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 <html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Catalina Functional Specifications (6.0.39) - Invoker Servlet</title><meta name="author" content="Craig McClanahan"><style type="text/css" media="print">
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 		</style></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="
       Catalina Functional Specifications
     " border="0"></a></td><td><h1><font face="arial,helvetica,sanserif">Apache Tomcat 6.0</font></h1><font face="arial,helvetica,sanserif">Version 6.0.39, Jan 27 2014</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><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap="nowrap" class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Functional Specs</a></li></ul><p><strong>Administrative Apps</strong></p><ul><li><a href="fs-admin-apps.html">Overall Requirements</a></li><li><a href="mbean-names.html">Tomcat MBean Names</a></li><li><a href="fs-admin-objects.html">Administered Objects</a></li><li><a href="fs-admin-opers.html">Supported Operations</a></li></ul><p><strong>Internal Servlets</strong></p><ul><li><a href="fs-default.html">Default Servlet</a></li><li><a href="fs-invoker.html">Invoker Servlet</a></li></ul><p><strong>Realm Implementations</strong></p><ul><li><a href="fs-jdbc-realm.html">JDBC Realm</a></li><li><a href="fs-jndi-realm.html">JNDI Realm</a></li><li><a href="fs-memory-realm.html">Memory Realm</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>Catalina Functional Specifications</h1><h2>Invoker Servlet</h2><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Table of Contents"><!--()--></a><a name="Table_of_Contents"><strong>Table of Contents</strong></a></font></td></tr><tr><td><blockquote>
 <ul><li><a href="#Overview">Overview</a><ol><li><a href="#Introduction">Introduction</a></li><li><a href="#External_Specifications">External Specifications</a></li><li><a href="#Implementation_Requirements">Implementation Requirements</a></li></ol></li><li><a href="#Dependencies">Dependencies</a><ol><li><a href="#Environmental_Dependencies">Environmental Dependencies</a></li><li><a href="#Container_Dependencies">Container Dependencies</a></li></ol></li><li><a href="#Functionality">Functionality</a><ol><li><a href="#Initialization_Functionality">Initialization Functionality</a></li><li><a href="#Per-Request_Functionality">Per-Request Functionality</a></li><li><a href="#Finalization_Functionality">Finalization Functionality</a></li></ol></li><li><a href="#Testable_Assertions">Testable Assertions</a></li></ul>
 </blockquote></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>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote>

     <p>The purpose of the <strong>Invoker Servlet</strong> is to allow a
     web application to dynamically register new <em>servlet definitions</em>
     that correspond with a <code>&lt;servlet&gt;</code> element in the
     <code>/WEB-INF/web.xml</code> deployment descriptor, and execute
     requests utilizing the new servlet definitions.  From the perspective
     of the newly registered servlets, all servlet lifecycle requirements
     of the Servlet Specification (such as calling <code>init()</code> and
     <code>destroy()</code> at the correct times) will be respected.</p>

   </blockquote></td></tr></table>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="External Specifications"><!--()--></a><a name="External_Specifications"><strong>External Specifications</strong></a></font></td></tr><tr><td><blockquote>

     <p>I do not know of any formal specification of the behavior of an
     invoker servlet that is publicly available.  Anyone know of one?</p>

   </blockquote></td></tr></table>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Implementation Requirements"><!--()--></a><a name="Implementation_Requirements"><strong>Implementation Requirements</strong></a></font></td></tr><tr><td><blockquote>

     <p>The implementation of this functionality shall conform to the
     following requirements:</p>
     <ul>
     <li>Implemented as a servlet.</li>
     <li>Exist in the <code>org.apache.catalina.servlets</code> package
         so that it can be loaded by the Catalina class loader.</li>
     <li>Implement the <code>org.apache.catalina.ContainerServlet</code>
         interface, so that it gains knowledge of the <code>Wrapper</code>
         that is responsible for itself and, therefore, access to other
         internal Catalina components.</li>
     <li>Support a configurable debugging detail level.</li>
     <li>Log debugging and operational messages (suitably internationalized)
         via the <code>getServletContext().log()</code> method.</li>
     </ul>

