Fix the bug that legacy API matchers in ScGatewayApiMatcherManager were not removed (#2436)

* Fix the bug that legacy API matchers in SC gateway adapter GatewayApiMatcherManager were not removed after the API group has been removed

Author: su-yh

sentinel-adapter/sentinel-spring-cloud-gateway-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/gateway/sc/api/GatewayApiMatcherManager.java

@@ -15,23 +15,23 @@
  */
 package com.alibaba.csp.sentinel.adapter.gateway.sc.api;
 
+import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiDefinition;
+import com.alibaba.csp.sentinel.adapter.gateway.sc.api.matcher.WebExchangeApiMatcher;
+
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 
-import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiDefinition;
-import com.alibaba.csp.sentinel.adapter.gateway.sc.api.matcher.WebExchangeApiMatcher;
-
 /**
  * @author Eric Zhao
  * @since 1.6.0
  */
 public final class GatewayApiMatcherManager {
 
-    private static final Map<String, WebExchangeApiMatcher> API_MATCHER_MAP = new ConcurrentHashMap<>();
+    private static volatile Map<String, WebExchangeApiMatcher> API_MATCHER_MAP = new HashMap<>();
 
     public static Map<String, WebExchangeApiMatcher> getApiMatcherMap() {
         return Collections.unmodifiableMap(API_MATCHER_MAP);
@@ -50,15 +50,12 @@ public static Set<ApiDefinition> getApiDefinitionSet() {
     }
 
     static synchronized void loadApiDefinitions(/*@Valid*/ Set<ApiDefinition> definitions) {
-        if (definitions == null || definitions.isEmpty()) {
-            API_MATCHER_MAP.clear();
-            return;
+        Map<String, WebExchangeApiMatcher> apiMatcherMap = new HashMap<>();
+        for (ApiDefinition definition : definitions) {
+            apiMatcherMap.put(definition.getApiName(), new WebExchangeApiMatcher(definition));
         }
-        definitions.forEach(GatewayApiMatcherManager::addApiDefinition);
-    }
 
-    static void addApiDefinition(ApiDefinition definition) {
-        API_MATCHER_MAP.put(definition.getApiName(), new WebExchangeApiMatcher(definition));
+        API_MATCHER_MAP = apiMatcherMap;
     }
 
     private GatewayApiMatcherManager() {}