Re: [aspectj-users] Plans for the next release of AspectJ...

[Adrian Colyer <adrian_colyer@xxxxxxxxxx>]

> aload_0
> getfield <Field java.lang.Object lock>
> dup
> astore_2
> monitorenter 
> ....         -> here matches monitor(Object
Test.test), This is FIELD_PAT
>                 also this
matches monitor(Object) this is TYPE_PAT
> monitorexit

you mean 'matches monitor(Object Test.lock)'
for the FIELD_PAT, right?

For the contrived example

void foo() {

  Object lock = new Object();
  someoneElse.passLockReference(lock);
  synchronized(lock) {
      // ...
  }
}

you could only ever match on TYPE_PAT,
and not FIELD_PAT?


I fully understand the value of this
for tracing / debugging / instrumenting multi-threaded applications. I'd
be very interested to hear use cases anyone has for this proposed extension
that go beyond such examples.

-- Adrian
Adrian_Colyer@xxxxxxxxxx

Toru Watanabe <t-watanabe@xxxxxxxxxxxxx> Sent by: aspectj-users-admin@xxxxxxxxxxx 17/12/2003 10:11 Please respond to aspectj-users

To:        aspectj-users@xxxxxxxxxxx         cc:                 Subject:        Re: [aspectj-users] Plans for the next release of AspectJ...

Hi Gregor,

Gregor> Can you give a couple of small example programs showing how
Gregor> you'd use this? At least one with TYPE_PAT and one with
Gregor> FIELD_PAT?  One issue is that I'm not sure I can see how
Gregor> field_pat would work stably.

TYPE_PAT and FIELD_PAT are same as TypePat and FieldPat described in
aspectj quick reference (ASPECTJ_HOME/doc/quick.pdf).

Now, I show my image of monitor pointcut.
Supporse there is a class which name is Test, and method test has
synchronized blocks like following.
public class Test {
 Object lock = new Object();
 public void test(){
  syncronized(this){
   //do something
  }
  synchronized(lock){
   //do something
  }
 }
}

then, this class will be and mapped like following instructions.

aload_0
dup
astore_1
monitorenter
....         -> here matches monitor(Test), monitor(Object+)
these are TYPE_PAT
monitorexit

aload_0
getfield <Field java.lang.Object lock>
dup
astore_2
monitorenter 
....         -> here matches monitor(Object Test.test),
This is FIELD_PAT
                also this matches
monitor(Object) this is TYPE_PAT
monitorexit

For synchronized method, like
 public syncronized void test2(){
   //do something
 }
 public static syncronized void test3(){
   //do something
 }

you can assume above codes like followings (note binary codes are different)

  public void test2(){
   synchronized(this){
    //do something
   }
  }
  public static void test3(){
   synchronized(Test.class){
    //do something
   }
  }
 
So it is good if synchronized methods also matche monitor pointcut.

Best regards,
Watanabe
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