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			104 lines
		
	
	
		
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								<html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Apache Tomcat Architecture - Architecture Overview</title><meta name="author" value="Yoav Shapira"><meta name="email" value="yoavs@apache.org"></head><body bgcolor="#ffffff" text="#000000" link="#525D76" alink="#525D76" vlink="#525D76"><table border="0" width="100%" cellspacing="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img src="../../images/tomcat.gif" align="right" alt="
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								      The Apache Tomcat Servlet/JSP Container
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								    " border="0"></a></td><td><font face="arial,helvetica,sanserif"><h1>Apache Tomcat 6.0</h1></font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="../../images/asf-logo.gif" align="right" alt="Apache Logo" border="0"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><tr><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left"><table border="0" width="100%" cellspacing="4"><tr><td align="left" valign="top"><h1>Apache Tomcat Architecture</h1><h2>Architecture Overview</h2></td><td align="right" valign="top" nowrap="true"><img src="../../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Overview"><strong>Overview</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								This page provides an overview of the Tomcat server architecture.
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								</p>
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								</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Terms"><strong>Terms</strong></a></font></td></tr><tr><td><blockquote>
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								<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Server"><strong>Server</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								In the Tomcat world, a
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								<a href="../../config/server.html">Server</a> represents the whole container.
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								Tomcat provides a default implementation of the 
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								<a href="../../catalina/docs/api/org/apache/catalina/Server.html">Server interface.</a>,
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								and this is rarely customized by users.
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								</p>
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								</blockquote></td></tr></table>
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								<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Service"><strong>Service</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								A <a href="../../config/service.html">Service</a> is an intermediate component
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								which lives inside a Server and ties one or more Connectors to exactly one
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								Engine.  The Service element is rarely customized by users, as the default
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								implementation is simple and sufficient:
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								<a href="../../catalina/docs/api/org/apache/catalina/Service.html">Service interface</a>.
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								</p>
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								</blockquote></td></tr></table>
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								<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Engine"><strong>Engine</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								An
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								<a href="../../config/engine.html">Engine</a> represents request processing
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								pipeline for a specific Service.  As a Service may have multiple Connectors,
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								the Engine received and processes all requests from these connectors, handing
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								the response back to the appropriate connector for transmission to the client.
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								The <a href="../../catalina/docs/api/org/apache/catalina/Engine.html">Engine interface</a>
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								may be implemented to supply custom Engines, though this is uncommon.
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								</p>
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								<p>
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								Note that the Engine may be used for Tomcat server clustering via the
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								jvmRoute parameter.  Read the Clustering documentation for more information.
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								</p>
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								</blockquote></td></tr></table>
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								<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Host"><strong>Host</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								A <a href="../../config/host.html">Host</a> is an association of a network name,
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								e.g. www.yourcompany.com, to the Tomcat server.  An Engine may contain
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								multiple hosts, and the Host element also supports network aliases such as
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								yourcompany.com and abc.yourcompany.com.  Users rarely create custom
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								<a href="../../catalina/docs/api/org/apache/catalina/Host.html">Hosts</a>
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								because the 
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								<a href="../../catalina/docs/api/org/apache/catalina/core/StandardHost.html">StandardHost
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								implementation</a> provides significant additional functionality.
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								</p>
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								</blockquote></td></tr></table>
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								<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Connector"><strong>Connector</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								A Connector handles communications with the client.  There are multiple
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								connectors available with Tomcat, all of which implement the 
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								<a href="../../catalina/docs/api/org/apache/catalina/Connector.html">Connector
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								interface.</a>  These include the
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								<a href="../../config/coyote.html">Coyote connector</a> which is used for
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								most HTTP traffic, especially when running Tomcat as a standalone server, 
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								and the <a href="../../config/jk2.html">JK2 connector</a> which implements
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								the AJP procotol used when connecting Tomcat to an Apache HTTPD server.
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								Creating a customized connector is a significant effort.
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								</p>
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								</blockquote></td></tr></table>
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								<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Context"><strong>Context</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								A
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								<a href="../../config/context.html">Context</a>
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								represents a web application.  A Host may contain multiple
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								contexts, each with a unique path.  The
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								<a href="../../catalina/docs/api/org/apache/catalina/Context.html">Context
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								interface</a> may be implemented to create custom Contexts, but
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								this is rarely the case because the
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								<a href="../../catalina/docs/api/org/apache/catalina/core/StandardContext.html">
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								StandardContext</a> provides significant additional functionality.
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								</p>
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								</blockquote></td></tr></table>
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								</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Comments"><strong>Comments</strong></a></font></td></tr><tr><td><blockquote>
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								<p>
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								Tomcat is designed to be a fast and efficient implementation of the
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								Servlet Specification.  Tomcat came about as the reference implementation
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								of this specification, and has remained rigorous in adhering to the
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								specification.  At the same time, significant attention has been paid
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								to Tomcat's performance and it is now on par with other servlet containers,
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								including commercial ones.
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								</p>
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								<p>
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								In recent releases of Tomcat, mostly starting with Tomcat 5,
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								we have begun effots to make more aspects of Tomcat managable via
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								JMX.  In addition, the Manager and Admin webapps have been greatly
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								enhanced and improved.  Managability is a primary area of concern
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								for us as the product matures and the specification becomes more
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								stable.
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								</p>
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								</blockquote></td></tr></table></td></tr><!--FOOTER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><!--PAGE FOOTER--><tr><td colspan="2"><div align="center"><font color="#525D76" size="-1"><em>
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								        Copyright © 1999-2006, Apache Software Foundation
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								        </em></font></div></td></tr></table></body></html>
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