com.alibaba.nacos.naming.selector.Selector Maven / Gradle / Ivy
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* 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
*
* http://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.nacos.naming.selector;
import com.alibaba.nacos.naming.core.Instance;
import java.util.List;
/**
* Selector defines a rule for load-balance for service discovery.
*
* Every service in Nacos can apply an existing selector and uses it to give the consumer
* a subset of selected providers.
*
* This selector itself does not implement any specific behavior of load-balance, every
* real life selector should extend this class and implement the select method.
*
* Every extended selector should also register its type to class SelectorType so Nacos
* recognizes it and can correctly create this type of selector.
*
* @author nkorange
* @see com.alibaba.nacos.api.selector.SelectorType
* @see SelectorJsonAdapter
* @since 0.7.0
*/
public interface Selector {
/**
* Get the type of this selector
*
* @return type of selector
*/
String getType();
/**
* Select qualified instances from providers
*
* @param consumer consumer address
* @param providers candidate provider addresses
* @return selected provider addresses
*/
List select(String consumer, List providers);
}