/*
* JBoss, Home of Professional Open Source
* Copyright 2013, Red Hat, Inc. and/or its affiliates, and individual
* contributors by the @authors tag. See the copyright.txt in the
* distribution for a full listing of individual contributors.
*
* 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 org.jboss.as.quickstarts.servlet.async;
import javax.inject.Inject;
import javax.servlet.AsyncContext;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* <p>
* A simple asynchronous servlet taking advantage of features added in 3.0.
* </p>
*
* <p>
* The servlet is registered and mapped to /AsynchronousServlet using the {@link WebServlet} annotation. The
* {@link LongRunningService} is injected by CDI.
* </p>
*
* <p>
* It shows how to detach the execution of a long-running task from the request processing thread, so the thread is free to
* serve other client requests. The long-running tasks are executed using a dedicated thread pool and create the client response
* asynchronously using the {@link AsyncContext}.
* </p>
*
* <p>
* A long-running task in this context does not refer to a computation intensive task executed on the same machine but could for
* example be contacting a third-party service that has limited resources or only allows for a limited number of concurrent
* connections. Moving the calls to this service into a separate and smaller sized thread pool ensures that less threads will be
* busy interacting with the long-running service and that more requests can be served that do not depend on this service.
* </p>
*
* @author Christian Sadilek <csadilek@redhat.com>
*/
@SuppressWarnings("serial")
@WebServlet(value = "/AsynchronousServlet", asyncSupported = true)
public class AsynchronousServlet extends HttpServlet {
@Inject
private LongRunningService longRunningService;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
// Here the request is put in asynchronous mode
AsyncContext asyncContext = req.startAsync();
// This method will return immediately when invoked,
// the actual execution will run in a separate thread.
longRunningService.readData(asyncContext);
}
}