/* | |
* 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.Constants; | |
import com.alibaba.dubbo.rpc.Invoker; | |
import com.alibaba.dubbo.rpc.Invocation; | |
import com.alibaba.dubbo.rpc.cluster.LoadBalance; | |
/** | |
* AbstractLoadBalance | |
* | |
* @author william.liangf | |
*/ | |
public abstract class AbstractLoadBalance implements LoadBalance { | |
public <T> Invoker<T> select(List<Invoker<T>> invokers, Invocation invocation) { | |
if (invokers == null || invokers.size() == 0) | |
return null; | |
if (invokers.size() == 1) | |
return invokers.get(0); | |
return doSelect(invokers, invocation); | |
} | |
protected abstract <T> Invoker<T> doSelect(List<Invoker<T>> invokers, Invocation invocation); | |
protected int getWeight(Invoker<?> invoker, Invocation invocation) { | |
return invoker.getUrl().getMethodParameter(invocation.getMethodName(), Constants.WEIGHT_KEY, Constants.DEFAULT_WEIGHT); | |
} | |
} |