   </blockquote></td></tr></table>


 </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Dependencies"><strong>Dependencies</strong></a></font></td></tr><tr><td><blockquote>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Environmental Dependencies"><!--()--></a><a name="Environmental_Dependencies"><strong>Environmental Dependencies</strong></a></font></td></tr><tr><td><blockquote>

     <p>The following environmental dependencies must be met in order for
     the Invoker servlet to operate correctly:</p>
     <ul>
     <li>The invoker servlet must be registered in the application deployment
         descriptor (or the default deployment descriptor in file
         <code>$CATALINA_BASE/conf/web.xml</code>) using a "path mapped"
         servlet mapping.  The historical default mapping is to URL pattern
         "<code>/servlet/*</code>", although the invoker servlet must operate
         correctly with an arbitrary mapping.</li>
     </ul>

   </blockquote></td></tr></table>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Container Dependencies"><!--()--></a><a name="Container_Dependencies"><strong>Container Dependencies</strong></a></font></td></tr><tr><td><blockquote>

     <p>Correct operation of the invoker servlet depends on the following
     specific features of the surrounding container:</p>
     <ul>
     <li>Correct support for the <code>ContainerServlet</code> interface,
         including calling <code>setWrapper()</code> <strong>before</strong>
         the <code>init()</code> method of the invoker servlet is called.</li>
     <li>The web application class loader must be stored as the context
         class loader of the request processing thread.</li>
     </ul>

   </blockquote></td></tr></table>


 </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Functionality"><strong>Functionality</strong></a></font></td></tr><tr><td><blockquote>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Initialization Functionality"><!--()--></a><a name="Initialization_Functionality"><strong>Initialization Functionality</strong></a></font></td></tr><tr><td><blockquote>

     <p>The following processing must be performed when the <code>init()</code>
     method of the invoker servlet is called:</p>
     <ul>
     <li>Ensure that the container has called <code>setWrapper()</code>.  If
         not, throw a permanent <code>UnavailableException</code>.</li>
     <li>Look up and cache the <code>Context</code> that corresponds to our
         <code>Wrapper</code>.  This is the component with which new servlet
         definitions and mappings will be registered.</li>
     </ul>

   </blockquote></td></tr></table>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Per-Request Functionality"><!--()--></a><a name="Per-Request_Functionality"><strong>Per-Request Functionality</strong></a></font></td></tr><tr><td><blockquote>

