Hi Alexander,
Thank you for your detailed review and explanation. Really appreciate your
effort and time into this. And thank you for showing how to write
good-quality code.
There are several things that I want to clarify.
1.
I made a mistake copying code and renaming stuff from my code base.
Thanks for pointing it out. Instead of using a HashMap<java.lang.Class,
ThreadLocal>, a ConcurrentHashMap<java.lang.Class, ThreadLocal> should be
used.
2.
id_assigned guard
Thanks for pointing out that “after returning” advice works for nested
constructors like this(11). I removed it.
3.
ThreadLocal
From my understanding, ThreadLocal is a ConcurrentHashMap whose key is
Thread and value is the object inside ThreadLocal.
I think I didn’t make it clear. Using ThreadLocal means that I’m
actually using *(ThreadID and MyID)* combined as the ID. And I ignored
that ThreadID could be reused because I’m targeting for thread pools that
use long-live threads. My current project requires my instrumentation to
minimize introduction of any resource contention, so I tried to minimize
introduced synchronization in this way.
Using ConcurrentHashMap without proper synchronization doesn’t work, but
using ConcurrentHashMap<XXX, ThreadLocal> with minimum synchronization
(i.e., only synchronize when initializing the ThreadLocal - double check
luckily works) does work. I put a test that could be compiled and executed
here.
Test that shows it works
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
public class ConcurrentErrorTest {
public static Map<MyClass, ThreadLocal<Long>> counters = new
ConcurrentHashMap<MyClass, ThreadLocal<Long>>();
public static long getMyCounter(MyClass clazz) {
ThreadLocal<Long> local = counters.get(clazz);
if (local == null) {
// need to initialize the ThreadLocal
// This is the only place that needs synchronization.
synchronized (clazz) { // synchronize on the given clazz is enough
// Double check to avoid multi threads entered the previous if statement
if (local == null) {
local = new ThreadLocal<Long>() {
@Override
protected Long initialValue() {
return (long) 0;
}
};
counters.put(clazz, local);
}
}
}
return (long) local.get();
}
private static void setMyCounter(MyClass clazz, long counter) {
ThreadLocal<Long> local = counters.get(clazz);
// This function is only called in incrementMyCounter() so it's not null.
assert local != null;
local.remove();
local.set(counter);
}
public static void incrementMyCounter(MyClass clazz) {
setMyCounter(clazz, getMyCounter(clazz)+1);
}
private static final java.util.Random RANDOM = new java.util.Random();
// passed this unsafe test, but it takes a long time, please change
ConcurrentErrorTest.limit = 100 before testing with this method.
public static void incrementMyCounterUnsafe(MyClass clazz)
throws InterruptedException {
long counter = getMyCounter(clazz);
try {
Thread.sleep(RANDOM.nextInt(10));
} catch (InterruptedException e) {
throw e;
}
setMyCounter(clazz, counter + 1);
}
static final AtomicInteger errCount = new AtomicInteger();
static final int numThreads = 10;
static final int limit = 1000;
// Mimic java.lang.Class<?> objects
private static List<MyClass> keys;
static {
keys = new ArrayList<MyClass>();
for (int j = 0; j < limit; j++) {
keys.add(new MyClass(j));
}
}
private static class MyClass {
private int id;
public MyClass(int id) {
this.id = id;
}
@Override
public String toString() {
return Integer.toString(id);
}
}
public static void main(String[] args) throws InterruptedException
{
long startTime = System.currentTimeMillis();
List<Thread> threads = new LinkedList<Thread>();
for (int i = 0; i < numThreads; i++)
{
Thread t = getThread();
threads.add(t);
t.start();
}
for (int i = 0; i < numThreads; i++)
{
threads.get(i).join();
}
System.out.println("Length:" + counters.size());
System.out.println("Errors recorded: " + errCount.get());
long stopTime = System.currentTimeMillis();
long elapsedTime = stopTime - startTime;
System.out.println(elapsedTime);
}
private static Thread getThread()
{
return new Thread(new Runnable() {
public void run()
{
try
{
for (MyClass key : keys) {
for (int i = 0; i < limit; i++) {
getMyCounter(key);
incrementMyCounter(key);
}
}
}
catch (Exception e)
{
System.out.println("P - Error occured: " + e.toString());
e.printStackTrace();
errCount.incrementAndGet();
}
}
});
}
}
Running it on my laptop costs 392 milliseconds. I also tested using your
method (replace the map and getter and incrementor function as follows), it
took 1566 milliseconds.
