add license

spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/metadata/repository/MetadataServiceInstanceSelector.java

@@ -1,3 +1,19 @@
+/*
+ * Copyright (C) 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.alibaba.cloud.dubbo.metadata.repository;
 
 import org.springframework.cloud.client.ServiceInstance;
@@ -8,8 +24,7 @@ import java.util.Optional;
 /**
  * metadata service instance selector
  *
- * @author liuxx
+ * @author <a href="mailto:liuxx-u@outlook.com">liuxx</a>
- * @date 2019/9/4
  */
 public interface MetadataServiceInstanceSelector {