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From ma...@apache.org
Subject svn commit: r1670298 - in /tomcat/site/trunk: docs/migration-8.html xdocs/migration-8.xml
Date Tue, 31 Mar 2015 10:16:47 GMT
Author: markt
Date: Tue Mar 31 10:16:46 2015
New Revision: 1670298

URL: http://svn.apache.org/r1670298
Log:
https://bz.apache.org/bugzilla/show_bug.cgi?id=57773
Add information on the potential performance issue when using undefined identifiers.

Modified:
    tomcat/site/trunk/docs/migration-8.html
    tomcat/site/trunk/xdocs/migration-8.xml

Modified: tomcat/site/trunk/docs/migration-8.html
URL: http://svn.apache.org/viewvc/tomcat/site/trunk/docs/migration-8.html?rev=1670298&r1=1670297&r2=1670298&view=diff
==============================================================================
--- tomcat/site/trunk/docs/migration-8.html (original)
+++ tomcat/site/trunk/docs/migration-8.html Tue Mar 31 10:16:46 2015
@@ -215,6 +215,9 @@
 <a href="#Servlet_3.1_API">Servlet 3.1 API</a>
 </li>
 <li>
+<a href="#JavaServer_Pages_2.3">JavaServer Pages 2.3</a>
+</li>
+<li>
 <a href="#Default_connector_implementation">Default connector implementation</a>
 </li>
 <li>
@@ -327,6 +330,48 @@ of Apache Tomcat.</p>
 
   
 </div>
+</div>
+
+  
+<div class="subsection">
+<h4 id="JavaServer_Pages_2.3">JavaServer Pages 2.3</h4>
+<div class="text">
+  
+    
+<p>Unified Expression Language 3.0 added support for referencing static
+    fields and methods. Supporting this feature in JSPs required changing the
+    <code>javax.servlet.jsp.el.ScopedAttributeELResolver</code> implementation
+    so that it also checked identifiers to see if they were names of imported
+    classes or fields. In some circumstances, this change triggers significant
+    slow down. This affects identifiers that may refer to a page, request,
+    session or application scoped variable or may be undefined. When undefined,
+    it takes significantly longer to resolve the identifier since it is now also
+    checked to see if it is an imported class or field. To avoid this slow down,
+    code such as:</p>
+
+    
+<div class="codeBox">
+<pre>
+<code>${undefined}</code>
+</pre>
+</div>
+
+    
+<p>should be replaced with:</p>
+    
+    
+<div class="codeBox">
+<pre>
+<code>${requestScope.undefined}</code>
+</pre>
+</div>
+    
+    
+<p>or similar, using the appropriate scope for where the variable is
+    defined.</p>
+
+  
+</div>
 </div>
 
   

Modified: tomcat/site/trunk/xdocs/migration-8.xml
URL: http://svn.apache.org/viewvc/tomcat/site/trunk/xdocs/migration-8.xml?rev=1670298&r1=1670297&r2=1670298&view=diff
==============================================================================
--- tomcat/site/trunk/xdocs/migration-8.xml (original)
+++ tomcat/site/trunk/xdocs/migration-8.xml Tue Mar 31 10:16:46 2015
@@ -62,6 +62,30 @@ of Apache Tomcat.</p>
 
   </subsection>
 
+  <subsection name="JavaServer Pages 2.3">
+  
+    <p>Unified Expression Language 3.0 added support for referencing static
+    fields and methods. Supporting this feature in JSPs required changing the
+    <code>javax.servlet.jsp.el.ScopedAttributeELResolver</code> implementation
+    so that it also checked identifiers to see if they were names of imported
+    classes or fields. In some circumstances, this change triggers significant
+    slow down. This affects identifiers that may refer to a page, request,
+    session or application scoped variable or may be undefined. When undefined,
+    it takes significantly longer to resolve the identifier since it is now also
+    checked to see if it is an imported class or field. To avoid this slow down,
+    code such as:</p>
+
+    <source><![CDATA[${undefined}]]></source>
+
+    <p>should be replaced with:</p>
+    
+    <source><![CDATA[${requestScope.undefined}]]></source>
+    
+    <p>or similar, using the appropriate scope for where the variable is
+    defined.</p>
+
+  </subsection>
+
   <subsection name="Default connector implementation">
 
     <p>The default HTTP and AJP connector implementation has switched from the



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