private static final Map<MyClass, Long> counters =
new ConcurrentHashMap<MyClass, Long>();
public static synchronized long getMyCounter(MyClass clazz) {
Long counter = counters.get(clazz);
return counter == null ? 0 : counter;
}
private static synchronized void incrementMyCounter(MyClass clazz) {
counters.put(clazz, getMyCounter(clazz) + 1);
}
Extra synchronization needed in your method
In the constructor, an extra synchronization is needed (without this
synchronization, the incrementation would be correct, but 2
InstrumentedRunnableCallable could get the same ID):
after() returning(InstrumentedRunnableCallable runnableCallable) :
call(InstrumentedRunnableCallable+.new(..))
{
runnableCallable.setCreatorTID(currentThread().getId());
// without this synchronization, the incrementation would be correct,
// but 2 InstrumentedRunnableCallable could get the same ID.
synchronized(instanceCounters) {
runnableCallable.setId(getInstanceCounter(runnableCallable.getClass()));
incrementInstanceCounter(runnableCallable.getClass());
}
// Use this instead in order to mess up instance counters
//incrementInstanceCounterThreadUnsafe(runnableCallable.getClass());
printLogMessage("[Create Runnable/Callable]", runnableCallable);
}
After fixing bugs and refactoring for my previous aspect
- Change the HashMap to ConcurrentHashMap
- Removed _id_assigned guard.
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.lang.Runnable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Future;
privileged aspect RunnablesCallables {
public static Map<java.lang.Class, ThreadLocal<Long<>()>> _counters = new
ConcurrentHashMap();
public static long getCounter(java.lang.Class clazz) {
ThreadLocal<Long> local = _counters.get(clazz);
if (local == null) { // need to initialize the ThreadLocal
synchronized (clazz) { // synchronize on the given clazz is enough
// Check again to avoid multi threads entered the previous if statement
if (local == null) {
local = new ThreadLocal<Long>() {
@Override
protected Long initialValue() {
return (long) 0;
}
};
_counters.put(clazz, local);
}
}
}
return (long) local.get();
}
private static void setCounter(java.lang.Class clazz, long counter) {
ThreadLocal<Long> local = _counters.get(clazz);
local.remove();
local.set(counter);
}
public static void incrementCounter(java.lang.Class clazz) {
setCounter(clazz, getCounter(clazz)+1);
}
public interface InstrumentedRunnableCallable {}
private long InstrumentedRunnableCallable._id = -1;
// Java could reuse thread ID. Ignored for now since we target
thread pool that use long-live threads.
// Records which thread created this Object.
private long InstrumentedRunnableCallable._creator_tid = -1;
public long InstrumentedRunnableCallable.getId() {
return _id;
}
public void InstrumentedRunnableCallable.setId(long id) {
_id = id;
}
public long InstrumentedRunnableCallable.getCreatorTid() {
return _creator_tid;
}
public void InstrumentedRunnableCallable.setCreatorTid(long id) {
_creator_tid = id;
}
declare parents: (Runnable)+ implements InstrumentedRunnableCallable;
declare parents: (Callable)+ implements InstrumentedRunnableCallable;
after() returning(InstrumentedRunnableCallable r):
(call(InstrumentedRunnableCallable+.new(..))) {
r.setCreatorTid(Thread.currentThread().getId());
r.setId(RunnablesCallables.getCounter(r.getClass()));
RunnablesCallables.incrementCounter(r.getClass());
}
Object around(InstrumentedRunnableCallable runnableCallable):
this(runnableCallable) &&
(execution(void Runnable+.run(..)) || execution(* Callable+.call(..)))
