org.apache.dubbo.rpc.cluster.Router Maven / Gradle / Ivy
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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 org.apache.dubbo.rpc.cluster;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.rpc.Invocation;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.RpcException;
import org.apache.dubbo.rpc.cluster.router.RouterResult;
import java.util.List;
/**
* Router. (SPI, Prototype, ThreadSafe)
*
* Routing
*
* @see org.apache.dubbo.rpc.cluster.Cluster#join(Directory, boolean)
* @see org.apache.dubbo.rpc.cluster.Directory#list(Invocation)
*/
public interface Router extends Comparable {
int DEFAULT_PRIORITY = Integer.MAX_VALUE;
/**
* Get the router url.
*
* @return url
*/
URL getUrl();
/**
* Filter invokers with current routing rule and only return the invokers that comply with the rule.
*
* @param invokers invoker list
* @param url refer url
* @param invocation invocation
* @return routed invokers
* @throws RpcException
*/
@Deprecated
default List> route(List> invokers, URL url, Invocation invocation) throws RpcException {
return null;
}
/**
* ** This method can return the state of whether routerChain needed to continue route. **
* Filter invokers with current routing rule and only return the invokers that comply with the rule.
*
* @param invokers invoker list
* @param url refer url
* @param invocation invocation
* @param needToPrintMessage whether to print router state. Such as `use router branch a`.
* @return state with route result
* @throws RpcException
*/
default RouterResult> route(List> invokers, URL url, Invocation invocation,
boolean needToPrintMessage) throws RpcException {
return new RouterResult<>(route(invokers, url, invocation));
}
/**
* Notify the router the invoker list. Invoker list may change from time to time. This method gives the router a
* chance to prepare before {@link Router#route(List, URL, Invocation)} gets called.
*
* @param invokers invoker list
* @param invoker's type
*/
default void notify(List> invokers) {
}
/**
* To decide whether this router need to execute every time an RPC comes or should only execute when addresses or
* rule change.
*
* @return true if the router need to execute every time.
*/
boolean isRuntime();
/**
* To decide whether this router should take effect when none of the invoker can match the router rule, which
* means the {@link #route(List, URL, Invocation)} would be empty. Most of time, most router implementation would
* default this value to false.
*
* @return true to execute if none of invokers matches the current router
*/
boolean isForce();
/**
* Router's priority, used to sort routers.
*
* @return router's priority
*/
int getPriority();
default void stop() {
//do nothing by default
}
@Override
default int compareTo(Router o) {
if (o == null) {
throw new IllegalArgumentException();
}
return Integer.compare(this.getPriority(), o.getPriority());
}
}