A transaction question

[neo anderson]

I am learning how to modulize transaction using aspectj, but encounter a problem that EntityManager I try to capture is always null. The compiler issues message saying that the advice can not be applied. as below:

... advice defined in example.AbstractTransaction has not been applied [Xlint:adviceDidNotMatch]

What should I change so that I can capture the EntityManager while it is created (whilst calling to AccountDao.setEntityManager(..))?

Thanks for help.

Main.java

package example;

public class Main{
        public static void main(String args[]){
                Main m = new Main();
                m.process();
        }
        void process(){
                AccountDao dao = new AccountDao();
                dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
                User u = new User("1", "Smith");
                u.setAddress("123 Test Road, London.");
                dao.save(u);

                dao.list();
        }
}

AccountDao.java

package example;

import java.util.List;
import java.util.ArrayList;


public class AccountDao{

        private EntityManager manager;

        private static List<User> database = new ArrayList<User>();

        public void setEntityManager(EntityManager manager){
                this.manager = manager;
        }

        public void save(User user){
                database.add(user);
        }

        public void list(){
                for(User u : database){
                        System.out.println(">>>[AccountDao.java]"+u);
                }
        }
}

User.java

package example;

public class User{
        private String id;
        private String name;
        private String address;
        public User(String id, String name){
                this.id = id;
                this.name = name;
        }

        public String getId(){
                return this.id;
        }

        public String getName(){
                return this.name;
        }

        public String getAddress(){
                return this.address;
        }

        public void setAddress(String address){
                this.address = address;
        }

        public String toString(){
                return "<User [id:"+id+"][name:"+name+"][address:"+address+"]>";
        }
}


PersistenceCreator.java

package example;

public class PersistenceCreator{
        private static EntityManagerFactory factory;

        public static EntityManagerFactory createEntityManagerFactory(){
                if(null == factory)
                        factory = new EntityManagerFactory();
                return factory;
        }
}

EntityManagerFactory.java

package example;

public class EntityManagerFactory{

        private static EntityManager manager;

        public static EntityManager createEntityManager(){
                if(null == manager){
                        manager = new EntityManager();
                }
                return manager;
        }
}

EntityManager.java

package example;

public class EntityManager{
}

AbstractTransaction.aj

package example;

public abstract aspect AbstractTransaction percflow(scope()){

        private EntityManager manager;
       
        protected abstract pointcut tx();

        protected pointcut obtainEntityManager(EntityManager manager): call(* example.AccountDao.setEntityManager(EntityManager)) && target(manager);

        protected pointcut scope(): tx() && !cflowbelow(tx());

        Object around(): scope(){
                System.out.println("EntityManager:"+manager);// always null
                Object result = proceed();
                return result;
        }

        EntityManager around(EntityManager manager): obtainEntityManager(manager) && cflow(tx()){
                if(null == manager){
                        manager = proceed(manager);
               
                }
                return manager;
        }
}

AccountTransaction.aj

package example;

public aspect AccountTransaction extends AbstractTransaction{

        protected pointcut tx(): execution(* example.Main.process());
}

[Andy Clement]

Just a quick observation:

 protected pointcut obtainEntityManager(EntityManager manager): call(*
example.AccountDao.setEntityManager(EntityManager)) && target(manager);

shouldn't that be:

 protected pointcut obtainEntityManager(EntityManager manager): call(*
example.AccountDao.setEntityManager(EntityManager)) && args(manager);

As the EntityManager is the argument to the method call and not the
target of the call (the target of the call being AccountDao)?

Andy

2009/11/4 neo anderson <javadeveloper999@...>:

>
> I am learning how to modulize transaction using aspectj, but encounter a
> problem that EntityManager I try to capture is always null. The compiler
> issues message saying that the advice can not be applied. as below:
>
> ... advice defined in example.AbstractTransaction has not been applied
> [Xlint:adviceDidNotMatch]
>
> What should I change so that I can capture the EntityManager while it is
> created (whilst calling to AccountDao.setEntityManager(..))?
>
> Thanks for help.
>
> Main.java
>
> package example;
>
> public class Main{
>        public static void main(String args[]){
>                Main m = new Main();
>                m.process();
>        }
>        void process(){
>                AccountDao dao = new AccountDao();
>
> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>                User u = new User("1", "Smith");
>                u.setAddress("123 Test Road, London.");
>                dao.save(u);
>
>                dao.list();
>        }
> }
>
> AccountDao.java
>
> package example;
>
> import java.util.List;
> import java.util.ArrayList;
>
>
> public class AccountDao{
>
>        private EntityManager manager;
>
>        private static List<User> database = new ArrayList<User>();
>
>        public void setEntityManager(EntityManager manager){
>                this.manager = manager;
>        }
>
>        public void save(User user){
>                database.add(user);
>        }
>
>        public void list(){
>                for(User u : database){
>                        System.out.println(">>>[AccountDao.java]"+u);
>                }
>        }
> }
>
> User.java
>
> package example;
>
> public class User{
>        private String id;
>        private String name;
>        private String address;
>        public User(String id, String name){
>                this.id = id;
>                this.name = name;
>        }
>
>        public String getId(){
>                return this.id;
>        }
>
>        public String getName(){
>                return this.name;
>        }
>
>        public String getAddress(){
>                return this.address;
>        }
>
>        public void setAddress(String address){
>                this.address = address;
>        }
>
>        public String toString(){
>                return "<User [id:"+id+"][name:"+name+"][address:"+address+"]>";
>        }
> }
>
>
> PersistenceCreator.java
>
> package example;
>
> public class PersistenceCreator{
>        private static EntityManagerFactory factory;
>
>        public static EntityManagerFactory createEntityManagerFactory(){
>                if(null == factory)
>                        factory = new EntityManagerFactory();
>                return factory;
>        }
> }
>
> EntityManagerFactory.java
>
> package example;
>
> public class EntityManagerFactory{
>
>        private static EntityManager manager;
>
>        public static EntityManager createEntityManager(){
>                if(null == manager){
>                        manager = new EntityManager();
>                }
>                return manager;
>        }
> }
>
> EntityManager.java
>
> package example;
>
> public class EntityManager{
> }
>
> AbstractTransaction.aj
>
> package example;
>
> public abstract aspect AbstractTransaction percflow(scope()){
>
>        private EntityManager manager;
>
>        protected abstract pointcut tx();
>
>        protected pointcut obtainEntityManager(EntityManager manager): call(*
> example.AccountDao.setEntityManager(EntityManager)) && target(manager);
>
>        protected pointcut scope(): tx() && !cflowbelow(tx());
>
>        Object around(): scope(){
>                System.out.println("EntityManager:"+manager);// always null
>                Object result = proceed();
>                return result;
>        }
>
>        EntityManager around(EntityManager manager): obtainEntityManager(manager)
> && cflow(tx()){
>                if(null == manager){
>                        manager = proceed(manager);
>
>                }
>                return manager;
>        }
> }
>
> AccountTransaction.aj
>
> package example;
>
> public aspect AccountTransaction extends AbstractTransaction{
>
>        protected pointcut tx(): execution(* example.Main.process());
> }
> --
> View this message in context: http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
> Sent from the AspectJ - users mailing list archive at Nabble.com.
>
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@...
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>

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[Mark Cooke-6]

Hi,
It's been a while since I've used AspectJ in anger but as no-one else has replied yet...

