container/webapps/docs/config/defaultcontext.xml - tomcat55 - Git at Google

 <?xml version="1.0"?>
 <!DOCTYPE document [
   <!ENTITY project SYSTEM "project.xml">
 ]>
 <document url="defaultcontext.html">

   &project;

   <properties>
     <author email="craigmcc@apache.org">Craig R. McClanahan</author>
     <title>The DefaultContext Component</title>
   </properties>

 <body>


 <section name="Introduction">

   <p>The <strong>DefaultContext</strong> element represents a subset of
   the configuration settings for a <a href="context.html">Context</a>,
   and can be nested inside an <a href="engine.html">Engine</a> or
   <a href="host.html">Host</a> element to represent <em>default
   configuration properties</em> for Contexts that are automatically
   created.</p>

   <p>See <a href="host.html#Automatic Application Deployment">Automatic
   Application Deployment</a> and
   <a href="host.html#User Web Applications">User Web Applications</a>
   for more information about the circumstances in which Catalina will
   automatically create Contexts for you, based on the configuration
   properties that are stored here.</p>

 </section>


 <section name="Attributes">

   <subsection name="Common Attributes">

     <p>All implementations of <strong>Host</strong>
     support the following attributes:</p>

     <attributes>

       <attribute name="cookies" required="false">
         <p>Set to <code>true</code> if you want cookies to be used for
         session identifier communication if supported by the client (this
         is the default).  Set to <code>false</code> if you want to disable
         the use of cookies for session identifier communication, and rely
         only on URL rewriting by the application.</p>
       </attribute>

       <attribute name="crossContext" required="false">
         <p>Set to <code>true</code> if you want calls within this application
         to <code>ServletContext.getContext()</code> to successfully return a
         request dispatcher for other web applications running on this virtual
         host.  Set to <code>false</code> (the default) in security
         conscious environments, to make <code>getContext()</code> always
         return <code>null</code>.</p>
       </attribute>

       <attribute name="reloadable" required="false">
         <p>Set to <code>true</code> if you want Catalina to monitor classes in
         <code>/WEB-INF/classes/</code> and <code>/WEB-INF/lib</code> for
         changes, and automatically reload the web application if a change
         is detected.  This feature is very useful during application
         development, but it requires significant runtime overhead and is
         not recommended for use on deployed production applications.  You
         can use the <a href="../manager-howto.html">Manager</a> web
         application, however, to trigger reloads of deployed applications
         on demand.</p>
       </attribute>

       <attribute name="wrapperClass" required="false">
         <p>Java class name of the <code>org.apache.catalina.Wrapper</code>
         implementation class that will be used for servlets managed by this
         Context.  If not specified, a standard default value will be used.</p>
       </attribute>

     </attributes>

   </subsection>


   <subsection name="Standard Implementation">

     <p>The standard implementation of <strong>DefaultContext</strong> is
     <strong>org.apache.catalina.core.DefaultContext</strong>.
     It supports the following additional attributes (in addition to the
     common attributes listed above):</p>

     <attributes>

       <attribute name="allowLinking" required="false">
         <p>If the value of this flag is <code>true</code>, symlinks will be
         allowed inside the web application, pointing to resources outside the
         web application base path. If not specified, the default value
         of the flag is <code>false</code>.</p>
         <p><b>NOTE: This flag MUST NOT be set to true on the Windows platform
         (or any other OS which does not have a case sensitive filesystem),
         as it will disable case sensitivity checks, allowing JSP source code
         disclosure, among other security problems.</b></p>
       </attribute>

       <attribute name="cacheMaxSize" required="false">
         <p>Maximum size of the static resource cache in kilobytes.
         If not specified, the default value is <code>10240</code>
         (10 megabytes).</p>
       </attribute>

       <attribute name="cacheTTL" required="false">
         <p>Amount of time in milliseconds between cache entries revalidation.
         If not specified, the default value is <code>5000</code>
         (5 seconds).</p>
       </attribute>

       <attribute name="cachingAllowed" required="false">
         <p>If the value of this flag is <code>true</code>, the cache for static
         resources will be used. If not specified, the default value
         of the flag is <code>true</code>.</p>
       </attribute>

       <attribute name="caseSensitive" required="false">
         <p>If the value of this flag is <code>true</code>, all case sensitivity
         checks will be disabled. If not
         specified, the default value of the flag is <code>true</code>.</p>
         <p><b>NOTE: This flag MUST NOT be set to false on the Windows platform
         (or any other OS which does not have a case sensitive filesystem),
         as it will disable case sensitivity checks, allowing JSP source code
         disclosure, among other security problems.</b></p>
       </attribute>