{
printLogMessage("[Before Runnable.run() / Callable.call()]",
runnableCallable);
Object result = proceed(runnableCallable);
printLogMessage("[After Runnable.run() / Callable.call()]",
runnableCallable);
return result;
}
private void printLogMessage(String prefix,
InstrumentedRunnableCallable runnableCallable) {
System.out.printf("%s TID=%d, %s%n", prefix,
Thread.currentThread().getId(), runnableCallable.toStringIRC());
}
public String InstrumentedRunnableCallable.toStringIRC() {
return getClass().getName() + "(instanceID=" + _id + ",
creatorTID=" + _creator_tid + ")";
}
}
My aspect could be over-engineered for usual use cases.
Added extra needed synchronization in your aspect
package de.scrum_master.aspect;
import static java.lang.Thread.currentThread;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
public privileged aspect RunnablesCallablesAspect {
private static final Map<Class<?>, Long> instanceCounters = new
ConcurrentHashMap<>();
public static synchronized long getInstanceCounter(Class<?> clazz) {
Long counter = instanceCounters.get(clazz);
return counter == null ? 0 : counter;
}
private static synchronized void incrementInstanceCounter(Class<?> clazz) {
instanceCounters.put(clazz, getInstanceCounter(clazz) + 1);
}
// Only for demo purposes, can be deleted
private static final java.util.Random RANDOM = new java.util.Random();
private static void incrementInstanceCounterThreadUnsafe(Class<?> clazz) {
long counter = getInstanceCounter(clazz);
try {
Thread.sleep(RANDOM.nextInt(10));
} catch (InterruptedException e) {
throw new org.aspectj.lang.SoftException(e);
}
instanceCounters.put(clazz, counter + 1);
}
after() returning(InstrumentedRunnableCallable runnableCallable) :
call(InstrumentedRunnableCallable+.new(..))
{
runnableCallable.setCreatorTID(currentThread().getId());
synchronize(instanceCounters){
runnableCallable.setId(getInstanceCounter(runnableCallable.getClass()));
incrementInstanceCounter(runnableCallable.getClass());
}
// Use this instead in order to mess up instance counters
//incrementInstanceCounterThreadUnsafe(runnableCallable.getClass());
printLogMessage("[Create Runnable/Callable]", runnableCallable);
}
Object around(InstrumentedRunnableCallable runnableCallable):
this(runnableCallable) &&
(execution(void Runnable+.run(..)) || execution(* Callable+.call(..)))
{
printLogMessage("[Before Runnable.run() / Callable.call()]",
runnableCallable);
Object result = proceed(runnableCallable);
printLogMessage("[After Runnable.run() / Callable.call()]",
runnableCallable);
return result;
}
private void printLogMessage(String prefix,
InstrumentedRunnableCallable runnableCallable) {
System.out.printf("%s TID=%d, %s%n", prefix,
currentThread().getId(), runnableCallable.toStringIRC());
}
public interface InstrumentedRunnableCallable {}
private long InstrumentedRunnableCallable.id = -1;
private long InstrumentedRunnableCallable.creatorTID = -1;
public long InstrumentedRunnableCallable.getId() { return id; }
public void InstrumentedRunnableCallable.setId(long id) { this.id = id; }
public long InstrumentedRunnableCallable.getCreatorTID() { return
creatorTID; }
public void InstrumentedRunnableCallable.setCreatorTID(long
creatorTID) { this.creatorTID = creatorTID; }
public String InstrumentedRunnableCallable.toStringIRC() {
return getClass().getName() + "(instanceID=" + id + ",
creatorTID=" + creatorTID + ")";
}
declare parents: Runnable+ implements InstrumentedRunnableCallable;
declare parents: Callable+ implements InstrumentedRunnableCallable;
}
Thank you again for your responsiveness. Please feel free to give any more
advice.
regards,
Yongle
On May 22, 2018 at 7:45:10 AM, Alexander Kriegisch ([email protected])
wrote:
Hi Yongle!
ThreadLocal (TL) is not helping you here, as I said. Either you
misunderstand what TL does or it was just a simple error in your analysis
or maybe a refactoring artifact. Maybe in an older implementation of your
code it was somehow helpful, but certainly not here. Here is a refactored
aspect. I changed several things, among them the following:
- As I said, no more ThreadLocal, i.e. also no more null checks.
- Got rid of unnecessary boolean flag in the interface implementation.
