/*
 * 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.csp.sentinel.traffic;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

/**
 * @author panxiaojun233
 */
public class RandomLoadBalancer extends AbstractLoadBalancer {

    @Override
    protected Instance doSelect(List<Instance> instances, TrafficContext trafficContext) {
        // Number of invokers
        int length = instances.size();
        // If all invokers have the same weight value or totalWeight=0, return evenly.
        return instances.get(ThreadLocalRandom.current().nextInt(length));
    }
}
