org.apache.dubbo.rpc.AsyncContext 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;
/**
* AsyncContext works like {@see javax.servlet.AsyncContext} in the Servlet 3.0.
* An AsyncContext is stated by a call to {@link RpcContext#startAsync()}.
*
* The demo is {@see com.alibaba.dubbo.examples.async.AsyncConsumer}
* and {@see com.alibaba.dubbo.examples.async.AsyncProvider}
*/
public interface AsyncContext {
/**
* write value and complete the async context.
*
* @param value invoke result
*/
void write(Object value);
/**
* @return true if the async context is started
*/
boolean isAsyncStarted();
/**
* change the context state to stop
*/
boolean stop();
/**
* change the context state to start
*/
void start();
/**
* Signal RpcContext switch.
* Use this method to switch RpcContext from a Dubbo thread to a new thread created by the user.
*
* Note that you should use it in a new thread like this:
*
* public class AsyncServiceImpl implements AsyncService {
* public String sayHello(String name) {
* final AsyncContext asyncContext = RpcContext.startAsync();
* new Thread(() -> {
*
* // right place to use this method
* asyncContext.signalContextSwitch();
*
* try {
* Thread.sleep(500);
* } catch (InterruptedException e) {
* e.printStackTrace();
* }
* asyncContext.write("Hello " + name + ", response from provider.");
* }).start();
* return null;
* }
* }
*
*/
void signalContextSwitch();
}