If you wanted to, you could just check if the ID or creator thread ID are
!= -1 in order to find out if the members have been initialised or not. But
actually that is not necessary because the "after returning" advice for
constructor calls will not trigger for super class constructors or calls
like this(11) in constructors.
- Made the accessor methods for the counters in the map synchronized.
Synchronizing on whole classes like you did is a bit too much. I also got
rid of the set* method, the increment* one is enough. I also made
everything but getInstanceCounter(Class<?> clazz) private, and the
latter is only public because the driver application uses it for checking
if the counters are as expected.
- Changed the static map into a ConcurrentHashMap. Actually this is not
strictly necessary for this implementation because the accessor methods are
already synchronised, but it does not hurt either.
- Added a non-threadsafe method
incrementInstanceCounterThreadUnsafe(Class<?>
clazz) which you can use to demonstrate how *not* to do it. This
demonstrates that ConcurrentHashMap does not help at all if you just do
synchronisation wrong.
- Compounded your before/after advices into one around advice.
- Factored out some redundant logging code into a helper method.
- Renamed your members to use the Java standardNamingStyle instead of
Non_standardScheme. I also got rid of the irritating "My_" prefix.
- Also renamed members and accessor methods in the interface
implementation.
- Renamed the whole aspect.
- Added some more complexity to the driver application with the sample
classes in order to more properly test for concurrency.
So here is the revised code:
------------------------------
package de.scrum_master.app;
class RunnableBase implements Runnable {
@Override
public void run() {
// System.out.println("Running runnable base");
}
}
------------------------------
package de.scrum_master.app;
class SomeRunnable extends RunnableBase {
public SomeRunnable() {
this(11);
// System.out.println("SomeRunnable default constructor");
}
public SomeRunnable(int dummyParameter) {
super();
// System.out.println("SomeRunnable parametrised constructor");
}
@Override
public void run() {
// System.out.println("Running some runnable");
}
}
------------------------------
package de.scrum_master.app;
import static
de.scrum_master.aspect.RunnablesCallablesAspect.getInstanceCounter;
import static java.lang.System.currentTimeMillis;
public class Application {
private static class InnerStaticRunnable implements Runnable {
@Override
public void run() {
// System.out.println("Running inner static runnable");
}
}
private class InnerRunnable implements Runnable {
@Override
public void run() {
// System.out.println("Running inner runnable");
new Thread(new SomeRunnable()).start();
}
}
public void doSomething() {
new Thread(new InnerRunnable()).start();
new Thread(new SomeRunnable()).start();
}
private static void checkCounter(Class<?> clazz, long expectedCount)
throws RuntimeException {
long instanceCounter = getInstanceCounter(clazz);
if (instanceCounter != expectedCount)
throw new RuntimeException(
"Unexpected counter value for class " + clazz.getName() +
": expected="+ expectedCount +
", actual=" + instanceCounter
);
}
public static void main(String[] args) throws InterruptedException {
final int MAX_COUNT = 100;
long startTime = currentTimeMillis();
for (int i = 0; i < MAX_COUNT; i++) {
new Thread(new SomeRunnable()).start();
new Thread(new Application.InnerStaticRunnable()).start();
new Application().doSomething();
new Thread(new RunnableBase()).start();
}
Thread.sleep(250); // Unelegant way to wait for threads to finish
System.out.printf("Duration (minus sleeping time) = %d ms%n",
currentTimeMillis() - startTime - 250);
checkCounter(Application.InnerStaticRunnable.class, MAX_COUNT);
checkCounter(Application.InnerRunnable.class, MAX_COUNT);
checkCounter(SomeRunnable.class, MAX_COUNT * 3);
checkCounter(RunnableBase.class, MAX_COUNT);
}
}
------------------------------
package de.scrum_master.aspect;
import static java.lang.Thread.currentThread;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
public privileged aspect RunnablesCallablesAspect {
private static final Map<Class<?>, Long> instanceCounters = new
ConcurrentHashMap<>();
public static synchronized long getInstanceCounter(Class<?> clazz) {
Long counter = instanceCounters.get(clazz);
return counter == null ? 0 : counter;
}
private static synchronized void incrementInstanceCounter(Class<?> clazz) {
instanceCounters.put(clazz, getInstanceCounter(clazz) + 1);
}
// Only for demo purposes, can be deleted
private static final java.util.Random RANDOM = new java.util.Random();
private static void incrementInstanceCounterThreadUnsafe(Class<?> clazz) {
long counter = getInstanceCounter(clazz);
try {
Thread.sleep(RANDOM.nextInt(10));
} catch (InterruptedException e) {
throw new org.aspectj.lang.SoftException(e);
}
instanceCounters.put(clazz, counter + 1);
}
after() returning(InstrumentedRunnableCallable runnableCallable) :
call(InstrumentedRunnableCallable+.new(..))