       <attribute name="managerChecksFrequency" required="false">
         <p>Frequency of the session expiration, and related manager operations.
         Manager operations will be done once for the specified amount of
         backgrondProcess calls (ie, the lower the amount, the most often the
         checks will occur). The minimum value is 1, and the default value is 6.
         </p>
       </attribute>

       <attribute name="swallowOutput" required="false">
         <p>If the value of this flag is <code>true</code>, the bytes output to
         System.out and System.err by the web application will be redirected to
         the web application logger. If not specified, the default value
         of the flag is <code>false</code>.</p>
       </attribute>

       <attribute name="useNaming" required="false">
         <p>Set to <code>true</code> (the default) to have Catalina enable a
         JNDI <code>InitialContext</code> for this web application that is
         compatible with Java2 Enterprise Edition (J2EE) platform
         conventions.</p>
       </attribute>

     </attributes>

   </subsection>


 </section>


 <section name="Nested Components">

   <p>You can nest at most one instance of the following utility components
   by nesting a corresponding element inside your
   <strong>DefaultContext</strong> element:</p>
   <ul>
   <li><a href="loader.html"><strong>Loader</strong></a> -
       Configure the web application class loader that will be used to load
       servlet and bean classes for each web application.  Normally, the
       default configuration of the class loader will be sufficient.</li>
   <!--
   <li><a href="logger.html"><strong>Logger</strong></a> -
       Configure a logger that will receive
       and process all log messages for each <strong>Context</strong>.  This
       includes application messages logged via calls to
       <code>ServletContext.log()</code>.</li>
   <li><a href="manager.html"><strong>Manager</strong></a> -
       Configure the session manager that will be used to create, destroy,
       and persist HTTP sessions for each web application.  Normally, the
       default configuration of the session manager will be sufficient.</li>
   <li><a href="realm.html"><strong>Realm</strong></a> -
       Configure a realm that will allow its
       database of users, and their associated roles, to be utilized solely
       for each particular web application.  If not specified, this web
       application will utilize the Realm associated with the owning
       <a href="host.html">Host</a> or <a href="engine.html">Engine</a>.</li>
   <li><a href="resources.html"><strong>Resources</strong></a> -
       Configure the resource manager that will be used to access the static
       resources associated with each web application.  Normally, the
       default configuration of the resource manager will be sufficient.</li>
   -->
   </ul>

 </section>


 <section name="Special Features">


   <subsection name="Context Parameters">

     <p>You can configure named values that will be made visible to
     web applications as servlet context initialization parameters by nesting
     <code>&lt;Parameter&gt;</code> elements inside this element.  For
     example, you can create an initialization parameter like this:</p>
 <source>
 &lt;DefaultContext ...&gt;
   ...
   &lt;Parameter name="companyName" value="My Company, Incorporated"
          override="false"/&gt;
   ...
 &lt;/DefaultContext&gt;
 </source>

     <p>This is equivalent to the inclusion of the following element in the
     web application deployment descriptor (<code>/WEB-INF/web.xml</code>):
     </p>
 <source>
 &lt;context-param&gt;
   &lt;param-name&gt;companyName&lt;/param-name&gt;
   &lt;param-value&gt;My Company, Incorporated&lt;/param-value&gt;
 &lt;/context-param&gt;
 </source>
     <p>but does <em>not</em> require modification of the deployment descriptor
     to customize this value.</p>

     <p>The valid attributes for a <code>&lt;Parameter&gt;</code> element
     are as follows:</p>

     <attributes>

       <attribute name="description" required="false">
         <p>Optional, human-readable description of this context
         initialization parameter.</p>
       </attribute>

       <attribute name="name" required="true">
         <p>The name of the context initialization parameter to be created.</p>
       </attribute>

       <attribute name="override" required="false">
         <p>Set this to <code>false</code> if you do <strong>not</strong> want
         a <code>&lt;context-param&gt;</code> for the same parameter name,
         found in the web application deployment descriptor, to override the
         value specified here.  By default, overrides are allowed.</p>
       </attribute>

       <attribute name="value" required="true">
         <p>The parameter value that will be presented to the application
         when requested by calling
         <code>ServletContext.getInitParameter()</code>.</p>
       </attribute>

     </attributes>

   </subsection>


   <subsection name="Environment Entries">

     <p>You can configure named values that will be made visible to
     web applications as environment entry resources, by nesting
     <code>&lt;Environment&gt;</code> entries inside this element.  For
     example, you can create an environment entry like this:</p>
 <source>
 &lt;DefaultContext ...&gt;
   ...
   &lt;Environment name="maxExemptions" value="10"
          type="java.lang.Integer" override="false"/&gt;
   ...
 &lt;/DefaultContext&gt;
 </source>

