Author: markt
Date: Thu Mar 10 14:22:51 2016
New Revision: 1734418
URL: http://svn.apache.org/viewvc?rev=1734418&view=rev
Log:
Fix https://bz.apache.org/bugzilla/show_bug.cgi?id=57583
Improve long standing performance issue with EL and undefined attributes.
Modified:
tomcat/trunk/java/javax/servlet/jsp/el/ScopedAttributeELResolver.java
tomcat/trunk/java/org/apache/el/parser/AstIdentifier.java
tomcat/trunk/webapps/docs/changelog.xml
Modified: tomcat/trunk/java/javax/servlet/jsp/el/ScopedAttributeELResolver.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/javax/servlet/jsp/el/ScopedAttributeELResolver.java?rev=1734418&r1=1734417&r2=1734418&view=diff
==============================================================================
--- tomcat/trunk/java/javax/servlet/jsp/el/ScopedAttributeELResolver.java
(original)
+++ tomcat/trunk/java/javax/servlet/jsp/el/ScopedAttributeELResolver.java Thu
Mar 10 14:22:51 2016
@@ -35,6 +35,20 @@ import javax.servlet.jsp.PageContext;
*/
public class ScopedAttributeELResolver extends ELResolver {
+ // Indicates if a performance short-cut is available
+ private static final Class<?> AST_IDENTIFIER_KEY;
+
+ static {
+ Class<?> key = null;
+ try {
+ key = Class.forName("org.apache.el.parser.AstIdentifier");
+ } catch (Exception e) {
+ // Ignore: Expected if not running on Tomcat. Not a problem since
+ // this just allows a short-cut.
+ }
+ AST_IDENTIFIER_KEY = key;
+ }
+
@Override
public Object getValue(ELContext context, Object base, Object property) {
if (context == null) {
@@ -51,10 +65,26 @@ public class ScopedAttributeELResolver e
result = page.findAttribute(key);
if (result == null) {
+ boolean resolveClass = true;
+ // Performance short-cut available when running on Tomcat
+ if (AST_IDENTIFIER_KEY != null) {
+ // Tomcat will set this key to Boolean.TRUE if the
+ // identifier is a stand-alone identifier (i.e.
+ // identifier) rather than part of an AstValue (i.e.
+ // identifier.something). Imports do not need to be
+ // checked if this is a stand-alone identifier
+ Boolean value = (Boolean)
context.getContext(AST_IDENTIFIER_KEY);
+ if (value != null && value.booleanValue()) {
+ resolveClass = false;
+ }
+ }
// This might be the name of an imported class
ImportHandler importHandler = context.getImportHandler();
if (importHandler != null) {
- Class<?> clazz = importHandler.resolveClass(key);
+ Class<?> clazz = null;
+ if (resolveClass) {
+ clazz = importHandler.resolveClass(key);
+ }
if (clazz != null) {
result = new ELClass(clazz);
}
Modified: tomcat/trunk/java/org/apache/el/parser/AstIdentifier.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/el/parser/AstIdentifier.java?rev=1734418&r1=1734417&r2=1734418&view=diff
==============================================================================
--- tomcat/trunk/java/org/apache/el/parser/AstIdentifier.java (original)
+++ tomcat/trunk/java/org/apache/el/parser/AstIdentifier.java Thu Mar 10
14:22:51 2016
@@ -77,7 +77,27 @@ public final class AstIdentifier extends
// EL Resolvers
ctx.setPropertyResolved(false);
- Object result = ctx.getELResolver().getValue(ctx, null, this.image);
+ Object result;
+ /* Putting the Boolean into the ELContext is part of a performance
+ * optimisation for ScopedAttributeELResolver. When looking up "foo",
+ * the resolver can't differentiate between ${ foo } and ${ foo.bar }.
+ * This is important because the expensive class lookup only needs to
+ * be performed in the later case. This flag tells the resolver if the
+ * lookup can be skipped.
+ */
+ if (parent instanceof AstValue) {
+ ctx.putContext(this.getClass(), Boolean.FALSE);
+ } else {
+ ctx.putContext(this.getClass(), Boolean.TRUE);
+ }
+ try {
+ result = ctx.getELResolver().getValue(ctx, null, this.image);
+ } finally {
+ // Always reset the flag to false so the optimisation is not
applied
+ // inappropriately
+ ctx.putContext(this.getClass(), Boolean.FALSE);
+ }
+
if (ctx.isPropertyResolved()) {
return result;
}
Modified: tomcat/trunk/webapps/docs/changelog.xml
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/docs/changelog.xml?rev=1734418&r1=1734417&r2=1734418&view=diff
==============================================================================
--- tomcat/trunk/webapps/docs/changelog.xml (original)
+++ tomcat/trunk/webapps/docs/changelog.xml Thu Mar 10 14:22:51 2016
@@ -222,6 +222,12 @@
<update>
Update to the Eclipse JDT Compiler 4.5.1. (markt)
</update>
+ <fix>
+ <bug>57583</bug>: Improve the performance of
+ <code>javax.servlet.jsp.el.ScopedAttributeELResolver</code> when
+ resolving attributes that do not exist. This improvement only works
when
+ Jasper is used with with Tomcat's EL implementation. (markt)
+ </fix>
</changelog>
</subsection>
<subsection name="WebSocket">
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