com.huawei.discovery.service.lb.rule.AbstractLoadbalancer Maven / Gradle / Ivy
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/*
* Copyright (C) 2022-2022 Huawei Technologies Co., Ltd. All rights reserved.
*
* 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.huawei.discovery.service.lb.rule;
import com.huawei.discovery.entity.ServiceInstance;
import java.util.List;
import java.util.Optional;
/**
* 抽象层
*
* @author zhouss
* @since 2022-09-26
*/
public abstract class AbstractLoadbalancer implements Loadbalancer {
@Override
public Optional choose(String serviceName, List instances) {
if (instances == null || instances.isEmpty()) {
return Optional.empty();
}
if (instances.size() == 1) {
return Optional.ofNullable(instances.get(0));
}
return Optional.ofNullable(doChoose(serviceName, instances));
}
/**
* 选择实例
*
* @param serviceName 服务名
* @param instances 实例列表
* @return 选择后的实例
*/
protected abstract ServiceInstance doChoose(String serviceName, List instances);
/**
* 负载均衡类型
*
* @return lbType
*/
public abstract String lbType();
}