{
runnableCallable.setCreatorTID(currentThread().getId());
runnableCallable.setId(getInstanceCounter(runnableCallable.getClass()));
incrementInstanceCounter(runnableCallable.getClass());
// Use this instead in order to mess up instance counters
//incrementInstanceCounterThreadUnsafe(runnableCallable.getClass());
printLogMessage("[Create Runnable/Callable]", runnableCallable);
}
Object around(InstrumentedRunnableCallable runnableCallable):
this(runnableCallable) &&
(execution(void Runnable+.run(..)) || execution(* Callable+.call(..)))
{
printLogMessage("[Before Runnable.run() / Callable.call()]",
runnableCallable);
Object result = proceed(runnableCallable);
printLogMessage("[After Runnable.run() / Callable.call()]",
runnableCallable);
return result;
}
private void printLogMessage(String prefix,
InstrumentedRunnableCallable runnableCallable) {
System.out.printf("%s TID=%d, %s%n", prefix,
currentThread().getId(), runnableCallable.toStringIRC());
}
public interface InstrumentedRunnableCallable {}
private long InstrumentedRunnableCallable.id = -1;
private long InstrumentedRunnableCallable.creatorTID = -1;
public long InstrumentedRunnableCallable.getId() { return id; }
public void InstrumentedRunnableCallable.setId(long id) { this.id = id; }
public long InstrumentedRunnableCallable.getCreatorTID() { return
creatorTID; }
public void InstrumentedRunnableCallable.setCreatorTID(long
creatorTID) { this.creatorTID = creatorTID; }
public String InstrumentedRunnableCallable.toStringIRC() {
return getClass().getName() + "(instanceID=" + id + ",
creatorTID=" + creatorTID + ")";
}
declare parents: Runnable+ implements InstrumentedRunnableCallable;
declare parents: Callable+ implements InstrumentedRunnableCallable;
}
------------------------------
Enjoy!
--
Alexander Kriegisch
https://scrum-master.de
Yongle Zhang schrieb am 21.05.2018 21:29:
ThreadLocal is used to avoid multiple threads creating objects of the same
class and need to increment the counter at the same time.
Thanks for your time reviewing it! I’d really appreciate it if you want to
help to refactor it.
On May 21, 2018 at 9:58:16 AM, Alexander Kriegisch ([email protected])
wrote:
I am happy you found a workaround for your problem, although it seems a bit
over-engineered. There are several parts which could use refactoring, but
most of all I am irritated by the ThreadLocal. Why would you need that? You
are keeping only one ID (truly just a simple counter) per class. What are
you gaining by using the ThreadLocal there?
Yongle Zhang schrieb am 21.05.2018 02:17:
Thank you for your quick reply! Really appreciate your effort!
In terms of my original goal, I had to come up with some workaround.
The general idea is to just maintain a Map<java.lang.class, counter> by
myself. There’s some synchronization and optimization to do.
I’ll post here in case it’s helpful for others.
To make it clear, this method works for “inserting an ID for objects of
classes in any jar” except for rt.jar.
