fix service list can not search by groupName only (#4308)

* fix service list can not search by groupName only

* fix service list can not search by groupName only

* fix checkStyle

* add ut for NamingUtils

api/src/main/java/com/alibaba/nacos/api/naming/utils/NamingUtils.java

@@ -27,6 +27,19 @@ import com.alibaba.nacos.api.utils.StringUtils;
  */
 public class NamingUtils {
     
+    /**
+     * Returns a combined string with serviceName and groupName. serviceName can not be nil.
+     *
+     * <p>In most cases, serviceName can not be nil. In other cases, for search or anything, See {@link
+     * com.alibaba.nacos.api.naming.utils.NamingUtils#getGroupedNameOptional(String, String)}
+     *
+     * <p>etc:
+     * <p>serviceName | groupName | result</p>
+     * <p>serviceA    | groupA    | groupA@@serviceA</p>
+     * <p>nil         | groupA    | threw IllegalArgumentException</p>
+     *
+     * @return 'groupName@@serviceName'
+     */
     public static String getGroupedName(final String serviceName, final String groupName) {
         if (StringUtils.isBlank(serviceName)) {
             throw new IllegalArgumentException("Param 'serviceName' is illegal, serviceName is blank");
@@ -73,4 +86,20 @@ public class NamingUtils {
                     "Param 'serviceName' is illegal, it should be format as 'groupName@@serviceName'");
         }
     }
+    
+    /**
+     * Returns a combined string with serviceName and groupName. Such as 'groupName@@serviceName'
+     * <p>This method works similar with {@link com.alibaba.nacos.api.naming.utils.NamingUtils#getGroupedName} But not verify any parameters.
+     *
+     * </p> etc:
+     * <p>serviceName | groupName | result</p>
+     * <p>serviceA    | groupA    | groupA@@serviceA</p>
+     * <p>nil         | groupA    | groupA@@</p>
+     * <p>nil         | nil       | @@</p>
+     *
+     * @return 'groupName@@serviceName'
+     */
+    public static String getGroupedNameOptional(final String serviceName, final String groupName) {
+        return groupName + Constants.SERVICE_INFO_SPLITER + serviceName;
+    }
 }

api/src/test/java/com/alibaba/nacos/api/naming/utils/NamingUtilsTest.java

@@ -0,0 +1,25 @@
+package com.alibaba.nacos.api.naming.utils;
+
+import com.alibaba.nacos.api.utils.StringUtils;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * @author mark4z
+ * @date 2020/11/25 13:35
+ */
+public class NamingUtilsTest{
+    
+    @Test
+    public void testGetGroupedNameOptional() {
+        String onlyGroupName = NamingUtils.getGroupedNameOptional(StringUtils.EMPTY, "groupA");
+        assertEquals(onlyGroupName, "groupA@@");
+        
+        String onlyServiceName =  NamingUtils.getGroupedNameOptional("serviceA" ,StringUtils.EMPTY);
+        assertEquals(onlyServiceName, "@@serviceA");
+        
+        String GroupNameAndServiceName = NamingUtils.getGroupedNameOptional("serviceA" ,"groupA");
+        assertEquals(GroupNameAndServiceName, "groupA@@serviceA");
+    }
+}

naming/src/main/java/com/alibaba/nacos/naming/controllers/CatalogController.java

@@ -187,7 +187,7 @@ public class CatalogController {
             @RequestParam(required = false) boolean hasIpCount) {
         
         String param = StringUtils.isBlank(serviceName) && StringUtils.isBlank(groupName) ? StringUtils.EMPTY
-                : NamingUtils.getGroupedName(serviceName, groupName);
+                : NamingUtils.getGroupedNameOptional(serviceName, groupName);
         
         if (withInstances) {
             List<ServiceDetailInfo> serviceDetailInfoList = new ArrayList<>();