     <p>On each request, the following processing shall be performed:</p>
     <ol>
     <li>Calculate the <code>{ServletPath}</code> for this request, either from
         request attribute <code>javax.servlet.include.servlet_path</code> or
         by calling <code>request.getServletPath()</code>.</li>
     <li>Calculate the <code>{PathInfo}</code> for this request, either from
         request attribute <code>javax.servlet.include.path_info</code> or
         by calling <code>request.getPathInfo()</code>.  If the calculated
         <code>{PathInfo}</code> is null, return HTTP status 400
         (bad request).</li>
     <li>Parse the calculated <code>{PathInfo}</code> value as follows:
         <ol>
         <li>Ignore the leading slash character.</li>
         <li>Accumulate characters up to the next '/' (if any) as the
             <code>{ServletSelector}</code>.</li>
         <li>If a '/' was encountered, accumulate all characters from that
             slash (inclusive) to the end of the string as
             <code>{PathRemainder}</code>.  If no slash was encountered,
             set <code>{PathRemainder}</code> to a zero-length string.</li>
         </ol></li>
     <li>Determine whether <code>{ServletSelector}</code> is the name of an
         existing servlet definition, and process it as follows:
         <ol>
         <li>Ask our associated <code>Context</code> to find and return a
             child <code>Wrapper</code> named <code>{ServletSelector}</code>.
             </li>
         <li>If there is no such child, skip to the next major step.</li>
         <li>Register a new servlet mapping for this <code>Wrapper</code>,
             using a URL pattern calculated as follows:
             <code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
             + "/*"</li>
         <li>Create a request dispatcher using a path calculated as follows:
             <code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
             + <code>{PathRemainder}</code></li>
         <li>Forward this request to the created request dispatcher, and
             exit from this request.</li>
         </ol></li>
     <li>Assume that <code>{ServletSelector}</code> is the fully qualified
         name of a Java class that implements <code>javax.servlet.Servlet</code>
         and process it as follows:
         <ol>
         <li>Synthesize a new <code>{ServletName}</code> for the servlet
             definition that will be created.</li>
         <li>If there is already a child <code>Wrapper</code> associated with
             this name, return HTTP status 500 (internal server error), because
             a mapping should have already been created for this servlet.</li>
         <li>Attempt to load a class named <code>{ServletSelector}</code> from
             the web application class loader (i.e. the context class loader
             for our current thread).  If this fails, return HTTP status 404
             (not found).</li>
         <li>Instantiate an instance of this class.  If an error occurs,
             return HTTP status 404 (not found).</li>
         <li>If this class does not implement the
             <code>javax.servlet.Servlet</code> interface, return HTTP status
             404 (not found).</li>
         <li>Create and register a new <code>Wrapper</code> child with our
             <code>Context</code>, under name <code>{ServletName}</code>.</li>
         <li>Register a new servlet mapping for this <code>Wrapper</code>,
             using a URL pattern calculated as follows:
             <code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
             + "/*"</li>
         <li>Create a request dispatcher using a path calculated as follows:
             <code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
             + <code>{PathRemainder}</code></li>
         <li>Forward this request to the created request dispatcher, and
             exit from this request.</li>
         </ol></li>
     </ol>

   </blockquote></td></tr></table>


   <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Finalization Functionality"><!--()--></a><a name="Finalization_Functionality"><strong>Finalization Functionality</strong></a></font></td></tr><tr><td><blockquote>

     <p>No specific processing is required when the <code>destroy()</code>
     method is called:</p>

   </blockquote></td></tr></table>


 </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Testable Assertions"><!--()--></a><a name="Testable_Assertions"><strong>Testable Assertions</strong></a></font></td></tr><tr><td><blockquote>

   <p>In addition the the assertions implied by the functionality requirements
   listed above, the following additional assertions shall be tested to
   validate the behavior of the invoker servlet:</p>
   <ul>
   <li>It is possible to access an existing servlet definition by name
       through the invoker.  The existing servlet definition can include
       either a <code>&lt;servlet-class&gt;</code> or
       <code>&lt;jsp-file&gt;</code> subelement.</li>
   <li>When an existing servlet definition is accessed by name, the request
       will be ultimately processed by the same servlet instance that would
       have processed it had a mapping to that servlet definition been used
       on the request directly.</li>
   <li>It is possible to access an anonymous servlet by class name
       through the invoker.</li>
   <li>When an anonymous servlet is accessed, the servlet instance is processed
       according to the lifecycle requirements of the Servlet Specification.
       </li>
   <li>When an anonymous servlet is accessed, the servlet instance receives
       a <code>ServletConfig</code> instance with no servlet initialization
       parameters.</li>
   <li>It is possible to utilize the invoker servlet via a direct request.</li>
   <li>It is possible to utilize the invoker servlet via a call to
       <code>RequestDispatcher.forward()</code>, or the corresponding
       <code>&lt;jsp:forward&gt;</code> tag in a JSP page.</li>
   <li>It is possible to utilize the invoker servlet via a call to
       <code>RequestDispatcher.include()</code>, or the corresponding
       <code>&lt;jsp:include&gt;</code> tag in a JSP page.</li>
   <li>It is possible to use any HTTP method (including GET and POST) that
       is supported by the Servlet class that is ultimately executed.</li>
   <li>The invoker servlet should never be asked to process a second or
       subsequent request for the same <code>{ServletSelector}</code> (because
       it will have registered an appropriate servlet mapping.</li>
   </ul>

