Hello to everyone
I have discovered two problems while using AspectJ in my web application for
logging and performance metering. Please, let me know if they are relevant
to that mailing list or I should create a bug report or point me to the
solution.
My web application uses Spring but I do not use their weaving helpers except
for one class because I need to weave not just beans but servlets and and
other non-bean classes.
My configuration is simple and straightforward:
*aop.xml*:
<aspectj>
<weaver options="-verbose -showWeaveInfo">
<!-- only weave classes in our application-specific packages -->
<include within="net.mansion..*"/>
</weaver>
<aspects>
<!-- weave in just this aspect -->
<aspect name="net.mansion.logging.LoggingAspect"/>
</aspects>
</aspectj>
*context.xml.default*:
<Loader
loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"
useSystemClassLoaderAsParent="false" />
code snippet of my *LoggingAspect* class with annotation:
@Around(... + // a lot of other pointcuts
" || execution(public void
net.mansion.redirect.impl.engine.web.RedirectProcessorServlet.doGet(javax.servlet.http.HttpServletRequest,
javax.servlet.http.HttpServletResponse))" )
public Object debugMethodLogging(ProceedingJoinPoint joinPoint) throws
Throwable {
return debugMethodLogging(Level.DEBUG, joinPoint);
}
*logging.properties*:
handlers= java.util.logging.FileHandler
.level= TRACE
java.util.logging.FileHandler.pattern = D:/logs/aspectj.log
java.util.logging.FileHandler.count = 1
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter
java.util.logging.FileHandler.level = FINER
org.aspectj.level = FINER
*Problem 1*: What I have found is that aspect is not applied to my servlet
classes. While debugging the AspectJ I discovered that there are racing
conditions in Aj.java when I run application under Tomcat. WeavingAdaptor
initialization has not been complete yet (see line 254) when Tomcat loads
servlet classes using *TomcatInstrumentableClassLoader*. Thought there are
synchronized section but it only ensures that only one instance per
classloader will be created. While WeavingAdaptor is not initialized yet and
ClassLoaderWeavingAdaptor's field enabled is false that prevents class from
being weaved:
WeavingAdaptor.java (line 294):
if (!enabled) {
if (trace.isTraceEnabled()) {
trace.exit("weaveClass", false);
}
return bytes;
}
23.06.2010 18:45:16 org.aspectj.weaver.loadtime.Aj preProcess
FINER: EVENT
23.06.2010 18:45:16 org.aspectj.weaver.tools.WeavingAdaptor weaveClass
FINER: ENTRY org.aspectj.weaver.loadtime.classloaderweavingadap...@1d0740e
23.06.2010 18:45:16 org.aspectj.weaver.tools.WeavingAdaptor weaveClass
FINER: ENTRY
net/mansion/redirect/impl/engine/web/RedirectProcessorServlet/class
byte[12079]
23.06.2010 18:45:16 org.aspectj.weaver.tools.WeavingAdaptor weaveClass
FINER: RETURN *false*
**
In AspectJ output to stdout there is no messages like "weaving [class name]"
or "not weaving [class name]" that could said that class is processed with
weaver (no servlet classes mentioned at all).
When initialize method of ClassLoaderWeavingAdaptor is complete, I see that
messages but for other classes of my application.
Has any one run into this issue before?
Problem 2: I have tons of ClassNotFoundException in aspectj log for all the
classes that are weaved (1-40 exceptions for the single class):
SEVERE: Unable to find class
'*java.lang.*net.mansion.redirect.impl.engine.web.RedirectProcessorServlet'
in repository
java.lang.ClassNotFoundException:
*java.lang*.net.mansion.redirect.impl.engine.web.RedirectProcessorServlet
not found - unable to determine URL
at
org.aspectj.apache.bcel.util.ClassLoaderRepository.loadClass(ClassLoaderRepository.java:292)
at org.aspectj.weaver.bcel.BcelWorld.lookupJavaClass(BcelWorld.java:390)
at org.aspectj.weaver.bcel.BcelWorld.resolveDelegate(BcelWorld.java:373)
at org.aspectj.weaver.ltw.LTWWorld.resolveDelegate(LTWWorld.java:111)
at org.aspectj.weaver.World.resolveToReferenceType(World.java:440)
at org.aspectj.weaver.World.resolve(World.java:296)
at org.aspectj.weaver.patterns.SimpleScope.lookupType(SimpleScope.java:59)
at org.aspectj.weaver.BindingScope.lookupType(BindingScope.java:55)
at
org.aspectj.weaver.patterns.WildTypePattern.lookupTypeInScope(WildTypePattern
Classes are under classpath and loaded with correct classloader. I know that
I am not the first one who saw that messages. The problem as I think resides
in *org.aspectj.weaver.patterns.WildTypePattern* and *
org.aspectj.weaver.patterns.SimpleScope* classes. More pecisely in method
lookupType:
public UnresolvedType lookupType(String name, IHasPosition location) {
for (int i = 0; i < importedNames.length; i++) {
String importedName = importedNames[i];
// // make sure we're matching against the
// // type name rather than part of it
// if (importedName.endsWith("." + name)) {
if (importedName.endsWith(name)) {
return world.resolve(importedName);
}
}
for (int i = 0; i < importedPrefixes.length; i++) {
String importedPrefix = importedPrefixes[i];
ResolvedType tryType =
world.resolve(UnresolvedType.forName(importedPrefix + name), true);
if (!tryType.isMissing()) {
return tryType;
}
}
return world.resolve(UnresolvedType.forName(name), true); // my comment
name here is "net.mansion.redirect.impl.engine.web.RedirectProcessorServlet"
}
I not know why it was decided that imported types has priority over
specifyied in annotations (like
net.mansion.redirect.impl.engine.web.RedirectProcessorServlet), but this
methods tries first to find in scope classes with java.lang prefix and a
bunch of other prefixes specific for application. In my case importedPrefixes
array was of size 40 and looks like:
importedPrefixes[0] = 'java.lang'
importedPrefixes[1] = 'net.mansion.logging'
importedPrefixes[2] = 'net.mansion.logging'
...
importedPrefixes[39] = 'net.mansion.logging'
Note that in my case there were 39 of completely identical entries in the
array. Of course there is no classes in java.lang.net.mansion.redirect
package and net.mansion.logging.net.mansion.redirect package as well. It
spends significant time while trying to load non-existing classes (I have 22
MB log file consisting mostly from ClassNotFoundException errors).
Actual type is correctly resolved at the return statement:
world.resolve(UnresolvedType.forName(name),
true).
Turning off the bcel caching does not solve the problem.
Has anyone an idea how to fix that all? I have aready spent 3 days on that
stuff :-(
P.S. How to download latest build? It says "access denied" when I try to get
the archive:
http://www.eclipse.org/downloads/download.php?file=/tools/aspectj/aspectj-1.6.9.RC1.jar&mirror_id=999&url=http://d2u376ub0heus3.cloudfront.net/tools/aspectj/aspectj-1.6.9.RC1.jar
regards,
Peter
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