     <p>This is equivalent to the inclusion of the following element in the
     web application deployment descriptor (<code>/WEB-INF/web.xml</code>):
     </p>
 <source>
 &lt;env-entry&gt;
   &lt;env-entry-name&gt;maxExemptions&lt;/param-name&gt;
   &lt;env-entry-value&gt;10&lt;/env-entry-value&gt;
   &lt;env-entry-type&gt;java.lang.Integer&lt;/env-entry-type&gt;
 &lt;/env-entry&gt;
 </source>
     <p>but does <em>not</em> require modification of the deployment descriptor
     to customize this value.</p>

     <p>The valid attributes for an <code>&lt;Environment&gt;</code> element
     are as follows:</p>

     <attributes>

       <attribute name="description" required="false">
         <p>Optional, human-readable description of this environment entry.</p>
       </attribute>

       <attribute name="name" required="true">
         <p>The name of the environment entry to be created, relative to the
         <code>java:comp/env</code> context.</p>
       </attribute>

       <attribute name="override" required="false">
         <p>Set this to <code>false</code> if you do <strong>not</strong> want
         an <code>&lt;env-entry&gt;</code> for the same environment entry name,
         found in the web application deployment descriptor, to override the
         value specified here.  By default, overrides are allowed.</p>
       </attribute>

       <attribute name="type" required="true">
         <p>The fully qualified Java class name expected by the web application
         for this environment entry.  Must be one of the legal values for
         <code>&lt;env-entry-type&gt;</code> in the web application deployment
         descriptor:  <code>java.lang.Boolean</code>,
         <code>java.lang.Byte</code>, <code>java.lang.Character</code>,
         <code>java.lang.Double</code>, <code>java.lang.Float</code>,
         <code>java.lang.Integer</code>, <code>java.lang.Long</code>,
         <code>java.lang.Short</code>, or <code>java.lang.String</code>.</p>
       </attribute>

       <attribute name="value" required="true">
         <p>The parameter value that will be presented to the application
         when requested from the JNDI context.  This value must be convertable
         to the Java type defined by the <code>type</code> attribute.</p>
       </attribute>

     </attributes>

   </subsection>


   <subsection name="Lifecycle Listeners">

     <p>If you have implemented a Java object that needs to know when this
     <strong>Context</strong> is started or stopped, you can declare it by
     nesting a <strong>Listener</strong> element inside this element.  The
     class name you specify must implement the
     <code>org.apache.catalina.LifecycleListener</code> interface, and
     it will be notified about the occurrence of the coresponding
     lifecycle events.  Configuration of such a listener looks like this:</p>

 <source>
 &lt;DefaultContext  ...&gt;
   ...
   &lt;Listener className="com.mycompany.mypackage.MyListener" ... &gt;
   ...
 &lt;/DefaultContext&gt;
 </source>

     <p>Note that a Listener can have any number of additional properties
     that may be configured from this element.  Attribute names are matched
     to corresponding JavaBean property names using the standard property
     method naming patterns.</p>

   </subsection>


   <subsection name="Resource Definitions">

     <p>You can declare the characteristics of the resource
     to be returned for JNDI lookups of <code>&lt;resource-ref&gt;</code> and
     <code>&lt;resource-env-ref&gt;</code> elements in the web application
     deployment descriptor.  You <strong>MUST</strong> also define
     <a href="#Resource Parameters">Resource Parameters</a>
     for the same resource name, to configure
     the object factory to be used (if not known to Tomcat already), and
     the properties used to configure that object factory.</p>

     <p>For example, you can create a resource definition like this:</p>
 <source>
 &lt;DefaultContext ...&gt;
   ...
   &lt;Resource name="jdbc/EmployeeDB" auth="Container"
             type="javax.sql.DataSource"
      description="Employees Database for HR Applications"/&gt;
   ...
 &lt;/DefaultContext&gt;
 </source>

     <p>This is equivalent to the inclusion of the following element in the
     web application deployment descriptor (<code>/WEB-INF/web.xml</code>):</p>
 <source>
 &lt;resource-ref&gt;
   &lt;description&gt;Employees Database for HR Applications&lt;/description&gt;
   &lt;res-ref-name&gt;jdbc/EmployeeDB&lt;/res-ref-name&gt;
   &lt;res-ref-type&gt;javax.sql.DataSource&lt;/res-ref-type&gt;
   &lt;res-auth&gt;Container&lt;/res-auth&gt;
 &lt;/resource-ref&gt;
 </source>

     <p>but does <em>not</em> require modification of the deployment
     descriptor to customize this value.</p>

     <p>The valid attriutes for a <code>&lt;Resource&gt;</code> element
     are as follows:</p>

