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<!DOCTYPE document [
<!ENTITY project SYSTEM "project.xml">
]>
<document url="sessionidgenerator.html">
&project;
<properties>
<title>The SessionIdGenerator Component</title>
</properties>
<body>
<section name="Table of Contents">
<toc/>
</section>
<section name="Introduction">
<p>The <strong>SessionIdGenerator</strong> element represents the <em>session
id generator</em> that will be used to create session ids used by
web application HTTP sessions.</p>
<p>A SessionIdGenerator element MAY be nested inside a
<a href="manager.html">Manager</a> component. If it is not included,
a default SessionIdGenerator configuration will be created automatically, which
is sufficient for most requirements, — see
<em>Standard SessionIdGenerator Implementation</em> below for the details
of this configuration.</p>
</section>
<section name="Attributes">
<subsection name="Common Attributes">
<p>All implementations of <strong>SessionIdGenerator</strong>
support the following attributes:</p>
<attributes>
<attribute name="className" required="false">
<p>Java class name of the implementation to use. This class must
implement the <code>org.apache.catalina.SessionIdGenerator</code> interface.
If not specified, the standard value (defined below) will be used.</p>
</attribute>
<attribute name="jvmRoute" required="false">
<p>A routing identifier for this Tomcat instance. It will be added
to the session id to allow for stateless stickiness routing by
load balancers. The details on how the <code>jvmRoute</code>
will be included in the id are implementation dependent.
See <a href="#Standard_Implementation">Standard Implementation</a>
for the default behavior.</p>
<p><strong>NOTE</strong> - The value for this property is inherited
automatically from the <code>jvmRoute</code> attribute of the
<a href="engine.html">Engine</a> element.</p>
</attribute>
<attribute name="sessionIdLength" required="false">
<p>The length of session ids created by this SessionIdGenerator.
The details on how the <code>sessionIdLength</code>
influences the session id length are implementation dependent.
See <a href="#Standard_Implementation">Standard Implementation</a>
for the default behavior.</p>
</attribute>
</attributes>
</subsection>
<subsection name="Standard Implementation">
<p>Tomcat provides a standard implementations of <strong>SessionIdGenerator</strong>
for use.</p>
<h3>Standard SessionIdGenerator Implementation</h3>
<p>The standard implementation of <strong>SessionIdGenerator</strong> is
<strong>org.apache.catalina.util.StandardSessionIdGenerator</strong>.
It supports the following attributes:</p>
<attributes>
<attribute name="jvmRoute" required="false">
<p>A routing identifier for this Tomcat instance. It will be added
to the end of the session id separated by a ".".</p>
</attribute>
<attribute name="sessionIdLength" required="false">
<p>The length of session ids created by this SessionIdGenerator.
More precisely the session id length is twice the value of
<code>sessionIdLength</code> plus the length of the trailing
<code>jvmRoute</code> if given. The factor 2 is because
the session id is constructed using <code>sessionIdLength</code>
random bytes, each byte being encoded in two hex characters
in the actual id. The default value is 16.</p>
</attribute>
</attributes>
</subsection>
</section>
</body>
</document>