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.lang.Runnable;
privileged aspect MyRunnablesCallables {
public static Map<java.lang.Class, ThreadLocal<Long>> My_counters = new
HashMap<java.lang.Class, ThreadLocal<Long>>();
public static long getMyCounter(java.lang.Class clazz) {
ThreadLocal<Long> local = My_counters.get(clazz);
if (local == null) {
// need to initialize the ThreadLocal
// This is the only place that needs synchronization.
synchronized (clazz) { // synchronize on the given clazz is enough
// Double check to avoid multi threads entered the previous if statement
if (local == null) {
local = new ThreadLocal<Long>() {
@Override
protected Long initialValue() {
return (long) 0;
}
};
My_counters.put(clazz, local);
}
}
}
return (long) local.get();
}
private static void setMyCounter(java.lang.Class clazz, long counter) {
ThreadLocal<Long> local = My_counters.get(clazz);
// This function is only called in incrementMyCounter() so it's not null.
assert local != null;
local.remove();
local.set(counter);
}
public static void incrementMyCounter(java.lang.Class clazz) {
setMyCounter(clazz, getMyCounter(clazz)+1);
}
public interface InstrumentedRunnableCallable {}
private boolean InstrumentedRunnableCallable.My_id_assigned = false;
// here we use (thread id + a thread local id) as this object's ID.
// For now we don't consider the case when Thread ID could be reused.
private long InstrumentedRunnableCallable.My_id = -1;
private long InstrumentedRunnableCallable.My_creator_tid = -1;
public long InstrumentedRunnableCallable.getMyId() {
return My_id;
}
public void InstrumentedRunnableCallable.setMyId(long id) {
My_id = id;
}
public long InstrumentedRunnableCallable.getCreatorTid() {
return My_creator_tid;
}
public void InstrumentedRunnableCallable.setCreatorTid(long id) {
My_creator_tid = id;
}
public boolean InstrumentedRunnableCallable.getMyIdAssigned() {
return My_id_assigned;
}
public void InstrumentedRunnableCallable.setMyIdAssigned(boolean assigned) {
My_id_assigned = assigned;
}
declare parents: (Runnable)+ implements InstrumentedRunnableCallable;
declare parents: (Callable)+ implements InstrumentedRunnableCallable;
after() returning(InstrumentedRunnableCallable r):
(call(InstrumentedRunnableCallable+.new(..))) {
if (r.getMyIdAssigned() == false) { // in case there're nested constructors
r.setMyIdAssigned(true);
r.setCreatorTid(Thread.currentThread().getId());
r.setMyId(MyRunnablesCallables.getMyCounter(r.getClass()));
MyRunnablesCallables.incrementMyCounter(r.getClass());
}
System.out.println( "[Create Runnable/Callable] " +
"TID: " + Thread.currentThread().getId()
+ " creator tid " + r.getCreatorTid()
+ " id " + r.getMyId()
+ " class " + r.getClass().getName()
);
}
before(InstrumentedRunnableCallable r):
this(r) &&
(execution(void Runnable+.run(..)) || execution(* Callable+.call(..))) {
System.out.println( "[Before Runnable run() / Callable call() ] " +
"TID: " + Thread.currentThread().getId()
+ " creator tid " + r.getCreatorTid()
+ " id " + r.getMyId()
+ " class " + r.getClass().getName()
);
}
after(InstrumentedRunnableCallable r):
this(r) &&
(execution(void Runnable+.run(..)) || execution(* Callable+.call(..))) {
System.out.println( "[After Runnable run() / Callable call() ] " +
"TID: " + Thread.currentThread().getId()
+ " creator tid " + r.getCreatorTid()
+ " id " + r.getMyId()
+ " class " + r.getClass().getName()
);
}
}
On May 19, 2018 at 7:01:56 AM, Alexander Kriegisch ([email protected])
wrote:
Okay, I think I figured it out. It is not per se a problem with the 3rd
party code, I can reproduce it with or without Thrift. The core problem is
that the inner class you want to instrument in the library is non-public.
To be exact, it is a private, non-static inner class. But what really
matters is that it is anything but public/protected, static or not is not
so important.