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         Copyright &copy; 1999-2014, Apache Software Foundation
         </em></font></div></td></tr></table></body></html>
	<html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Catalina Functional Specifications (6.0.39) - Invoker Servlet</title><meta name="author" content="Craig McClanahan"><style type="text/css" media="print">
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	</style></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="
	Catalina Functional Specifications
	" border="0"></a></td><td><h1><font face="arial,helvetica,sanserif">Apache Tomcat 6.0</font></h1><font face="arial,helvetica,sanserif">Version 6.0.39, Jan 27 2014</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><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap="nowrap" class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Functional Specs</a></li></ul><p><strong>Administrative Apps</strong></p><ul><li><a href="fs-admin-apps.html">Overall Requirements</a></li><li><a href="mbean-names.html">Tomcat MBean Names</a></li><li><a href="fs-admin-objects.html">Administered Objects</a></li><li><a href="fs-admin-opers.html">Supported Operations</a></li></ul><p><strong>Internal Servlets</strong></p><ul><li><a href="fs-default.html">Default Servlet</a></li><li><a href="fs-invoker.html">Invoker Servlet</a></li></ul><p><strong>Realm Implementations</strong></p><ul><li><a href="fs-jdbc-realm.html">JDBC Realm</a></li><li><a href="fs-jndi-realm.html">JNDI Realm</a></li><li><a href="fs-memory-realm.html">Memory Realm</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>Catalina Functional Specifications</h1><h2>Invoker Servlet</h2><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Table of Contents"><!--()--></a><a name="Table_of_Contents"><strong>Table of Contents</strong></a></font></td></tr><tr><td><blockquote>
	<ul><li><a href="#Overview">Overview</a><ol><li><a href="#Introduction">Introduction</a></li><li><a href="#External_Specifications">External Specifications</a></li><li><a href="#Implementation_Requirements">Implementation Requirements</a></li></ol></li><li><a href="#Dependencies">Dependencies</a><ol><li><a href="#Environmental_Dependencies">Environmental Dependencies</a></li><li><a href="#Container_Dependencies">Container Dependencies</a></li></ol></li><li><a href="#Functionality">Functionality</a><ol><li><a href="#Initialization_Functionality">Initialization Functionality</a></li><li><a href="#Per-Request_Functionality">Per-Request Functionality</a></li><li><a href="#Finalization_Functionality">Finalization Functionality</a></li></ol></li><li><a href="#Testable_Assertions">Testable Assertions</a></li></ul>
	</blockquote></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>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote>

	<p>The purpose of the <strong>Invoker Servlet</strong> is to allow a
	web application to dynamically register new <em>servlet definitions</em>
	that correspond with a <code><servlet></code> element in the
	<code>/WEB-INF/web.xml</code> deployment descriptor, and execute
	requests utilizing the new servlet definitions. From the perspective
	of the newly registered servlets, all servlet lifecycle requirements
	of the Servlet Specification (such as calling <code>init()</code> and
	<code>destroy()</code> at the correct times) will be respected.</p>

	</blockquote></td></tr></table>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="External Specifications"><!--()--></a><a name="External_Specifications"><strong>External Specifications</strong></a></font></td></tr><tr><td><blockquote>

	<p>I do not know of any formal specification of the behavior of an
	invoker servlet that is publicly available. Anyone know of one?</p>

	</blockquote></td></tr></table>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Implementation Requirements"><!--()--></a><a name="Implementation_Requirements"><strong>Implementation Requirements</strong></a></font></td></tr><tr><td><blockquote>

	<p>The implementation of this functionality shall conform to the
	following requirements:</p>
	<ul>
	<li>Implemented as a servlet.</li>
	<li>Exist in the <code>org.apache.catalina.servlets</code> package
	so that it can be loaded by the Catalina class loader.</li>
	<li>Implement the <code>org.apache.catalina.ContainerServlet</code>
	interface, so that it gains knowledge of the <code>Wrapper</code>
	that is responsible for itself and, therefore, access to other
	internal Catalina components.</li>
	<li>Support a configurable debugging detail level.</li>
	<li>Log debugging and operational messages (suitably internationalized)
	via the <code>getServletContext().log()</code> method.</li>
	</ul>

