io.servicecomb.loadbalance.RuleClassNameExtentionsFactory.java Source code

Introduction

Here is the source code for io.servicecomb.loadbalance.RuleClassNameExtentionsFactory.java

Source

/*
 * 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.Collection;

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import com.google.common.collect.Lists;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RoundRobinRule;

/**
 * ?Rule?
 */
@Component
public class RuleClassNameExtentionsFactory implements ExtensionsFactory {
    private static final Logger LOGGER = LoggerFactory.getLogger(RuleClassNameExtentionsFactory.class);

    private static final Collection<String> ACCEPT_KEYS = Lists.newArrayList(Configuration.PROP_POLICY);

    // possible values
    //      "com.netflix.loadbalancer.RoundRobinRule"
    //      "com.netflix.loadbalancer.WeightedResponseTimeRule"
    //      "com.netflix.loadbalancer.RandomRule"
    //      "io.servicecomb.loadbalance.SessionStickinessRule"
    @Override
    public boolean isSupport(String key, String value) {
        return ACCEPT_KEYS.contains(key) && StringUtils.isNotEmpty(value);
    }

    @Override
    public IRule createLoadBalancerRule(String ruleName) {
        IRule rule;
        try {
            rule = (IRule) Class.forName(ruleName, true, Thread.currentThread().getContextClassLoader())
                    .newInstance();
        } catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
            LOGGER.warn("Loadbalance rule [{}] is incorrect, using default RoundRobinRule.", ruleName);
            rule = new RoundRobinRule();
        }
        return rule;
    }
}