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markt pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/tomcat.git
The following commit(s) were added to refs/heads/main by this push:
new 68c92190b0 Use new EL 6.1 marker class for this optimisation
68c92190b0 is described below
commit 68c92190b05b137f47ff3a6f93e47dee04a312b1
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Tue May 13 09:51:06 2025 +0100
Use new EL 6.1 marker class for this optimisation
---
java/jakarta/el/ELResolver.java | 19 +++++++++++++
java/jakarta/servlet/jsp/el/ImportELResolver.java | 33 ++++++-----------------
java/org/apache/el/parser/AstIdentifier.java | 9 +++----
webapps/docs/changelog.xml | 6 +++++
4 files changed, 37 insertions(+), 30 deletions(-)
diff --git a/java/jakarta/el/ELResolver.java b/java/jakarta/el/ELResolver.java
index 0b9be0327a..d650069cb0 100644
--- a/java/jakarta/el/ELResolver.java
+++ b/java/jakarta/el/ELResolver.java
@@ -133,4 +133,23 @@ public abstract class ELResolver {
context.setPropertyResolved(false);
return null;
}
+
+ /**
+ * This class is used as a key for {@link ELContext#getContext(Class)}.
The key references a context object that if
+ * present and set to {@code Boolean#TRUE}, indicates that the identifier
being resolved is a single, stand-alone
+ * identifier. This allows {@link ELResolver} instances - and in particular
+ * {@code jakarta.servlet.jsp.el.ImportELResolver} - to optimise the
resolution of the identifier and avoid
+ * unnecessary and expensive class loader lookups.
+ * <p>
+ * The EL implementation is required to set this key with the value {@code
Boolean#TRUE} when resolving a single,
+ * stand-alone identifier.
+ *
+ * @since Jakarta Expression Language 6.1
+ */
+ public class StandaloneIdentifierMarker {
+
+ private StandaloneIdentifierMarker() {
+ // Non-public default constructor as there is no need to create
instances of this class.
+ }
+ }
}
diff --git a/java/jakarta/servlet/jsp/el/ImportELResolver.java
b/java/jakarta/servlet/jsp/el/ImportELResolver.java
index eb3746bbce..3b003c3a12 100644
--- a/java/jakarta/servlet/jsp/el/ImportELResolver.java
+++ b/java/jakarta/servlet/jsp/el/ImportELResolver.java
@@ -30,20 +30,6 @@ import jakarta.el.ImportHandler;
*/
public class ImportELResolver 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;
- }
-
/**
* Default constructor.
*/
@@ -60,17 +46,14 @@ public class ImportELResolver extends ELResolver {
if (base == null) {
if (property != 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;
- }
+ /*
+ * The EL implementation 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(ELResolver.StandaloneIdentifierMarker.class);
+ if (value != null && value.booleanValue()) {
+ resolveClass = false;
}
ImportHandler importHandler = context.getImportHandler();
diff --git a/java/org/apache/el/parser/AstIdentifier.java
b/java/org/apache/el/parser/AstIdentifier.java
index a1f9759932..63b6e89e7a 100644
--- a/java/org/apache/el/parser/AstIdentifier.java
+++ b/java/org/apache/el/parser/AstIdentifier.java
@@ -19,6 +19,7 @@ package org.apache.el.parser;
import jakarta.el.ELClass;
import jakarta.el.ELException;
+import jakarta.el.ELResolver;
import jakarta.el.MethodExpression;
import jakarta.el.MethodInfo;
import jakarta.el.MethodNotFoundException;
@@ -78,15 +79,13 @@ public final class AstIdentifier extends SimpleNode {
ctx.setPropertyResolved(false);
Object result;
/*
- * Putting the Boolean into the ELContext is part of a performance
optimisation for ScopedAttributeELResolver.
+ * Putting the Boolean into the ELContext is part of a performance
optimisation for ImportELResolver.
* 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);
+ if (!(parent instanceof AstValue)) {
+ ctx.putContext(ELResolver.StandaloneIdentifierMarker.class,
Boolean.TRUE);
}
try {
result = ctx.getELResolver().getValue(ctx, null, this.image);
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index c4a2380c74..4cc9bf852b 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -193,6 +193,12 @@
<code>compilerTargetVM</code> have been updated to 21 to align with
Java
21 being the minimum Java version required for Tomcat 12. (markt)
</update>
+ <scode>
+ Refactor the performance optimisation for
+ <code>jakarta.servlet.jsp.el.ImportELResolver</code> to use the new
+ marker class,
+ <code>jakarta.el.ELResolver.StandaloneIdentifierMarker</code>. (markt)
+ </scode>
<!-- Entries for backport and removal before 12.0.0-M1 below this line
-->
</changelog>
</subsection>
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