     <attributes>

       <attribute name="auth" required="false">
         <p>Specify whether the web Application code signs on to the
         corresponding resource manager programatically, or whether the
         Container will sign on to the resource manager on behalf of the
         application.  The value of this attribute must be
         <code>Application</code> or <code>Container</code>.  This
         attribute is <strong>required</strong> if the web application
         will use a <code>&lt;resource-ref&gt;</code> element in the web
         application deployment descriptor, but is optional if the
         application uses a <code>&lt;resource-env-ref&gt;</code> instead.</p>
       </attribute>

       <attribute name="description" required="false">
         <p>Optional, human-readable description of this resource.</p>
       </attribute>

       <attribute name="name" required="true">
         <p>The name of the resource to be created, relative to the
         <code>java:comp/env</code> context.</p>
       </attribute>

       <attribute name="scope" required="false">
         <p>Specify whether connections obtained through this resource
         manager can be shared.  The value of this attribute must be
         <code>Shareable</code> or <code>Unshareable</code>.  By default,
         connections are assumed to be shareable.</p>
       </attribute>

       <attribute name="type" required="true">
         <p>The fully qualified Java class name expected by the web
         application when it performs a lookup for this resource.</p>
       </attribute>

     </attributes>


   </subsection>


   <subsection name="Resource Parameters">

     <p>This element is used to configure the resource manager (or object
     factory) used to return objects when the web application performs a
     JNDI lookup operation on the corresponding resource name.  You
     <strong>MUST</strong> define resource parameters for every resource name
     that is specified by a <code>&lt;Resource&gt;</code> element inside a
     <code>&lt;Context&gt;</code> or <code>&lt;DefaultContext&gt;</code>
     element in <code>$CATALINA_HOME/conf/server.xml</code>, and/or for every
     name declared in a <code>&lt;resource-ref&gt;</code> or
     <code>&lt;resource-env-ref&gt;</code> element in the web application
     deployment descriptor, before that resource can be successfully
     accessed.</p>

     <p>Resource parameters are defined by name, and the precise set of
     parameter names supported depend on the resource manager (or object
     factory) you are using - they must match the names of settable JavaBeans
     properties on the corresponding factory class.  The JNDI implementation
     will configure an instance of the specified factory class specified by
     calling all the corresponding JavaBeans property setters, and then
     making the factory instance available via the JNDI <code>lookup()</code>
     call.</p>

     <p>The resource parameters for a JDBC data source might look something
     like this:</p>
 <source>
 &lt;DefaultContext ...&gt;
   ...
   &lt;ResourceParams name="jdbc/EmployeeDB"&gt;
     &lt;parameter&gt;
       &lt;name&gt;driverClassName&lt;/name&gt;
       &lt;value&gt;org.hsql.jdbcDriver&lt;/value&gt;
     &lt;/parameter&gt;
     &lt;parameter&gt;
       &lt;name&gt;driverName&lt;/name&gt;
       &lt;/value&gt;jdbc:HypersonicSQL:database&lt;/value&gt;
     &lt;/parameter&gt;
     &lt;parameter&gt;
       &lt;name&gt;user&lt;/name&gt;
       &lt;value&gt;dbusername&lt;/value&gt;
     &lt;/parameter&gt;
     &lt;parameter&gt;
       &lt;name&gt;password&lt;/name&gt;
       &lt;value&gt;dbpassword&lt;/value&gt;
     &lt;/parameter&gt;
   &lt;/ResourceParams&gt;
   ...
 &lt;/DefaultContext&gt;
 </source>

     <p>If you need to specify the Java class name of a factory class for a
     particular resource type, use a <code>&lt;parameter&gt;</code> entry
     named <code>factory</code> nested inside the
     <code>&lt;ResourceParams&gt;</code> element.</p>

     <p>The valid attributes of a <code>&lt;ResourceParams&gt;</code> element
     are as follows:</p>

     <attributes>

       <attribute name="name" required="true">
         <p>The name of the resource being configured, relative to the
         <code>java:comp/env</code> contxt.  This name <strong>MUST</strong>
         match the name of a resource defined by a <code>&lt;Resource&gt;</code>
         element in <code>$CATALINA_HOME/conf/server.xml</code>, and/or
         referenced in a <code>&lt;resource-ref&gt;</code> or
         <code>&lt;resource-env-ref&gt;</code> element in the web application
         deployment descriptor.</p>
       </attribute>

     </attributes>

   </subsection>


   <subsection name="Resource Links">

      <p>This element is used to create a link to a global JNDI resource. Doing
      a JNDI lookup on the link name will then return the linked global
      resource.</p>