	</blockquote></td></tr></table>


	</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Dependencies"><strong>Dependencies</strong></a></font></td></tr><tr><td><blockquote>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Environmental Dependencies"><!--()--></a><a name="Environmental_Dependencies"><strong>Environmental Dependencies</strong></a></font></td></tr><tr><td><blockquote>

	<p>The following environmental dependencies must be met in order for
	the Invoker servlet to operate correctly:</p>
	<ul>
	<li>The invoker servlet must be registered in the application deployment
	descriptor (or the default deployment descriptor in file
	<code>$CATALINA_BASE/conf/web.xml</code>) using a "path mapped"
	servlet mapping. The historical default mapping is to URL pattern
	"<code>/servlet/*</code>", although the invoker servlet must operate
	correctly with an arbitrary mapping.</li>
	</ul>

	</blockquote></td></tr></table>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Container Dependencies"><!--()--></a><a name="Container_Dependencies"><strong>Container Dependencies</strong></a></font></td></tr><tr><td><blockquote>

	<p>Correct operation of the invoker servlet depends on the following
	specific features of the surrounding container:</p>
	<ul>
	<li>Correct support for the <code>ContainerServlet</code> interface,
	including calling <code>setWrapper()</code> <strong>before</strong>
	the <code>init()</code> method of the invoker servlet is called.</li>
	<li>The web application class loader must be stored as the context
	class loader of the request processing thread.</li>
	</ul>

	</blockquote></td></tr></table>


	</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Functionality"><strong>Functionality</strong></a></font></td></tr><tr><td><blockquote>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Initialization Functionality"><!--()--></a><a name="Initialization_Functionality"><strong>Initialization Functionality</strong></a></font></td></tr><tr><td><blockquote>

	<p>The following processing must be performed when the <code>init()</code>
	method of the invoker servlet is called:</p>
	<ul>
	<li>Ensure that the container has called <code>setWrapper()</code>. If
	not, throw a permanent <code>UnavailableException</code>.</li>
	<li>Look up and cache the <code>Context</code> that corresponds to our
	<code>Wrapper</code>. This is the component with which new servlet
	definitions and mappings will be registered.</li>
	</ul>

	</blockquote></td></tr></table>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Per-Request Functionality"><!--()--></a><a name="Per-Request_Functionality"><strong>Per-Request Functionality</strong></a></font></td></tr><tr><td><blockquote>

