterator = this.patterns.iterator();
 		Iterator<PathPattern> iteratorOther = other.getPatterns().iterator();
 		while (iterator.hasNext() && iteratorOther.hasNext()) {
-			int result = iterator.next().compareTo(iteratorOther.next());
+			int result = PathPattern.SPECIFICITY_COMPARATOR.compare(iterator.next(), iteratorOther.next());
 			if (result != 0) {
 				return result;
 			}

spring-webflux/src/test/java/org/springframework/web/reactive/result/condition/PatternsRequestConditionTests.java

@@ -137,7 +137,7 @@ public class PatternsRequestConditionTests {
 	}
 
 	@Test
-	public void compareEqualPatterns() throws Exception {
+	public void compareToConsistentWithEquals() throws Exception {
 		PatternsRequestCondition c1 = createPatternsCondition("/foo*");
 		PatternsRequestCondition c2 = createPatternsCondition("/foo*");
 
@@ -155,10 +155,17 @@ public class PatternsRequestConditionTests {
 
 	@Test
 	public void comparePatternSpecificity() throws Exception {
+		ServerWebExchange exchange = get("/foo").toExchange();
+
 		PatternsRequestCondition c1 = createPatternsCondition("/fo*");
 		PatternsRequestCondition c2 = createPatternsCondition("/foo");
 
-		assertEquals(1, c1.compareTo(c2, get("/foo").toExchange()));
+		assertEquals(1, c1.compareTo(c2, exchange));
+
+		c1 = createPatternsCondition("/fo*");
+		c2 = createPatternsCondition("/*oo");
+
+		assertEquals("Patterns are equally specific even if not the same", 0, c1.compareTo(c2, exchange));
 	}
 
 	@Test

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/HandlerMethodMappingTests.java

@@ -160,7 +160,7 @@ public class HandlerMethodMappingTests {
 
 		@Override
 		protected Comparator<String> getMappingComparator(ServerWebExchange exchange) {
-			return Comparator.comparing(o -> parser.parse(o));
+			return (o1, o2) -> PathPattern.SPECIFICITY_COMPARATOR.compare(parser.parse(o1), parser.parse(o2));
 		}
 
 	}