I'd say you probably want "args(manager)" instead of "target(manager)" in the obtainEntityManager pointcut.
The target of the call will be an AccountDAO, not an EntityManager.

See http://www.eclipse.org/aspectj/doc/released/progguide/semantics-joinPoints.html

HTH!
Mark.

--- On Wed, 4/11/09, neo anderson <javadeveloper999@...> wrote:

> From: neo anderson <javadeveloper999@...>
> Subject: [aspectj-users] A transaction question
> To: aspectj-users@...
> Date: Wednesday, 4 November, 2009, 12:09
>
> I am learning how to modulize transaction using aspectj,
> but encounter a
> problem that EntityManager I try to capture is always null.
> The compiler
> issues message saying that the advice can not be applied.
> as below:
>
> ... advice defined in example.AbstractTransaction has not
> been applied
> [Xlint:adviceDidNotMatch]
>
> What should I change so that I can capture the
> EntityManager while it is
> created (whilst calling to
> AccountDao.setEntityManager(..))?
>
> Thanks for help.
>
> Main.java
>
> package example;
>
> public class Main{
>     public static void main(String args[]){
>         Main m = new Main();
>         m.process();
>     }
>     void process(){
>         AccountDao dao = new
> AccountDao();
>    
> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>         User u = new
> User("1", "Smith");
>         u.setAddress("123
> Test Road, London.");
>         dao.save(u);
>
>        
> dao.list();   
>     }
> }
>
> AccountDao.java
>
> package example;
>
> import java.util.List;
> import java.util.ArrayList;
>
>
> public class AccountDao{
>
>     private EntityManager manager;
>
>     private static List<User> database
> = new ArrayList<User>();
>
>     public void
> setEntityManager(EntityManager manager){
>         this.manager =
> manager;
>     }   
>
>     public void save(User user){
>        
> database.add(user);   
>     }
>
>     public void list(){
>         for(User u :
> database){
>            
> System.out.println(">>>[AccountDao.java]"+u);   
>
>         }
>     }
> }
>
> User.java
>
> package example;
>
> public class User{
>     private String id;
>     private String name;
>     private String address;
>     public User(String id, String name){
>         this.id = id;
>         this.name = name;
>     }
>
>     public String getId(){
>         return this.id;
>     }
>
>     public String getName(){
>         return this.name;
>     }
>
>     public String getAddress(){
>         return this.address;
>     }
>
>     public void setAddress(String address){
>         this.address =
> address;
>     }
>
>     public String toString(){
>         return "<User
> [id:"+id+"][name:"+name+"][address:"+address+"]>";
>     }
> }
>
>
> PersistenceCreator.java
>
> package example;
>
> public class PersistenceCreator{
>     private static EntityManagerFactory
> factory;
>
>     public static EntityManagerFactory
> createEntityManagerFactory(){
>         if(null == factory)
>            
> factory = new EntityManagerFactory();
>         return factory;
>     }
> }
>
> EntityManagerFactory.java
>
> package example;
>
> public class EntityManagerFactory{
>
>     private static EntityManager manager;
>
>     public static EntityManager
> createEntityManager(){
>         if(null == manager){
>            
> manager = new EntityManager();
>         }
>         return manager;
>     }
> }
>
> EntityManager.java
>
> package example;
>
> public class EntityManager{
> }
>
> AbstractTransaction.aj
>
> package example;
>
> public abstract aspect AbstractTransaction
> percflow(scope()){
>
>     private EntityManager manager;
>    
>     protected abstract pointcut tx();
>
>     protected pointcut
> obtainEntityManager(EntityManager manager): call(*
> example.AccountDao.setEntityManager(EntityManager))
> && target(manager);
>
>     protected pointcut scope(): tx()
> && !cflowbelow(tx());
>
>     Object around(): scope(){
>        
> System.out.println("EntityManager:"+manager);// always null
>
>         Object result =
> proceed();
>         return result;
>     }
>
>     EntityManager around(EntityManager
> manager): obtainEntityManager(manager)
> && cflow(tx()){
>         if(null == manager){
>            
> manager = proceed(manager);
>        
>         }

>         return manager;
>     }
> }
>
> AccountTransaction.aj
>
> package example;
>
> public aspect AccountTransaction extends
> AbstractTransaction{
>
>     protected pointcut tx(): execution(*
> example.Main.process());
> }
> --
> View this message in context: http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
> Sent from the AspectJ - users mailing list archive at
> Nabble.com.
>
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@...
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>

_______________________________________________
aspectj-users mailing list
aspectj-users@...
https://dev.eclipse.org/mailman/listinfo/aspectj-users

[neo anderson]

Hi Mark & Andy. Thanks for your reply. I really appreciate your help.

I change to use args, but now it thorws message:

[error] incompatible return type applying to method-call(void example.AccountDao.setEntityManager(example.EntityManager))

[error] incompatible return type applying to method-call(void example.AccountDao.setEntityManager(example.EntityManager))
dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());

[warning] advice defined in example.AbstractTransaction has not been applied [Xlint:adviceDidNotMatch]

I check the syntax and read the example in e.g. http://books.google.com.tw/books?id=AKuBlJGl7iUC&pg=PA54&lpg=PA54&dq=aspectj+call+args&source=bl&ots=58KGnyCZiN&sig=5gNdHoekFrDXJne3pVe6UO5tiYQ&hl=zh-TW&ei=kNbxSqTEBumgjAfdnp2WAQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CB0Q6AEwBQ#v=onepage&q=4-2%20capturing%20the%20parameter%20values%20passed%20on%20a%20method%20call&f=false

The way to capture the EntityManager looks correct.

public pointcut(EntityManager manager): call(* AccountDao.setEntityManager(EntityManger)) && args(manager);

Is there any place I may go wrong? I test to move the .aj files and compile .java source. Everthing works fine. I am confused.