	<p>On each request, the following processing shall be performed:</p>
	<ol>
	<li>Calculate the <code>{ServletPath}</code> for this request, either from
	request attribute <code>javax.servlet.include.servlet_path</code> or
	by calling <code>request.getServletPath()</code>.</li>
	<li>Calculate the <code>{PathInfo}</code> for this request, either from
	request attribute <code>javax.servlet.include.path_info</code> or
	by calling <code>request.getPathInfo()</code>. If the calculated
	<code>{PathInfo}</code> is null, return HTTP status 400
	(bad request).</li>
	<li>Parse the calculated <code>{PathInfo}</code> value as follows:
	<ol>
	<li>Ignore the leading slash character.</li>
	<li>Accumulate characters up to the next '/' (if any) as the
	<code>{ServletSelector}</code>.</li>
	<li>If a '/' was encountered, accumulate all characters from that
	slash (inclusive) to the end of the string as
	<code>{PathRemainder}</code>. If no slash was encountered,
	set <code>{PathRemainder}</code> to a zero-length string.</li>
	</ol></li>
	<li>Determine whether <code>{ServletSelector}</code> is the name of an
	existing servlet definition, and process it as follows:
	<ol>
	<li>Ask our associated <code>Context</code> to find and return a
	child <code>Wrapper</code> named <code>{ServletSelector}</code>.
	</li>
	<li>If there is no such child, skip to the next major step.</li>
	<li>Register a new servlet mapping for this <code>Wrapper</code>,
	using a URL pattern calculated as follows:
	<code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
	+ "/*"</li>
	<li>Create a request dispatcher using a path calculated as follows:
	<code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
	+ <code>{PathRemainder}</code></li>
	<li>Forward this request to the created request dispatcher, and
	exit from this request.</li>
	</ol></li>
	<li>Assume that <code>{ServletSelector}</code> is the fully qualified
	name of a Java class that implements <code>javax.servlet.Servlet</code>
	and process it as follows:
	<ol>
	<li>Synthesize a new <code>{ServletName}</code> for the servlet
	definition that will be created.</li>
	<li>If there is already a child <code>Wrapper</code> associated with
	this name, return HTTP status 500 (internal server error), because
	a mapping should have already been created for this servlet.</li>
	<li>Attempt to load a class named <code>{ServletSelector}</code> from
	the web application class loader (i.e. the context class loader
	for our current thread). If this fails, return HTTP status 404
	(not found).</li>
	<li>Instantiate an instance of this class. If an error occurs,
	return HTTP status 404 (not found).</li>
	<li>If this class does not implement the
	<code>javax.servlet.Servlet</code> interface, return HTTP status
	404 (not found).</li>
	<li>Create and register a new <code>Wrapper</code> child with our
	<code>Context</code>, under name <code>{ServletName}</code>.</li>
	<li>Register a new servlet mapping for this <code>Wrapper</code>,
	using a URL pattern calculated as follows:
	<code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
	+ "/*"</li>
	<li>Create a request dispatcher using a path calculated as follows:
	<code>{ServletPath}</code> + "/" + <code>{ServletSelector}</code>
	+ <code>{PathRemainder}</code></li>
	<li>Forward this request to the created request dispatcher, and
	exit from this request.</li>
	</ol></li>
	</ol>

	</blockquote></td></tr></table>


	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Finalization Functionality"><!--()--></a><a name="Finalization_Functionality"><strong>Finalization Functionality</strong></a></font></td></tr><tr><td><blockquote>

	<p>No specific processing is required when the <code>destroy()</code>
	method is called:</p>

	</blockquote></td></tr></table>


	</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Testable Assertions"><!--()--></a><a name="Testable_Assertions"><strong>Testable Assertions</strong></a></font></td></tr><tr><td><blockquote>

	<p>In addition the the assertions implied by the functionality requirements
	listed above, the following additional assertions shall be tested to
	validate the behavior of the invoker servlet:</p>
	<ul>
	<li>It is possible to access an existing servlet definition by name
	through the invoker. The existing servlet definition can include
	either a <code><servlet-class></code> or
	<code><jsp-file></code> subelement.</li>
	<li>When an existing servlet definition is accessed by name, the request
	will be ultimately processed by the same servlet instance that would
	have processed it had a mapping to that servlet definition been used
	on the request directly.</li>
	<li>It is possible to access an anonymous servlet by class name
	through the invoker.</li>
	<li>When an anonymous servlet is accessed, the servlet instance is processed
	according to the lifecycle requirements of the Servlet Specification.
	</li>
	<li>When an anonymous servlet is accessed, the servlet instance receives
	a <code>ServletConfig</code> instance with no servlet initialization
	parameters.</li>
	<li>It is possible to utilize the invoker servlet via a direct request.</li>
	<li>It is possible to utilize the invoker servlet via a call to
	<code>RequestDispatcher.forward()</code>, or the corresponding
	<code><jsp:forward></code> tag in a JSP page.</li>
	<li>It is possible to utilize the invoker servlet via a call to
	<code>RequestDispatcher.include()</code>, or the corresponding
	<code><jsp:include></code> tag in a JSP page.</li>
	<li>It is possible to use any HTTP method (including GET and POST) that
	is supported by the Servlet class that is ultimately executed.</li>
	<li>The invoker servlet should never be asked to process a second or
	subsequent request for the same <code>{ServletSelector}</code> (because
	it will have registered an appropriate servlet mapping.</li>
	</ul>

	</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>
	Copyright © 1999-2014, Apache Software Foundation
	</em></font></div></td></tr></table></body></html>