     <p>For example, you can create a resource link like this:</p>
 <source>
 &lt;DefaultContext ...&gt;
   ...
   &lt;ResourceLink name="linkToGlobalResource"
             global="simpleValue"
             type="java.lang.Integer"
   ...
 &lt;/DefaultContext&gt;
 </source>

     <p>The valid attributes for a <code>&lt;ResourceLink&gt;</code> element
     are as follows:</p>

     <attributes>

       <attribute name="global" required="true">
         <p>The name of the linked global resource in the
         gobal JNDI context.</p>
       </attribute>

       <attribute name="name" required="true">
         <p>The name of the resource link to be created, relative to the
         <code>java:comp/env</code> context.</p>
       </attribute>

       <attribute name="type" required="true">
         <p>The fully qualified Java class name expected by the web
         application when it performs a lookup for this resource link.</p>
       </attribute>

     </attributes>

   </subsection>

 </section>


 </body>


 </document>
	<?xml version="1.0"?>
	<!DOCTYPE document [
	<!ENTITY project SYSTEM "project.xml">
	]>
	<document url="defaultcontext.html">

	&project;

	<properties>
	<author email="craigmcc@apache.org">Craig R. McClanahan</author>
	<title>The DefaultContext Component</title>
	</properties>

	<body>


	<section name="Introduction">

	<p>The <strong>DefaultContext</strong> element represents a subset of
	the configuration settings for a <a href="context.html">Context</a>,
	and can be nested inside an <a href="engine.html">Engine</a> or
	<a href="host.html">Host</a> element to represent <em>default
	configuration properties</em> for Contexts that are automatically
	created.</p>

	<p>See <a href="host.html#Automatic Application Deployment">Automatic
	Application Deployment</a> and
	<a href="host.html#User Web Applications">User Web Applications</a>
	for more information about the circumstances in which Catalina will
	automatically create Contexts for you, based on the configuration
	properties that are stored here.</p>

	</section>


	<section name="Attributes">

	<subsection name="Common Attributes">

	<p>All implementations of <strong>Host</strong>
	support the following attributes:</p>

	<attributes>

	<attribute name="cookies" required="false">
	<p>Set to <code>true</code> if you want cookies to be used for
	session identifier communication if supported by the client (this
	is the default). Set to <code>false</code> if you want to disable
	the use of cookies for session identifier communication, and rely
	only on URL rewriting by the application.</p>
	</attribute>

	<attribute name="crossContext" required="false">
	<p>Set to <code>true</code> if you want calls within this application
	to <code>ServletContext.getContext()</code> to successfully return a
	request dispatcher for other web applications running on this virtual
	host. Set to <code>false</code> (the default) in security
	conscious environments, to make <code>getContext()</code> always
	return <code>null</code>.</p>
	</attribute>

	<attribute name="reloadable" required="false">
	<p>Set to <code>true</code> if you want Catalina to monitor classes in
	<code>/WEB-INF/classes/</code> and <code>/WEB-INF/lib</code> for
	changes, and automatically reload the web application if a change
	is detected. This feature is very useful during application
	development, but it requires significant runtime overhead and is
	not recommended for use on deployed production applications. You
	can use the <a href="../manager-howto.html">Manager</a> web
	application, however, to trigger reloads of deployed applications
	on demand.</p>
	</attribute>

	<attribute name="wrapperClass" required="false">
	<p>Java class name of the <code>org.apache.catalina.Wrapper</code>
	implementation class that will be used for servlets managed by this
	Context. If not specified, a standard default value will be used.</p>
	</attribute>

	</attributes>

	</subsection>


	<subsection name="Standard Implementation">

	<p>The standard implementation of <strong>DefaultContext</strong> is
	<strong>org.apache.catalina.core.DefaultContext</strong>.
	It supports the following additional attributes (in addition to the
	common attributes listed above):</p>

	<attributes>

	<attribute name="allowLinking" required="false">
	<p>If the value of this flag is <code>true</code>, symlinks will be
	allowed inside the web application, pointing to resources outside the
	web application base path. If not specified, the default value
	of the flag is <code>false</code>.</p>
	<p><b>NOTE: This flag MUST NOT be set to true on the Windows platform
	(or any other OS which does not have a case sensitive filesystem),
	as it will disable case sensitivity checks, allowing JSP source code
	disclosure, among other security problems.</b></p>
	</attribute>

	<attribute name="cacheMaxSize" required="false">
	<p>Maximum size of the static resource cache in kilobytes.
	If not specified, the default value is <code>10240</code>
	(10 megabytes).</p>
	</attribute>

	<attribute name="cacheTTL" required="false">
	<p>Amount of time in milliseconds between cache entries revalidation.
	If not specified, the default value is <code>5000</code>
	(5 seconds).</p>
	</attribute>

