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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html lang="en">
<head>
<title>The Servlet 3.0 Asynchronous Request Sample Application</title>
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<tr>
<td align="right" bgcolor="#587993" valign="top"> <font
color="#ffffff" size="-1"><b>Sun GlassFish Enterprise Server</b></font>
</td>
</tr>
</tbody>
</table>
<!---- Don't modify anything above this line, except for the title tag -------->
<p><a href="../../../../docs/list.html">Samples Main Page<br>
</a></p>
<h1>The Servlet 3.0 Asynchronous Sample Application</h1>
This is a simple Servlet 3.0 application using asychronous API.
<p><b>Servlet</b>
</p>
<p>The servlet is responsible for asynchronous request processing.
</p>
<blockquote>
<ul>
<li>In the <code>init</code> method, start a thread to read
message from the <code>messageQueue</code> and then process the
message for each <code>AsyncContext</code>
in
the queue as follows:
<p> <code>PrintWriter acWriter = ac.getResponse().getWriter();<br>
acWriter.println(cMessage);<br>
acWriter.flush();</code><br>
</p>
<p> The preceding code writes a message to each asynchronous
request
corresponding to <code>AsyncContext</code>. </p>
<p> </p>
</li>
<li>In <code>doGet</code>, set the timeout to ten minutes,
start asynchronous, and add <code>AsyncContext</code> to a queue as follows:
<p> <code>final AsyncContext ac = req.startAsync();<br>
ac.setTimeout(10 * 60 * 1000);<br>
queue.add(ac);</code><br>
</p>
<p> Registers <code>AsyncListener</code> with the <code>AsyncContext</code>. In this case, only clean up the <code>AsyncContext</code> from the queue. </p>
<p><code> ac.addListener(new AsyncListener() {<br>
public void onComplete(AsyncEvent event) throws
IOException {<br>
queue.remove(ac);<br>
}<br>
<br>
public void onTimeout(AsyncEvent event) throws
IOException {<br>
queue.remove(ac);<br>
}<br>
<br>
public void onError(AsyncEvent event) throws
IOException {<br>
queue.remove(ac);<br>
}<br>
<br>
public void onStartAsync(AsyncEvent event) throws
IOException {<br>
}<br>
});</code><br>
</p>
</li>
<li>In <code>doPost</code>, put a message to the
messageQueue. This message is picked up in the thread that starts in
the <code>init</code>
method. </li>
</ul>
</blockquote>
<b>Deployment Descriptor</b><br>
<br>
The good news is the deployment descriptor is no longer
required!<br>
<br>
<b>Sun GlassFish Enterprise Server Specific Deployment Configuration</b><br>
<br>
There is no need to define any Sun GlassFish Enterprise Server specific
deployment descrpitor (<code>sun-web.xml</code>) for this
example.
<br>
<h2>Building, Deploying, and Running the Application</h2>
<p>
</p>
<p>
Perform the following steps to build, deploy, and run the
application:
</p>
<ol>
<li> Set up your build environment and configure the application
server with which the build system has to work by following the <a
href="../../../../docs/UserREADME.html">
common build instructions.</a></li>
<li><code><i>app_dir</i></code> is the sample application base
directory: <code><i>samples_install_dir</i>/javaee6/web/servlet/async-request-war</code></li>
<li><code></code><code></code>Change directory to <code><i>app_dir.<br>
</i></code></li>
<li>Build, deploy, and run the sample application using the <code>all</code>
target.<code></code></li>
<p><code><span style="font-style: italic;">app_dir> </span>ant
all</code><br>
</p>
<p>You can replace the <code>ant all</code> command with the
following set of
commands:<br>
</p>
<p><code><span style="font-style: italic;">app_dir> </span>ant
default</code> compiles and packages the application </p>
<p><code><span style="font-style: italic;">app_dir> </span>ant
deploy</code> deploys it to application server </p>
<li>To run this chat application, you need two browsers, say
Browser A and Browser B.
<ul>
<li>In Browser A, open
http:<javaee.server.name>:<javaee.server.port>/async-request-war.
Repeat this step for Browser B also. </li>
<li>In Browser A, input user name, say "userA", in the text box.
Click the Login button. The following message is displayed in Browser A
and Browser B:
<p><code>System Message:<br>
userA has joined.</code> </p>
<p>Similarly, login as "userB" in Browser B. </p>
</li>
<li>Now, you are ready to chat. In Browser A,type "Hello", in
text box and click the Post Message button. You will see the following
message in both Browser A and Browser
B:
<p><code>userA:<br>
Hello</code> </p>
<p>Try the same step in Browser B also. </p>
</li>
</ul>
</li>
<li>Use the target <code>undeploy</code> to undeploy the application.
<p><code><span style="font-style: italic;">app_dir> </span>ant
undeploy</code> </p>
</li>
<li>Use the target <code>clean</code> to remove the temporary directories
like build and dist.
<p><code><span style="font-style: italic;">app_dir> </span>ant
clean</code> </p>
</li>
</ol>
<h2>Building, Deploying, and Running the Application in NetBeans IDE</h2>
<p>Perform the following steps to build, deploy, and run the application using NetBeans IDE:</p>
<ol>
<li> Refer to the <a href="../../../../docs/UserREADME.html"> common build instructions</a> for setting up NetBeans IDE and Sun GlassFish Enterprise Server.</li>
<li> In the NetBeans IDE, choose File → Open Project (Ctrl-Shift-O), navigate to the <code><i>samples_install_dir</i>/javaee6/web/servlet/</code> directory, select <code>async-request-war</code>, and click Open Project.</li>
<li> In the Projects tab, right click <code>async-request-war</code> and select Run to build, deploy, and run the project.</li>
</ol>
<h2>Troubleshooting</h2>
<p>If you have problems when running the application, refer the <a
href="../../../../docs/UserTroubleShooting.html">
troubleshooting document</a>.
</p>
<p><!--- Do not modify the rest of the document --></p>
<hr noshade="noshade" size="1"><!-- start copyright -->
<p class="copy"> Copyright © 2009 <a href="http://sun.com/">Sun
Microsystems, Inc.</a>
All rights reserved. </p>
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