/
TagRouter.java
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/
TagRouter.java
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.router.tag;
import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.StringUtils;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.RpcContext;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.cluster.Router;
import java.util.ArrayList;
import java.util.List;
/**
* TagRouter
*/
public class TagRouter implements Router {
private static final Logger logger = LoggerFactory.getLogger(TagRouter.class);
private static final int DEFAULT_PRIORITY = 100;
private static final URL ROUTER_URL = new URL("tag", Constants.ANYHOST_VALUE, 0, Constants.ANY_VALUE).addParameters(Constants.RUNTIME_KEY, "true");
private URL url;
private int priority;
public TagRouter(URL url) {
this.url = url;
this.priority = url.getParameter(Constants.PRIORITY_KEY, DEFAULT_PRIORITY);
}
public TagRouter() {
this.url = ROUTER_URL;
this.priority = url.getParameter(Constants.PRIORITY_KEY, DEFAULT_PRIORITY);
}
@Override
public URL getUrl() {
return url;
}
@Override
public <T> List<Invoker<T>> route(List<Invoker<T>> invokers, URL url, Invocation invocation) throws RpcException {
// filter
List<Invoker<T>> result = new ArrayList<Invoker<T>>();
try {
// Dynamic param
String tag = RpcContext.getContext().getAttachment(Constants.REQUEST_TAG_KEY);
// Tag request
if (!StringUtils.isEmpty(tag)) {
// Select tag invokers first
for (Invoker<T> invoker : invokers) {
if (tag.equals(invoker.getUrl().getParameter(Constants.TAG_KEY))) {
result.add(invoker);
}
}
}
// If Constants.REQUEST_TAG_KEY unspecified or no invoker be selected, downgrade to normal invokers
if (result.isEmpty()) {
for (Invoker<T> invoker : invokers) {
if (StringUtils.isEmpty(invoker.getUrl().getParameter(Constants.TAG_KEY))) {
result.add(invoker);
}
}
}
return result;
} catch (Exception e) {
logger.error("Route by tag error,return all invokers.", e);
}
// Downgrade to all invokers
return invokers;
}
@Override
public int compareTo(Router o) {
if (o == null || o.getClass() != TagRouter.class) {
return 0;
}
TagRouter c = (TagRouter) o;
return this.priority == c.priority ? 0 : (this.priority > c.priority ? 1 : -1);
}
}