	<attribute name="cachingAllowed" required="false">
	<p>If the value of this flag is <code>true</code>, the cache for static
	resources will be used. If not specified, the default value
	of the flag is <code>true</code>.</p>
	</attribute>

	<attribute name="caseSensitive" required="false">
	<p>If the value of this flag is <code>true</code>, all case sensitivity
	checks will be disabled. If not
	specified, the default value of the flag is <code>true</code>.</p>
	<p><b>NOTE: This flag MUST NOT be set to false on the Windows platform
	(or any other OS which does not have a case sensitive filesystem),
	as it will disable case sensitivity checks, allowing JSP source code
	disclosure, among other security problems.</b></p>
	</attribute>

	<attribute name="managerChecksFrequency" required="false">
	<p>Frequency of the session expiration, and related manager operations.
	Manager operations will be done once for the specified amount of
	backgrondProcess calls (ie, the lower the amount, the most often the
	checks will occur). The minimum value is 1, and the default value is 6.
	</p>
	</attribute>

	<attribute name="swallowOutput" required="false">
	<p>If the value of this flag is <code>true</code>, the bytes output to
	System.out and System.err by the web application will be redirected to
	the web application logger. If not specified, the default value
	of the flag is <code>false</code>.</p>
	</attribute>

	<attribute name="useNaming" required="false">
	<p>Set to <code>true</code> (the default) to have Catalina enable a
	JNDI <code>InitialContext</code> for this web application that is
	compatible with Java2 Enterprise Edition (J2EE) platform
	conventions.</p>
	</attribute>

	</attributes>

	</subsection>


	</section>


	<section name="Nested Components">

	<p>You can nest at most one instance of the following utility components
	by nesting a corresponding element inside your
	<strong>DefaultContext</strong> element:</p>
	<ul>
	<li><a href="loader.html"><strong>Loader</strong></a> -
	Configure the web application class loader that will be used to load
	servlet and bean classes for each web application. Normally, the
	default configuration of the class loader will be sufficient.</li>
	<!--
	<li><a href="logger.html"><strong>Logger</strong></a> -
	Configure a logger that will receive
	and process all log messages for each <strong>Context</strong>. This
	includes application messages logged via calls to
	<code>ServletContext.log()</code>.</li>
	<li><a href="manager.html"><strong>Manager</strong></a> -
	Configure the session manager that will be used to create, destroy,
	and persist HTTP sessions for each web application. Normally, the
	default configuration of the session manager will be sufficient.</li>
	<li><a href="realm.html"><strong>Realm</strong></a> -
	Configure a realm that will allow its
	database of users, and their associated roles, to be utilized solely
	for each particular web application. If not specified, this web
	application will utilize the Realm associated with the owning
	<a href="host.html">Host</a> or <a href="engine.html">Engine</a>.</li>
	<li><a href="resources.html"><strong>Resources</strong></a> -
	Configure the resource manager that will be used to access the static
	resources associated with each web application. Normally, the
	default configuration of the resource manager will be sufficient.</li>
	-->
	</ul>

	</section>


	<section name="Special Features">


	<subsection name="Context Parameters">

	<p>You can configure named values that will be made visible to
	web applications as servlet context initialization parameters by nesting
	<code><Parameter></code> elements inside this element. For
	example, you can create an initialization parameter like this:</p>
	<source>
	<DefaultContext ...>
	...
	<Parameter name="companyName" value="My Company, Incorporated"
	override="false"/>
	...
	</DefaultContext>
	</source>

	<p>This is equivalent to the inclusion of the following element in the
	web application deployment descriptor (<code>/WEB-INF/web.xml</code>):
	</p>
	<source>
	<context-param>
	<param-name>companyName</param-name>
	<param-value>My Company, Incorporated</param-value>
	</context-param>
	</source>
	<p>but does <em>not</em> require modification of the deployment descriptor
	to customize this value.</p>

	<p>The valid attributes for a <code><Parameter></code> element
	are as follows:</p>

	<attributes>

	<attribute name="description" required="false">
	<p>Optional, human-readable description of this context
	initialization parameter.</p>
	</attribute>

	<attribute name="name" required="true">
	<p>The name of the context initialization parameter to be created.</p>
	</attribute>

	<attribute name="override" required="false">
	<p>Set this to <code>false</code> if you do <strong>not</strong> want
	a <code><context-param></code> for the same parameter name,
	found in the web application deployment descriptor, to override the
	value specified here. By default, overrides are allowed.</p>
	</attribute>

	<attribute name="value" required="true">
	<p>The parameter value that will be presented to the application
	when requested by calling
	<code>ServletContext.getInitParameter()</code>.</p>
	</attribute>