I appreciate any suggestion.

Thank you very much.

Mark Cooke-6 wrote:

Hi,
It's been a while since I've used AspectJ in anger but as no-one else has replied yet...

I'd say you probably want "args(manager)" instead of "target(manager)" in the obtainEntityManager pointcut.
The target of the call will be an AccountDAO, not an EntityManager.

See http://www.eclipse.org/aspectj/doc/released/progguide/semantics-joinPoints.html

HTH!
Mark.

--- On Wed, 4/11/09, neo anderson <[e-mail]> wrote:

> From: neo anderson <[e-mail]>
> Subject: [aspectj-users] A transaction question
> To: [e-mail]
> Date: Wednesday, 4 November, 2009, 12:09
>
> I am learning how to modulize transaction using aspectj,
> but encounter a
> problem that EntityManager I try to capture is always null.
> The compiler
> issues message saying that the advice can not be applied.
> as below:
>
> ... advice defined in example.AbstractTransaction has not
> been applied
> [Xlint:adviceDidNotMatch]
>
> What should I change so that I can capture the
> EntityManager while it is
> created (whilst calling to
> AccountDao.setEntityManager(..))?
>
> Thanks for help.
>
> Main.java
>
> package example;
>
> public class Main{
>     public static void main(String args[]){
>         Main m = new Main();
>         m.process();
>     }
>     void process(){
>         AccountDao dao = new
> AccountDao();
>    
> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>         User u = new
> User("1", "Smith");
>         u.setAddress("123
> Test Road, London.");
>         dao.save(u);
>
>        
> dao.list();   
>     }
> }
>
> AccountDao.java
>
> package example;
>
> import java.util.List;
> import java.util.ArrayList;
>
>
> public class AccountDao{
>
>     private EntityManager manager;
>
>     private static List<User> database
> = new ArrayList<User>();
>
>     public void
> setEntityManager(EntityManager manager){
>         this.manager =
> manager;
>     }   
>
>     public void save(User user){
>        
> database.add(user);   
>     }
>
>     public void list(){
>         for(User u :
> database){
>            
> System.out.println(">>>[AccountDao.java]"+u);   
>
>         }
>     }
> }
>
> User.java
>
> package example;
>
> public class User{
>     private String id;
>     private String name;
>     private String address;
>     public User(String id, String name){
>         this.id = id;
>         this.name = name;
>     }
>
>     public String getId(){
>         return this.id;
>     }
>
>     public String getName(){
>         return this.name;
>     }
>
>     public String getAddress(){
>         return this.address;
>     }
>
>     public void setAddress(String address){
>         this.address =
> address;
>     }
>
>     public String toString(){
>         return "<User
> [id:"+id+"][name:"+name+"][address:"+address+"]>";
>     }
> }
>
>
> PersistenceCreator.java
>
> package example;
>
> public class PersistenceCreator{
>     private static EntityManagerFactory
> factory;
>
>     public static EntityManagerFactory
> createEntityManagerFactory(){
>         if(null == factory)
>            
> factory = new EntityManagerFactory();
>         return factory;
>     }
> }
>
> EntityManagerFactory.java
>
> package example;
>
> public class EntityManagerFactory{
>
>     private static EntityManager manager;
>
>     public static EntityManager
> createEntityManager(){
>         if(null == manager){
>            
> manager = new EntityManager();
>         }
>         return manager;
>     }
> }
>
> EntityManager.java
>
> package example;
>
> public class EntityManager{
> }
>
> AbstractTransaction.aj
>
> package example;
>
> public abstract aspect AbstractTransaction
> percflow(scope()){
>
>     private EntityManager manager;
>    
>     protected abstract pointcut tx();
>
>     protected pointcut
> obtainEntityManager(EntityManager manager): call(*
> example.AccountDao.setEntityManager(EntityManager))
> && target(manager);
>
>     protected pointcut scope(): tx()
> && !cflowbelow(tx());
>
>     Object around(): scope(){
>        
> System.out.println("EntityManager:"+manager);// always null
>
>         Object result =
> proceed();
>         return result;
>     }
>
>     EntityManager around(EntityManager
> manager): obtainEntityManager(manager)
> && cflow(tx()){
>         if(null == manager){
>            
> manager = proceed(manager);
>        
>         }

>         return manager;
>     }
> }
>
> AccountTransaction.aj
>
> package example;
>
> public aspect AccountTransaction extends
> AbstractTransaction{
>
>     protected pointcut tx(): execution(*
> example.Main.process());
> }
> --
> View this message in context: http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
> Sent from the AspectJ - users mailing list archive at
> Nabble.com.
>
> _______________________________________________
> aspectj-users mailing list
> [e-mail]
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>



_______________________________________________
aspectj-users mailing list
[e-mail]
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[Andy Clement]

The method you are intercepting (setEntityManager) has a void return
type, so your advice should too.  The proceed() call you are using
will ensure your replacement is passed to the setEntityManager call.

Andy

2009/11/4 neo anderson <javadeveloper999@...>:

>
> Hi Mark & Andy. Thanks for your reply. I really appreciate your help.
>
> I change to use args, but now it thorws message:
>
> [error] incompatible return type applying to method-call(void
> example.AccountDao.setEntityManager(example.EntityManager))
>
> [error] incompatible return type applying to method-call(void
> example.AccountDao.setEntityManager(example.EntityManager))
> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>
> [warning] advice defined in example.AbstractTransaction has not been applied
> [Xlint:adviceDidNotMatch]
>
> I check the syntax and read the example in e.g.
> http://books.google.com.tw/books?id=AKuBlJGl7iUC&pg=PA54&lpg=PA54&dq=aspectj+call+args&source=bl&ots=58KGnyCZiN&sig=5gNdHoekFrDXJne3pVe6UO5tiYQ&hl=zh-TW&ei=kNbxSqTEBumgjAfdnp2WAQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CB0Q6AEwBQ#v=onepage&q=4-2%20capturing%20the%20parameter%20values%20passed%20on%20a%20method%20call&f=false
>
> The way to capture the EntityManager looks correct.
>
> public pointcut(EntityManager manager): call(*
> AccountDao.setEntityManager(EntityManger)) && args(manager);
>
> Is there any place I may go wrong? I test to move the .aj files and compile
> .java source. Everthing works fine. I am confused.
>
> I appreciate any suggestion.
>
> Thank you very much.
>
>
> Mark Cooke-6 wrote:
>>
>> Hi,
>> It's been a while since I've used AspectJ in anger but as no-one else has
>> replied yet...
>>
>> I'd say you probably want "args(manager)" instead of "target(manager)" in
>> the obtainEntityManager pointcut.
>> The target of the call will be an AccountDAO, not an EntityManager.
>>
>> See
>> http://www.eclipse.org/aspectj/doc/released/progguide/semantics-joinPoints.html
>>
>> HTH!
>> Mark.
>>
>> --- On Wed, 4/11/09, neo anderson <javadeveloper999@...> wrote:
>>
>>> From: neo anderson <javadeveloper999@...>
>>> Subject: [aspectj-users] A transaction question
>>> To: aspectj-users@...
>>> Date: Wednesday, 4 November, 2009, 12:09
>>>
>>> I am learning how to modulize transaction using aspectj,
>>> but encounter a
>>> problem that EntityManager I try to capture is always null.
>>> The compiler
>>> issues message saying that the advice can not be applied.
>>> as below:
>>>
>>> ... advice defined in example.AbstractTransaction has not
>>> been applied
>>> [Xlint:adviceDidNotMatch]
>>>
>>> What should I change so that I can capture the
>>> EntityManager while it is
>>> created (whilst calling to
>>> AccountDao.setEntityManager(..))?
>>>
>>> Thanks for help.
>>>
>>> Main.java
>>>
>>> package example;
>>>
>>> public class Main{
>>>     public static void main(String args[]){
>>>         Main m = new Main();
>>>         m.process();
>>>     }
>>>     void process(){
>>>         AccountDao dao = new
>>> AccountDao();
>>>
>>> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>>>         User u = new
>>> User("1", "Smith");
>>>         u.setAddress("123
>>> Test Road, London.");
>>>         dao.save(u);
>>>
>>>
>>> dao.list();
>>>     }
>>> }
>>>
>>> AccountDao.java
>>>
>>> package example;
>>>
>>> import java.util.List;
>>> import java.util.ArrayList;
>>>
>>>
>>> public class AccountDao{
>>>
>>>     private EntityManager manager;
>>>
>>>     private static List<User> database
>>> = new ArrayList<User>();
>>>
>>>     public void
>>> setEntityManager(EntityManager manager){
>>>         this.manager =
>>> manager;
>>>     }
>>>
>>>     public void save(User user){
>>>
>>> database.add(user);
>>>     }
>>>
>>>     public void list(){
>>>         for(User u :
>>> database){
>>>
>>> System.out.println(">>>[AccountDao.java]"+u);
>>>
>>>         }
>>>     }
>>> }
>>>
>>> User.java
>>>
>>> package example;
>>>
>>> public class User{
>>>     private String id;
>>>     private String name;
>>>     private String address;
>>>     public User(String id, String name){
>>>         this.id = id;
>>>         this.name = name;
>>>     }
>>>
>>>     public String getId(){
>>>         return this.id;
>>>     }
>>>
>>>     public String getName(){
>>>         return this.name;
>>>     }
>>>
>>>     public String getAddress(){
>>>         return this.address;
>>>     }
>>>
>>>     public void setAddress(String address){
>>>         this.address =
>>> address;
>>>     }
>>>
>>>     public String toString(){
>>>         return "<User
>>> [id:"+id+"][name:"+name+"][address:"+address+"]>";
>>>     }
>>> }
>>>
>>>
>>> PersistenceCreator.java
>>>
>>> package example;
>>>
>>> public class PersistenceCreator{
>>>     private static EntityManagerFactory
>>> factory;
>>>
>>>     public static EntityManagerFactory
>>> createEntityManagerFactory(){
>>>         if(null == factory)
>>>
>>> factory = new EntityManagerFactory();
>>>         return factory;
>>>     }
>>> }
>>>
>>> EntityManagerFactory.java
>>>
>>> package example;
>>>
>>> public class EntityManagerFactory{
>>>
>>>     private static EntityManager manager;
>>>
>>>     public static EntityManager
>>> createEntityManager(){
>>>         if(null == manager){
>>>
>>> manager = new EntityManager();
>>>         }
>>>         return manager;
>>>     }
>>> }
>>>
>>> EntityManager.java
>>>
>>> package example;
>>>
>>> public class EntityManager{
>>> }
>>>
>>> AbstractTransaction.aj
>>>
>>> package example;
>>>
>>> public abstract aspect AbstractTransaction
>>> percflow(scope()){
>>>
>>>     private EntityManager manager;
>>>
>>>     protected abstract pointcut tx();
>>>
>>>     protected pointcut
>>> obtainEntityManager(EntityManager manager): call(*
>>> example.AccountDao.setEntityManager(EntityManager))
>>> && target(manager);
>>>
>>>     protected pointcut scope(): tx()
>>> && !cflowbelow(tx());
>>>
>>>     Object around(): scope(){
>>>
>>> System.out.println("EntityManager:"+manager);// always null
>>>
>>>         Object result =
>>> proceed();
>>>         return result;
>>>     }
>>>
>>>     EntityManager around(EntityManager
>>> manager): obtainEntityManager(manager)
>>> && cflow(tx()){
>>>         if(null == manager){
>>>
>>> manager = proceed(manager);
>>>
>>>         }
>>
>>>         return manager;
>>>     }
>>> }
>>>
>>> AccountTransaction.aj
>>>
>>> package example;
>>>
>>> public aspect AccountTransaction extends
>>> AbstractTransaction{
>>>
>>>     protected pointcut tx(): execution(*
>>> example.Main.process());
>>> }
>>> --
>>> View this message in context:
>>> http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
>>> Sent from the AspectJ - users mailing list archive at
>>> Nabble.com.
>>>
>>> _______________________________________________
>>> aspectj-users mailing list
>>> aspectj-users@...
>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>>
>>
>>
>>
>> _______________________________________________
>> aspectj-users mailing list
>> aspectj-users@...
>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>
>>
>
> --
> View this message in context: http://old.nabble.com/A-transaction-question-tp26195112p26203290.html
> Sent from the AspectJ - users mailing list archive at Nabble.com.
>
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@...
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>

_______________________________________________
aspectj-users mailing list
aspectj-users@...
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[neo anderson]

Thank you very much. Now I am able to obtain EntityManager whilst method setEntityManager get called.

