/*
* Copyright 1999-2011 Alibaba Group.
*
* 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.dubbo.rpc.cluster.loadbalance;
import java.util.List;
import com.alibaba.dubbo.common.Adaptive;
import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.ExtensionLoader;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.cluster.LoadBalance;
/**
* LoadBalanceAdptive
*
* @author ding.lid
* @author william.liangf
*/
@Adaptive
public class LoadBalanceAdptive implements LoadBalance {
public <T> Invoker<T> select(List<Invoker<T>> invokers, Invocation invocation) throws RpcException {
if (invokers == null || invokers.size() == 0) {
return null;
}
URL url = invokers.get(0).getUrl();
String method = invocation.getMethodName();
String name;
if (method == null || method.length() == 0) {
name = url.getParameter(Constants.LOADBALANCE_KEY, Constants.DEFAULT_LOADBALANCE);
} else {
name = url.getMethodParameter(method, Constants.LOADBALANCE_KEY, Constants.DEFAULT_LOADBALANCE);
}
LoadBalance loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(name);
return loadbalance.select(invokers, invocation);
}
}