To Andy Clement: Maybe this is a shortcoming in AspectJ and we need a
Bugzilla ticket for it, but first I am going to post some sample code here:
------------------------------
package de.scrum_master.app;
public class Application {
private static class InnerStaticRunnable implements Runnable {
@Override
public void run() {
System.out.println("Running inner static runnable");
}
}
private class InnerRunnable implements Runnable {
@Override
public void run() {
System.out.println("Running inner runnable");
}
}
public void doSomething() {
new InnerRunnable().run();
}
public static void main(String[] args) {
new SomeRunnable().run();
new Application.InnerStaticRunnable().run();
new Application().doSomething();
}
}
------------------------------
package de.scrum_master.aspect;
privileged aspect MyRunnables {
public interface InstrumentedRunnable {}
private long InstrumentedRunnable.myid = -1;
public long InstrumentedRunnable.getMyid() { return myid; }
public void InstrumentedRunnable.setMyid(long id) { myid = id; }
declare parents : Runnable+ implements InstrumentedRunnable;
after() returning(InstrumentedRunnable r) :
call(java.lang.Runnable+.new(..)) {
System.out.println(thisJoinPoint);
System.out.println(" Runnable: " + r);
System.out.println(" Has aspect: " + PerRunnable.hasAspect(r.getClass()));
long id = PerRunnable.aspectOf(r.getClass()).getCounter();
r.setMyid(id);
PerRunnable.aspectOf(r.getClass()).incrementCounter();
}
}
------------------------------
package de.scrum_master.aspect;
privileged aspect PerRunnable pertypewithin(java.lang.Runnable+) {
public long counter = 0;
public long getCounter() { return counter; }
public void incrementCounter() { counter++; }
after() : staticinitialization(*) {
System.out.println("getWithinTypeName() = " + getWithinTypeName());
}
}
------------------------------
Now let's run the code after Ajc compilation and check the console log:
getWithinTypeName() = de.scrum_master.app.SomeRunnable
call(de.scrum_master.app.SomeRunnable())
Runnable: de.scrum_master.app.SomeRunnable@5674cd4d
Has aspect: true
Running some runnable
getWithinTypeName() = de.scrum_master.app.Application$InnerStaticRunnable
call(de.scrum_master.app.Application.InnerStaticRunnable(Application.InnerStaticRunnable))
Runnable: de.scrum_master.app.Application$InnerStaticRunnable@65b54208
Has aspect: false
Exception in thread "main" org.aspectj.lang.NoAspectBoundException
at de.scrum_master.aspect.PerRunnable.aspectOf(PerRunnable.aj:1)
at
de.scrum_master.aspect.MyRunnables.ajc$afterReturning$de_scrum_master_aspect_MyRunnables$1$8a935d86(MyRunnables.aj:15)
at de.scrum_master.app.Application.main(Application.java:24)
------------------------------
Please note "Has aspect: false" right before the exception. Now change the
inner classes to public or protected and the code works:
getWithinTypeName() = de.scrum_master.app.SomeRunnable
call(de.scrum_master.app.SomeRunnable())
Runnable: de.scrum_master.app.SomeRunnable@5674cd4d
Has aspect: true
Running some runnable
getWithinTypeName() = de.scrum_master.app.Application$InnerStaticRunnable
call(de.scrum_master.app.Application.InnerStaticRunnable())
Runnable: de.scrum_master.app.Application$InnerStaticRunnable@65b54208
Has aspect: true
Running inner static runnable
getWithinTypeName() = de.scrum_master.app.Application$InnerRunnable
call(de.scrum_master.app.Application.InnerRunnable(Application))
Runnable: de.scrum_master.app.Application$InnerRunnable@6b884d57
Has aspect: true
Running inner runnable
------------------------------
Any comments, Andy?
--
Alexander Kriegisch
https://scrum-master.de
Yongle Zhang schrieb am 18.05.2018 04:03:
More information
- The part of the code that’s causing the exception - this is decompiled
from the woven .class file:
public class TThreadPoolServer {
public void serve() {
. . .
TThreadPoolServer.WorkerProcess var13;
TThreadPoolServer.WorkerProcess var10000 = var13 = new
TThreadPoolServer.WorkerProcess(client, (<undefinedtype>)var10);
// The exception says here afterReturning throws the exception
EpredRunnablesCallables.aspectOf().ajc$afterReturning$EpredRunnablesCallables$1$8a935d86(var13);
. . .
}
// inner class
private class WorkerProcess implements Runnable,
InstrumentedRunnableCallable {
public long myid; // inserted by aspectj
. . .
}
}
- Question: how does pertypewithin() work? what’s its scope?