But a new question: how can I assign the captured variable e.g. EntityManager to the variable in an Aspect? For instance,

... aspect AbstractionTransaction ...{
        private EntityManager manager;
        void around(EntityManager manager): obtainEntityManager(manager) && cflow(tx()){
System.out.println("manager:"+manager); // manager instance is not null
                this.manager = manager; // but assign to the member of aspect seemingly does not work

                proceed(manager);
        }

}

My AbstractTransaction aspect contains a variable manager and I would like to assign when the setEntityManager get called. Because in the example of Aspectj in Action, the method intercepted will return Connection, which is different from the method I have. Is there any chance to assign the variable so that I can apply entitymanager to the pointcut when scope() is executed? Or what is the right way to do this?

       Object around(): scope(){
System.out.println("===========> EntityManager:"+manager); // after assigned, it is still null
                Object result = proceed();
                return result;
        }

Sorry if this question is too newbie. I search on the internet and read again the book Aspectj in Action, but seems there is no such explain.

Thanks for patiently answer my question.

I appreciate it.

Andy Clement wrote:

The method you are intercepting (setEntityManager) has a void return
type, so your advice should too.  The proceed() call you are using
will ensure your replacement is passed to the setEntityManager call.

Andy

2009/11/4 neo anderson <[e-mail]>:
>
> Hi Mark & Andy. Thanks for your reply. I really appreciate your help.
>
> I change to use args, but now it thorws message:
>
> [error] incompatible return type applying to method-call(void
> example.AccountDao.setEntityManager(example.EntityManager))
>
> [error] incompatible return type applying to method-call(void
> example.AccountDao.setEntityManager(example.EntityManager))
> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>
> [warning] advice defined in example.AbstractTransaction has not been applied
> [Xlint:adviceDidNotMatch]
>
> I check the syntax and read the example in e.g.
> http://books.google.com.tw/books?id=AKuBlJGl7iUC&pg=PA54&lpg=PA54&dq=aspectj+call+args&source=bl&ots=58KGnyCZiN&sig=5gNdHoekFrDXJne3pVe6UO5tiYQ&hl=zh-TW&ei=kNbxSqTEBumgjAfdnp2WAQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CB0Q6AEwBQ#v=onepage&q=4-2%20capturing%20the%20parameter%20values%20passed%20on%20a%20method%20call&f=false
>
> The way to capture the EntityManager looks correct.
>
> public pointcut(EntityManager manager): call(*
> AccountDao.setEntityManager(EntityManger)) && args(manager);
>
> Is there any place I may go wrong? I test to move the .aj files and compile
> .java source. Everthing works fine. I am confused.
>
> I appreciate any suggestion.
>
> Thank you very much.
>
>
> Mark Cooke-6 wrote:
>>
>> Hi,
>> It's been a while since I've used AspectJ in anger but as no-one else has
>> replied yet...
>>
>> I'd say you probably want "args(manager)" instead of "target(manager)" in
>> the obtainEntityManager pointcut.
>> The target of the call will be an AccountDAO, not an EntityManager.
>>
>> See
>> http://www.eclipse.org/aspectj/doc/released/progguide/semantics-joinPoints.html
>>
>> HTH!
>> Mark.
>>
>> --- On Wed, 4/11/09, neo anderson <[e-mail]> wrote:
>>
>>> From: neo anderson <[e-mail]>
>>> Subject: [aspectj-users] A transaction question
>>> To: [e-mail]
>>> Date: Wednesday, 4 November, 2009, 12:09
>>>
>>> I am learning how to modulize transaction using aspectj,
>>> but encounter a
>>> problem that EntityManager I try to capture is always null.
>>> The compiler
>>> issues message saying that the advice can not be applied.
>>> as below:
>>>
>>> ... advice defined in example.AbstractTransaction has not
>>> been applied
>>> [Xlint:adviceDidNotMatch]
>>>
>>> What should I change so that I can capture the
>>> EntityManager while it is
>>> created (whilst calling to
>>> AccountDao.setEntityManager(..))?
>>>
>>> Thanks for help.
>>>
>>> Main.java
>>>
>>> package example;
>>>
>>> public class Main{
>>>     public static void main(String args[]){
>>>         Main m = new Main();
>>>         m.process();
>>>     }
>>>     void process(){
>>>         AccountDao dao = new
>>> AccountDao();
>>>
>>> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>>>         User u = new
>>> User("1", "Smith");
>>>         u.setAddress("123
>>> Test Road, London.");
>>>         dao.save(u);
>>>
>>>
>>> dao.list();
>>>     }
>>> }
>>>
>>> AccountDao.java
>>>
>>> package example;
>>>
>>> import java.util.List;
>>> import java.util.ArrayList;
>>>
>>>
>>> public class AccountDao{
>>>
>>>     private EntityManager manager;
>>>
>>>     private static List<User> database
>>> = new ArrayList<User>();
>>>
>>>     public void
>>> setEntityManager(EntityManager manager){
>>>         this.manager =
>>> manager;
>>>     }
>>>
>>>     public void save(User user){
>>>
>>> database.add(user);
>>>     }
>>>
>>>     public void list(){
>>>         for(User u :
>>> database){
>>>
>>> System.out.println(">>>[AccountDao.java]"+u);
>>>
>>>         }
>>>     }
>>> }
>>>
>>> User.java
>>>
>>> package example;
>>>
>>> public class User{
>>>     private String id;
>>>     private String name;
>>>     private String address;
>>>     public User(String id, String name){
>>>         this.id = id;
>>>         this.name = name;
>>>     }
>>>
>>>     public String getId(){
>>>         return this.id;
>>>     }
>>>
>>>     public String getName(){
>>>         return this.name;
>>>     }
>>>
>>>     public String getAddress(){
>>>         return this.address;
>>>     }
>>>
>>>     public void setAddress(String address){
>>>         this.address =
>>> address;
>>>     }
>>>
>>>     public String toString(){
>>>         return "<User
>>> [id:"+id+"][name:"+name+"][address:"+address+"]>";
>>>     }
>>> }
>>>
>>>
>>> PersistenceCreator.java
>>>
>>> package example;
>>>
>>> public class PersistenceCreator{
>>>     private static EntityManagerFactory
>>> factory;
>>>
>>>     public static EntityManagerFactory
>>> createEntityManagerFactory(){
>>>         if(null == factory)
>>>
>>> factory = new EntityManagerFactory();
>>>         return factory;
>>>     }
>>> }
>>>
>>> EntityManagerFactory.java
>>>
>>> package example;
>>>
>>> public class EntityManagerFactory{
>>>
>>>     private static EntityManager manager;
>>>
>>>     public static EntityManager
>>> createEntityManager(){
>>>         if(null == manager){
>>>
>>> manager = new EntityManager();
>>>         }
>>>         return manager;
>>>     }
>>> }
>>>
>>> EntityManager.java
>>>
>>> package example;
>>>
>>> public class EntityManager{
>>> }
>>>
>>> AbstractTransaction.aj
>>>
>>> package example;
>>>
>>> public abstract aspect AbstractTransaction
>>> percflow(scope()){
>>>
>>>     private EntityManager manager;
>>>
>>>     protected abstract pointcut tx();
>>>
>>>     protected pointcut
>>> obtainEntityManager(EntityManager manager): call(*
>>> example.AccountDao.setEntityManager(EntityManager))
>>> && target(manager);
>>>
>>>     protected pointcut scope(): tx()
>>> && !cflowbelow(tx());
>>>
>>>     Object around(): scope(){
>>>
>>> System.out.println("EntityManager:"+manager);// always null
>>>
>>>         Object result =
>>> proceed();
>>>         return result;
>>>     }
>>>
>>>     EntityManager around(EntityManager
>>> manager): obtainEntityManager(manager)
>>> && cflow(tx()){
>>>         if(null == manager){
>>>
>>> manager = proceed(manager);
>>>
>>>         }
>>
>>>         return manager;
>>>     }
>>> }
>>>
>>> AccountTransaction.aj
>>>
>>> package example;
>>>
>>> public aspect AccountTransaction extends
>>> AbstractTransaction{
>>>
>>>     protected pointcut tx(): execution(*
>>> example.Main.process());
>>> }
>>> --
>>> View this message in context:
>>> http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
>>> Sent from the AspectJ - users mailing list archive at
>>> Nabble.com.
>>>
>>> _______________________________________________
>>> aspectj-users mailing list
>>> [e-mail]
>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>>
>>
>>
>>
>> _______________________________________________
>> aspectj-users mailing list
>> [e-mail]
>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>
>>
>
> --
> View this message in context: http://old.nabble.com/A-transaction-question-tp26195112p26203290.html
> Sent from the AspectJ - users mailing list archive at Nabble.com.
>
> _______________________________________________
> aspectj-users mailing list
> [e-mail]
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>
_______________________________________________
aspectj-users mailing list
[e-mail]
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[Simone Gianni-2]