	</attributes>

	</subsection>


	<subsection name="Environment Entries">

	<p>You can configure named values that will be made visible to
	web applications as environment entry resources, by nesting
	<code><Environment></code> entries inside this element. For
	example, you can create an environment entry like this:</p>
	<source>
	<DefaultContext ...>
	...
	<Environment name="maxExemptions" value="10"
	type="java.lang.Integer" override="false"/>
	...
	</DefaultContext>
	</source>

	<p>This is equivalent to the inclusion of the following element in the
	web application deployment descriptor (<code>/WEB-INF/web.xml</code>):
	</p>
	<source>
	<env-entry>
	<env-entry-name>maxExemptions</param-name>
	<env-entry-value>10</env-entry-value>
	<env-entry-type>java.lang.Integer</env-entry-type>
	</env-entry>
	</source>
	<p>but does <em>not</em> require modification of the deployment descriptor
	to customize this value.</p>

	<p>The valid attributes for an <code><Environment></code> element
	are as follows:</p>

	<attributes>

	<attribute name="description" required="false">
	<p>Optional, human-readable description of this environment entry.</p>
	</attribute>

	<attribute name="name" required="true">
	<p>The name of the environment entry to be created, relative to the
	<code>java:comp/env</code> context.</p>
	</attribute>

	<attribute name="override" required="false">
	<p>Set this to <code>false</code> if you do <strong>not</strong> want
	an <code><env-entry></code> for the same environment entry name,
	found in the web application deployment descriptor, to override the
	value specified here. By default, overrides are allowed.</p>
	</attribute>

	<attribute name="type" required="true">
	<p>The fully qualified Java class name expected by the web application
	for this environment entry. Must be one of the legal values for
	<code><env-entry-type></code> in the web application deployment
	descriptor: <code>java.lang.Boolean</code>,
	<code>java.lang.Byte</code>, <code>java.lang.Character</code>,
	<code>java.lang.Double</code>, <code>java.lang.Float</code>,
	<code>java.lang.Integer</code>, <code>java.lang.Long</code>,
	<code>java.lang.Short</code>, or <code>java.lang.String</code>.</p>
	</attribute>

	<attribute name="value" required="true">
	<p>The parameter value that will be presented to the application
	when requested from the JNDI context. This value must be convertable
	to the Java type defined by the <code>type</code> attribute.</p>
	</attribute>

	</attributes>

	</subsection>


	<subsection name="Lifecycle Listeners">

	<p>If you have implemented a Java object that needs to know when this
	<strong>Context</strong> is started or stopped, you can declare it by
	nesting a <strong>Listener</strong> element inside this element. The
	class name you specify must implement the
	<code>org.apache.catalina.LifecycleListener</code> interface, and
	it will be notified about the occurrence of the coresponding
	lifecycle events. Configuration of such a listener looks like this:</p>

	<source>
	<DefaultContext ...>
	...
	<Listener className="com.mycompany.mypackage.MyListener" ... >
	...
	</DefaultContext>
	</source>

	<p>Note that a Listener can have any number of additional properties
	that may be configured from this element. Attribute names are matched
	to corresponding JavaBean property names using the standard property
	method naming patterns.</p>

	</subsection>


	<subsection name="Resource Definitions">

	<p>You can declare the characteristics of the resource
	to be returned for JNDI lookups of <code><resource-ref></code> and
	<code><resource-env-ref></code> elements in the web application
	deployment descriptor. You <strong>MUST</strong> also define
	<a href="#Resource Parameters">Resource Parameters</a>
	for the same resource name, to configure
	the object factory to be used (if not known to Tomcat already), and
	the properties used to configure that object factory.</p>

	<p>For example, you can create a resource definition like this:</p>
	<source>
	<DefaultContext ...>
	...
	<Resource name="jdbc/EmployeeDB" auth="Container"
	type="javax.sql.DataSource"
	description="Employees Database for HR Applications"/>
	...
	</DefaultContext>
	</source>

	<p>This is equivalent to the inclusion of the following element in the
	web application deployment descriptor (<code>/WEB-INF/web.xml</code>):</p>
	<source>
	<resource-ref>
	<description>Employees Database for HR Applications</description>
	<res-ref-name>jdbc/EmployeeDB</res-ref-name>
	<res-ref-type>javax.sql.DataSource</res-ref-type>
	<res-auth>Container</res-auth>
	</resource-ref>
	</source>

	<p>but does <em>not</em> require modification of the deployment
	descriptor to customize this value.</p>

	<p>The valid attriutes for a <code><Resource></code> element
	are as follows:</p>

