io.servicecomb.loadbalance.LoadBalancer Maven / Gradle / Ivy

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/*
 * Copyright 2017 Huawei Technologies Co., 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 io.servicecomb.loadbalance;

import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import com.netflix.loadbalancer.AbstractLoadBalancer;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.LoadBalancerStats;
import com.netflix.loadbalancer.Server;
import com.netflix.loadbalancer.ServerListFilter;

/**
 * 实现不包含服务器状态监测的负载均衡器。（这些职责在注册中心客户端实现）
 *
 */
public class LoadBalancer extends AbstractLoadBalancer {
    private CseServerList serverList;

    private IRule rule;

    private LoadBalancerStats lbStats;

    // 以filter类名为Key
    private Map> filters;

    private Object lock = new Object();

    public LoadBalancer(CseServerList serverList, IRule rule) {
        this.serverList = serverList;
        this.rule = rule;
        this.rule.setLoadBalancer(this);
        this.lbStats = new LoadBalancerStats(null);
        this.filters = new ConcurrentHashMap<>();
    }

    @Override
    public void addServers(List newServers) {
        throw new UnsupportedOperationException("Not implemented.");
    }

    @Override
    public Server chooseServer(Object key) {
        return rule.choose(key);
    }

    @Override
    public void markServerDown(Server server) {
        throw new UnsupportedOperationException("Not implemented.");
    }

    @Override
    public List getServerList(boolean availableOnly) {
        return getAllServers();
    }

    @Override
    public List getReachableServers() {
        return getAllServers();
    }

    @Override
    public List getAllServers() {
        List servers = serverList.getInitialListOfServers();
        for (ServerListFilter filter : filters.values()) {
            servers = filter.getFilteredListOfServers(servers);
        }
        return servers;
    }

    @Override
    public List getServerList(ServerGroup serverGroup) {
        throw new UnsupportedOperationException("Not implemented.");
    }

    @Override
    public LoadBalancerStats getLoadBalancerStats() {
        return lbStats;
    }

    public boolean containsFilter(String name) {
        return filters.get(name) != null;
    }

    public void removeFilter(String name) {
        if (filters.get(name) != null) {
            synchronized (lock) {
                if (filters.get(name) != null) {
                    filters.remove(name);
                }
            }
        }
    }

    public void putFilter(String name, ServerListFilter filter) {
        if (filters.get(name) == null) {
            synchronized (lock) {
                if (filters.get(name) == null) {
                    filters.put(name, filter);
                }
            }
        }
    }

    public int getFilterSize() {
        return filters.size();
    }
}