Hi Neo,
it should work, if you don't find the manager there it could be because
two different instances of AbstractTransaction aspect are intercepting
the two methods. This happens if you declared your aspect with a
specific instantiation rule.

By default, aspects are singletons. That means that there will be only
one instance of AbstractTransaction in your application (well, in your
classloader). Since this is sometimes a limit, AspectJ supports
different instantiation systems, like perthis, pertarget, percflow
etc... If you use one of these construct, then a new instance of your
aspect will be created for each "this", each "target" etc.. in this
case, when you use this.manager inside your aspect, it could be null
cause it is actually a different instance.

Could you post the complete aspect declaration, so that we can see which
instantiation rule you are using?


Hope this helps,
Simone

neo anderson wrote:

> Thank you very much. Now I am able to obtain EntityManager whilst method
> setEntityManager get called.
>
> But a new question: how can I assign the captured variable e.g.
> EntityManager to the variable in an Aspect? For instance,
>
> ... aspect AbstractionTransaction ...{
>         private EntityManager manager;
>         void around(EntityManager manager): obtainEntityManager(manager) &&
> cflow(tx()){
> System.out.println("manager:"+manager); // manager instance is not null
>                 this.manager = manager; // but assign to the member of
> aspect seemingly does not work
>
>                 proceed(manager);
>         }
>
> }
>
> My AbstractTransaction aspect contains a variable manager and I would like
> to assign when the setEntityManager get called. Because in the example of
> Aspectj in Action, the method intercepted will return Connection, which is
> different from the method I have. Is there any chance to assign the variable
> so that I can apply entitymanager to the pointcut when scope() is executed?
> Or what is the right way to do this?
>
>        Object around(): scope(){
> System.out.println("===========> EntityManager:"+manager); // after
> assigned, it is still null
>                 Object result = proceed();
>                 return result;
>         }
>
> Sorry if this question is too newbie. I search on the internet and read
> again the book Aspectj in Action, but seems there is no such explain.
>
> Thanks for patiently answer my question.
>
> I appreciate it.
>
>
>
>
> Andy Clement wrote:
>  
>> The method you are intercepting (setEntityManager) has a void return
>> type, so your advice should too.  The proceed() call you are using
>> will ensure your replacement is passed to the setEntityManager call.
>>
>> Andy
>>
>> 2009/11/4 neo anderson <javadeveloper999@...>:
>>    
>>> Hi Mark & Andy. Thanks for your reply. I really appreciate your help.
>>>
>>> I change to use args, but now it thorws message:
>>>
>>> [error] incompatible return type applying to method-call(void
>>> example.AccountDao.setEntityManager(example.EntityManager))
>>>
>>> [error] incompatible return type applying to method-call(void
>>> example.AccountDao.setEntityManager(example.EntityManager))
>>> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>>>
>>> [warning] advice defined in example.AbstractTransaction has not been
>>> applied
>>> [Xlint:adviceDidNotMatch]
>>>
>>> I check the syntax and read the example in e.g.
>>> http://books.google.com.tw/books?id=AKuBlJGl7iUC&pg=PA54&lpg=PA54&dq=aspectj+call+args&source=bl&ots=58KGnyCZiN&sig=5gNdHoekFrDXJne3pVe6UO5tiYQ&hl=zh-TW&ei=kNbxSqTEBumgjAfdnp2WAQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CB0Q6AEwBQ#v=onepage&q=4-2%20capturing%20the%20parameter%20values%20passed%20on%20a%20method%20call&f=false
>>>
>>> The way to capture the EntityManager looks correct.
>>>
>>> public pointcut(EntityManager manager): call(*
>>> AccountDao.setEntityManager(EntityManger)) && args(manager);
>>>
>>> Is there any place I may go wrong? I test to move the .aj files and
>>> compile
>>> .java source. Everthing works fine. I am confused.
>>>
>>> I appreciate any suggestion.
>>>
>>> Thank you very much.
>>>
>>>
>>> Mark Cooke-6 wrote:
>>>      
>>>> Hi,
>>>> It's been a while since I've used AspectJ in anger but as no-one else
>>>> has
>>>> replied yet...
>>>>
>>>> I'd say you probably want "args(manager)" instead of "target(manager)"
>>>> in
>>>> the obtainEntityManager pointcut.
>>>> The target of the call will be an AccountDAO, not an EntityManager.
>>>>
>>>> See
>>>> http://www.eclipse.org/aspectj/doc/released/progguide/semantics-joinPoints.html
>>>>
>>>> HTH!
>>>> Mark.
>>>>
>>>> --- On Wed, 4/11/09, neo anderson <javadeveloper999@...> wrote:
>>>>
>>>>        
>>>>> From: neo anderson <javadeveloper999@...>
>>>>> Subject: [aspectj-users] A transaction question
>>>>> To: aspectj-users@...
>>>>> Date: Wednesday, 4 November, 2009, 12:09
>>>>>
>>>>> I am learning how to modulize transaction using aspectj,
>>>>> but encounter a
>>>>> problem that EntityManager I try to capture is always null.
>>>>> The compiler
>>>>> issues message saying that the advice can not be applied.
>>>>> as below:
>>>>>
>>>>> ... advice defined in example.AbstractTransaction has not
>>>>> been applied
>>>>> [Xlint:adviceDidNotMatch]
>>>>>
>>>>> What should I change so that I can capture the
>>>>> EntityManager while it is
>>>>> created (whilst calling to
>>>>> AccountDao.setEntityManager(..))?
>>>>>
>>>>> Thanks for help.
>>>>>
>>>>> Main.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class Main{
>>>>>     public static void main(String args[]){
>>>>>         Main m = new Main();
>>>>>         m.process();
>>>>>     }
>>>>>     void process(){
>>>>>         AccountDao dao = new
>>>>> AccountDao();
>>>>>
>>>>> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>>>>>         User u = new
>>>>> User("1", "Smith");
>>>>>         u.setAddress("123
>>>>> Test Road, London.");
>>>>>         dao.save(u);
>>>>>
>>>>>
>>>>> dao.list();
>>>>>     }
>>>>> }
>>>>>
>>>>> AccountDao.java
>>>>>
>>>>> package example;
>>>>>
>>>>> import java.util.List;
>>>>> import java.util.ArrayList;
>>>>>
>>>>>
>>>>> public class AccountDao{
>>>>>
>>>>>     private EntityManager manager;
>>>>>
>>>>>     private static List<User> database
>>>>> = new ArrayList<User>();
>>>>>
>>>>>     public void
>>>>> setEntityManager(EntityManager manager){
>>>>>         this.manager =
>>>>> manager;
>>>>>     }
>>>>>
>>>>>     public void save(User user){
>>>>>
>>>>> database.add(user);
>>>>>     }
>>>>>
>>>>>     public void list(){
>>>>>         for(User u :
>>>>> database){
>>>>>
>>>>> System.out.println(">>>[AccountDao.java]"+u);
>>>>>
>>>>>         }
>>>>>     }
>>>>> }
>>>>>
>>>>> User.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class User{
>>>>>     private String id;
>>>>>     private String name;
>>>>>     private String address;
>>>>>     public User(String id, String name){
>>>>>         this.id = id;
>>>>>         this.name = name;
>>>>>     }
>>>>>
>>>>>     public String getId(){
>>>>>         return this.id;
>>>>>     }
>>>>>
>>>>>     public String getName(){
>>>>>         return this.name;
>>>>>     }
>>>>>
>>>>>     public String getAddress(){
>>>>>         return this.address;
>>>>>     }
>>>>>
>>>>>     public void setAddress(String address){
>>>>>         this.address =
>>>>> address;
>>>>>     }
>>>>>
>>>>>     public String toString(){
>>>>>         return "<User
>>>>> [id:"+id+"][name:"+name+"][address:"+address+"]>";
>>>>>     }
>>>>> }
>>>>>
>>>>>
>>>>> PersistenceCreator.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class PersistenceCreator{
>>>>>     private static EntityManagerFactory
>>>>> factory;
>>>>>
>>>>>     public static EntityManagerFactory
>>>>> createEntityManagerFactory(){
>>>>>         if(null == factory)
>>>>>
>>>>> factory = new EntityManagerFactory();
>>>>>         return factory;
>>>>>     }
>>>>> }
>>>>>
>>>>> EntityManagerFactory.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class EntityManagerFactory{
>>>>>
>>>>>     private static EntityManager manager;
>>>>>
>>>>>     public static EntityManager
>>>>> createEntityManager(){
>>>>>         if(null == manager){
>>>>>
>>>>> manager = new EntityManager();
>>>>>         }
>>>>>         return manager;
>>>>>     }
>>>>> }
>>>>>
>>>>> EntityManager.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class EntityManager{
>>>>> }
>>>>>
>>>>> AbstractTransaction.aj
>>>>>
>>>>> package example;
>>>>>
>>>>> public abstract aspect AbstractTransaction
>>>>> percflow(scope()){
>>>>>
>>>>>     private EntityManager manager;
>>>>>
>>>>>     protected abstract pointcut tx();
>>>>>
>>>>>     protected pointcut
>>>>> obtainEntityManager(EntityManager manager): call(*
>>>>> example.AccountDao.setEntityManager(EntityManager))
>>>>> && target(manager);
>>>>>
>>>>>     protected pointcut scope(): tx()
>>>>> && !cflowbelow(tx());
>>>>>
>>>>>     Object around(): scope(){
>>>>>
>>>>> System.out.println("EntityManager:"+manager);// always null
>>>>>
>>>>>         Object result =
>>>>> proceed();
>>>>>         return result;
>>>>>     }
>>>>>
>>>>>     EntityManager around(EntityManager
>>>>> manager): obtainEntityManager(manager)
>>>>> && cflow(tx()){
>>>>>         if(null == manager){
>>>>>
>>>>> manager = proceed(manager);
>>>>>
>>>>>         }
>>>>>          
>>>>>         return manager;
>>>>>     }
>>>>> }
>>>>>
>>>>> AccountTransaction.aj
>>>>>
>>>>> package example;
>>>>>
>>>>> public aspect AccountTransaction extends
>>>>> AbstractTransaction{
>>>>>
>>>>>     protected pointcut tx(): execution(*
>>>>> example.Main.process());
>>>>> }
>>>>> --
>>>>> View this message in context:
>>>>> http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
>>>>> Sent from the AspectJ - users mailing list archive at
>>>>> Nabble.com.
>>>>>
>>>>> _______________________________________________
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Simone Gianni            CEO Semeru s.r.l.           Apache Committer
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[neo anderson]

The code is as below. The Main class is the starting point. AbstracTransaction is the aspect to capture EntityManager instance, which will create transaction covering the method executed e.g. process().