	<attributes>

	<attribute name="auth" required="false">
	<p>Specify whether the web Application code signs on to the
	corresponding resource manager programatically, or whether the
	Container will sign on to the resource manager on behalf of the
	application. The value of this attribute must be
	<code>Application</code> or <code>Container</code>. This
	attribute is <strong>required</strong> if the web application
	will use a <code><resource-ref></code> element in the web
	application deployment descriptor, but is optional if the
	application uses a <code><resource-env-ref></code> instead.</p>
	</attribute>

	<attribute name="description" required="false">
	<p>Optional, human-readable description of this resource.</p>
	</attribute>

	<attribute name="name" required="true">
	<p>The name of the resource to be created, relative to the
	<code>java:comp/env</code> context.</p>
	</attribute>

	<attribute name="scope" required="false">
	<p>Specify whether connections obtained through this resource
	manager can be shared. The value of this attribute must be
	<code>Shareable</code> or <code>Unshareable</code>. By default,
	connections are assumed to be shareable.</p>
	</attribute>

	<attribute name="type" required="true">
	<p>The fully qualified Java class name expected by the web
	application when it performs a lookup for this resource.</p>
	</attribute>

	</attributes>


	</subsection>


	<subsection name="Resource Parameters">

	<p>This element is used to configure the resource manager (or object
	factory) used to return objects when the web application performs a
	JNDI lookup operation on the corresponding resource name. You
	<strong>MUST</strong> define resource parameters for every resource name
	that is specified by a <code><Resource></code> element inside a
	<code><Context></code> or <code><DefaultContext></code>
	element in <code>$CATALINA_HOME/conf/server.xml</code>, and/or for every
	name declared in a <code><resource-ref></code> or
	<code><resource-env-ref></code> element in the web application
	deployment descriptor, before that resource can be successfully
	accessed.</p>

	<p>Resource parameters are defined by name, and the precise set of
	parameter names supported depend on the resource manager (or object
	factory) you are using - they must match the names of settable JavaBeans
	properties on the corresponding factory class. The JNDI implementation
	will configure an instance of the specified factory class specified by
	calling all the corresponding JavaBeans property setters, and then
	making the factory instance available via the JNDI <code>lookup()</code>
	call.</p>

	<p>The resource parameters for a JDBC data source might look something
	like this:</p>
	<source>
	<DefaultContext ...>
	...
	<ResourceParams name="jdbc/EmployeeDB">
	<parameter>
	<name>driverClassName</name>
	<value>org.hsql.jdbcDriver</value>
	</parameter>
	<parameter>
	<name>driverName</name>
	</value>jdbc:HypersonicSQL:database</value>
	</parameter>
	<parameter>
	<name>user</name>
	<value>dbusername</value>
	</parameter>
	<parameter>
	<name>password</name>
	<value>dbpassword</value>
	</parameter>
	</ResourceParams>
	...
	</DefaultContext>
	</source>

	<p>If you need to specify the Java class name of a factory class for a
	particular resource type, use a <code><parameter></code> entry
	named <code>factory</code> nested inside the
	<code><ResourceParams></code> element.</p>

	<p>The valid attributes of a <code><ResourceParams></code> element
	are as follows:</p>

	<attributes>

	<attribute name="name" required="true">
	<p>The name of the resource being configured, relative to the
	<code>java:comp/env</code> contxt. This name <strong>MUST</strong>
	match the name of a resource defined by a <code><Resource></code>
	element in <code>$CATALINA_HOME/conf/server.xml</code>, and/or
	referenced in a <code><resource-ref></code> or
	<code><resource-env-ref></code> element in the web application
	deployment descriptor.</p>
	</attribute>

	</attributes>

	</subsection>


	<subsection name="Resource Links">

	<p>This element is used to create a link to a global JNDI resource. Doing
	a JNDI lookup on the link name will then return the linked global
	resource.</p>

	<p>For example, you can create a resource link like this:</p>
	<source>
	<DefaultContext ...>
	...
	<ResourceLink name="linkToGlobalResource"
	global="simpleValue"
	type="java.lang.Integer"
	...
	</DefaultContext>
	</source>

	<p>The valid attributes for a <code><ResourceLink></code> element
	are as follows:</p>

	<attributes>

	<attribute name="global" required="true">
	<p>The name of the linked global resource in the
	gobal JNDI context.</p>
	</attribute>

	<attribute name="name" required="true">
	<p>The name of the resource link to be created, relative to the
	<code>java:comp/env</code> context.</p>
	</attribute>

	<attribute name="type" required="true">
	<p>The fully qualified Java class name expected by the web
	application when it performs a lookup for this resource link.</p>
	</attribute>

	</attributes>

	</subsection>

	</section>


	</body>


	</document>