#1450 - Fix template variable cleanup for variables using regular expressions.

Switched to manual parsing of template variables as regular expressions can contain { and } characters which makes matching variables using these as delimiters impossible.

Related ticket: #1412.

src/main/java/org/springframework/hateoas/server/core/AnnotationMappingDiscoverer.java

@@ -25,7 +25,6 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
@@ -47,7 +46,6 @@ import org.springframework.web.bind.annotation.RequestMethod;
 public class AnnotationMappingDiscoverer implements MappingDiscoverer {
 
 	private static final Pattern MULTIPLE_SLASHES = Pattern.compile("/{2,}");
-	private static final Pattern TEMPLATE_VARIABLE_NAME = Pattern.compile("\\{(.*)\\}");
 
 	private final Class<? extends Annotation> annotationType;
 	private final String mappingAttributeName;
@@ -225,23 +223,44 @@ public class AnnotationMappingDiscoverer implements MappingDiscoverer {
 		return MULTIPLE_SLASHES.matcher(result.toString()).replaceAll("/");
 	}
 
-	private static String cleanupPart(String variable) {
+	private static String cleanupPart(String part) {
 
-		if (!variable.contains("{")) {
-			return variable;
+		StringBuilder builder = new StringBuilder();
+		int level = 0;
+		boolean inRegex = false;
+
+		for (int i = 0; i < part.length(); i++) {
+
+			char character = part.charAt(i);
+
+			if (character == '{') {
+
+				level++;
+
+				if (level == 1) {
+					builder.append(character);
+					continue;
+				}
+			}
+
+			if (level == 1 && character == ':') {
+				inRegex = true;
+			}
+
+			if (character == '}') {
+
+				level--;
+
+				if (level == 0) {
+					inRegex = false;
+				}
+			}
+
+			if (!inRegex) {
+				builder.append(character);
+			}
 		}
 
-		Matcher matcher = TEMPLATE_VARIABLE_NAME.matcher(variable);
-
-		if (!matcher.find()) {
-			return variable;
-		}
-
-		String rawName = matcher.group(1);
-		int colonIndex = rawName.indexOf(':');
-
-		return colonIndex < 0
-				? variable
-				: variable.replace(matcher.group(0), "{" + rawName.substring(0, colonIndex) + "}");
+		return builder.toString();
 	}
 }

src/test/java/org/springframework/hateoas/server/core/AnnotationMappingDiscovererUnitTest.java

@@ -171,6 +171,14 @@ class AnnotationMappingDiscovererUnitTest {
 		assertThat(discoverer.getConsumes(method)).isEmpty();
 	}
 
+	@Test // #1450
+	void extractsMultipleRegularExpressionVariablesCorrectly() throws Exception {
+
+		Method method = MyController.class.getMethod("multipleRegularExpressions");
+
+		assertThat(discoverer.getMapping(method)).isEqualTo("/type/spring-web/{symbolicName}-{version}{extension}");
+	}
+
 	@RequestMapping("/type")
 	interface MyController {
 
@@ -188,6 +196,9 @@ class AnnotationMappingDiscovererUnitTest {
 
 		@RequestMapping(path = "/path", consumes = "application/json")
 		void mappingWithConsumesClause();
+
+		@GetMapping("/spring-web/{symbolicName:[a-z-]+}-{version:\\d\\.\\d\\.\\d}{extension:\\.[a-z]+}")
+		void multipleRegularExpressions();
 	}
 
 	interface ControllerWithoutTypeLevelMapping {