For example, pertypewithin(Runnable+) - does it work every class in the
classpath, even including those in rt.jar? When does it create instance for
every class that implements Runnable (after class loading, on demand, …)?
Thank you!
On May 17, 2018 at 4:36:23 PM, Yongle Zhang ([email protected]) wrote:
Hi,
Problem
I have some aspects trying to insert an ID for every class that implements
Runnable.
My aspects (provided below) works fine for a simple test in which 1) I
wrote my own MyRunnable class implementing Runnable, 2) I have a simple
main function that creates and runs a thread using MyRunnable.
However, when I use it to instrument apache thrift library, it gives me
org.aspectj.lang.NoAspectBoundException exception.
I use compile-time weaving. The compile-time weaving finishes successfully,
and the instrumented .class code shows the aspects was woven. However,
running the instrumented apache thrift lib gives this excetpion:
(MyServer is my simple server implementation using thrift.
TThreadPoolServer is the server class in apache thrift lib.)
org.aspectj.lang.NoAspectBoundException
at EpredPerRunnable.aspectOf(EpredPerRunnable.aj:1)
at
EpredRunnablesCallables.ajc$afterReturning$EpredRunnablesCallables$1$8a935d86(EpredRunnablesCallables.aj:55)
at
org.apache.thrift.server.TThreadPoolServer.serve(TThreadPoolServer.java:168)
at MyServer.StartsimpleServer(MyServer.java:21)
at MyServer.main(MyServer.java:28)
My Aspects
Here are the aspects I wrote:
1) I have a counter for each class implements Runnable using pertypewithin.
privileged aspect PerRunnable
pertypewithin(java.lang.Runnable+)
{
public long counter = 0;
public long getCounter() {
return counter;
}
public void incrementCounter() {
counter++;
}
}
2) I insert an id into each class that implements Runnable using interface.
privileged aspect MyRunnables {
public interface InstrumentedRunnable {}
private long InstrumentedRunnable.myid = -1;
public long InstrumentedRunnable.getMyid() {
return myid;
}
public void InstrumentedRunnable.setMyid(long id) {
myid = id;
}
declare parents: (Runnable)+ implements InstrumentedRunnable;
after() returning(InstrumentedRunnable r):
call(java.lang.Runnable+.new(..)) {
long id = PerRunnable.aspectOf(r.getClass()).getCounter();
r.setMyid(id);
PerRunnable.aspectOf(r.getClass()).incrementCounter();
}
}
3) Part of my scripts that only instruments thrift:
CLASSPATH=$CLASSPATH:~/aspectj1.9/lib/aspectjtools.jar
CLASSPATH=$CLASSPATH:~/aspectj1.9/lib/aspectjrt.jar
AJC=~/aspectj1.9/bin/ajc
echo "Compiling Aspects ..."
$AJC -classpath $CLASSPATH:./lib/libthrift-0.11.0.jar -source 1.8 asp/*.aj
echo "Weaving aspect into thrift lib..."
$AJC -classpath
$CLASSPATH:./lib/servlet-api-2.5.jar:./lib/httpcore-4.4.1.jar:./lib/slf4j-api-1.7.12.jar:./lib/httpclient-4.4.1.jar
-source 1.8 -inpath ./lib/libthrift-0.11.0.jar -aspectpath ./asp/
-outjar ./my-libthrift-0.11.0.jar
4) Part of my scripts that starts the thrift server:
CLASSPATH=$CLASSPATH:~/aspectj1.9/lib/aspectjtools.jar
CLASSPATH=$CLASSPATH:~/aspectj1.9/lib/aspectjrt.jar
java -cp
$CLASSPATH:./asp:./my-add-server.jar:./my-libthrift-0.11.0.jar:./lib/slf4j-api-1.7.12.jar
MyServer
Need Help
1. Has anyone met such problem before? Any guess? Note that these
aspects works for my own Runnable but not for thrift lib. (I can send more
code needed including my test classes and my scripts, but they don’t fit
within an email…)
2. Is there a way to get all aspect instances and what they are matched
to at runtime?
3. Does aspectj has this feature: given 1) a pointcut, 2) the signature
of a target (class/method) I want the pointcut to match, tell me whether
they matched, and if not why.
Thank you for your time and help!
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