It seems like the the advice of `obtainEntityManager(..)&&cflow(..)' is not executed because the terminal does not output related information.

Whilst reading the AspectJ in Action, the percflow indicates that per-control-flow will create a new instance. So I suppose the specified percflow(scope()) would only cause an aspect  instance created (because in the Main class process() is only executed once), wouldn't it?

Thanks for your help.

I appreciate it.

package example;

public abstract aspect AbstractTransaction percflow(scope()){

        private EntityManager manager;
       
        protected abstract pointcut tx(); // concreated joint point specified in AccountTransaction.aj

        protected pointcut obtainEntityManager(EntityManager manager): call(public void example.AccountDao.setEntityManager(EntityManager)) && args(manager) ;

        protected pointcut scope(): tx() && !cflowbelow(tx());

        Object around(): scope(){
System.out.println("===========> EntityManager:"+manager); // null
                Object result = proceed();
                return result;
        }

       
        void around(EntityManager manager): obtainEntityManager(manager) && cflow(tx()){
                this.manager = manager;
System.out.println(">>>>>>>>>>>>>>>  EntityManager:"+this.manager); // seems not run because console does not print anything related to this line.
                proceed(manager);
        }
}

//  concrete class specifying the join point to be captured.
package example;

public aspect AccountTransaction extends AbstractTransaction{

        protected pointcut tx(): execution(* example.Main.process());
}

// main class want to be monitored
package example;

import example.EntityManager;

public class Main{
        private AccountDao dao;
        public static void main(String args[]){
                AccountDao d = new AccountDao();
                d.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
                Main m = new Main(d);
                m.process();
                m.print();
        }

        public Main(AccountDao dao){
                this.dao = dao;
        }

        void process(){
                User u = new User("1", "Smith");
                u.setAddress("7 Unkown Road, London, U.K.");
                dao.save(u);
        }
        void print(){
                dao.list();
        }
}

Simone Gianni-2 wrote:

Hi Neo,
it should work, if you don't find the manager there it could be because
two different instances of AbstractTransaction aspect are intercepting
the two methods. This happens if you declared your aspect with a
specific instantiation rule.

By default, aspects are singletons. That means that there will be only
one instance of AbstractTransaction in your application (well, in your
classloader). Since this is sometimes a limit, AspectJ supports
different instantiation systems, like perthis, pertarget, percflow
etc... If you use one of these construct, then a new instance of your
aspect will be created for each "this", each "target" etc.. in this
case, when you use this.manager inside your aspect, it could be null
cause it is actually a different instance.

Could you post the complete aspect declaration, so that we can see which
instantiation rule you are using?


Hope this helps,
Simone

neo anderson wrote:
> Thank you very much. Now I am able to obtain EntityManager whilst method
> setEntityManager get called.
>
> But a new question: how can I assign the captured variable e.g.
> EntityManager to the variable in an Aspect? For instance,
>
> ... aspect AbstractionTransaction ...{
>         private EntityManager manager;
>         void around(EntityManager manager): obtainEntityManager(manager) &&
> cflow(tx()){
> System.out.println("manager:"+manager); // manager instance is not null
>                 this.manager = manager; // but assign to the member of
> aspect seemingly does not work
>
>                 proceed(manager);
>         }
>
> }
>
> My AbstractTransaction aspect contains a variable manager and I would like
> to assign when the setEntityManager get called. Because in the example of
> Aspectj in Action, the method intercepted will return Connection, which is
> different from the method I have. Is there any chance to assign the variable
> so that I can apply entitymanager to the pointcut when scope() is executed?
> Or what is the right way to do this?
>
>        Object around(): scope(){
> System.out.println("===========> EntityManager:"+manager); // after
> assigned, it is still null
>                 Object result = proceed();
>                 return result;
>         }
>
> Sorry if this question is too newbie. I search on the internet and read
> again the book Aspectj in Action, but seems there is no such explain.
>
> Thanks for patiently answer my question.
>
> I appreciate it.
>
>
>
>
> Andy Clement wrote:
>  
>> The method you are intercepting (setEntityManager) has a void return
>> type, so your advice should too.  The proceed() call you are using
>> will ensure your replacement is passed to the setEntityManager call.
>>
>> Andy
>>
>> 2009/11/4 neo anderson <[e-mail]>:
>>    
>>> Hi Mark & Andy. Thanks for your reply. I really appreciate your help.
>>>
>>> I change to use args, but now it thorws message:
>>>
>>> [error] incompatible return type applying to method-call(void
>>> example.AccountDao.setEntityManager(example.EntityManager))
>>>
>>> [error] incompatible return type applying to method-call(void
>>> example.AccountDao.setEntityManager(example.EntityManager))
>>> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>>>
>>> [warning] advice defined in example.AbstractTransaction has not been
>>> applied
>>> [Xlint:adviceDidNotMatch]
>>>
>>> I check the syntax and read the example in e.g.
>>> http://books.google.com.tw/books?id=AKuBlJGl7iUC&pg=PA54&lpg=PA54&dq=aspectj+call+args&source=bl&ots=58KGnyCZiN&sig=5gNdHoekFrDXJne3pVe6UO5tiYQ&hl=zh-TW&ei=kNbxSqTEBumgjAfdnp2WAQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CB0Q6AEwBQ#v=onepage&q=4-2%20capturing%20the%20parameter%20values%20passed%20on%20a%20method%20call&f=false
>>>
>>> The way to capture the EntityManager looks correct.
>>>
>>> public pointcut(EntityManager manager): call(*
>>> AccountDao.setEntityManager(EntityManger)) && args(manager);
>>>
>>> Is there any place I may go wrong? I test to move the .aj files and
>>> compile
>>> .java source. Everthing works fine. I am confused.
>>>
>>> I appreciate any suggestion.
>>>
>>> Thank you very much.
>>>
>>>
>>> Mark Cooke-6 wrote:
>>>      
>>>> Hi,
>>>> It's been a while since I've used AspectJ in anger but as no-one else
>>>> has
>>>> replied yet...
>>>>
>>>> I'd say you probably want "args(manager)" instead of "target(manager)"
>>>> in
>>>> the obtainEntityManager pointcut.
>>>> The target of the call will be an AccountDAO, not an EntityManager.
>>>>
>>>> See
>>>> http://www.eclipse.org/aspectj/doc/released/progguide/semantics-joinPoints.html
>>>>
>>>> HTH!
>>>> Mark.
>>>>
>>>> --- On Wed, 4/11/09, neo anderson <[e-mail]> wrote:
>>>>
>>>>        
>>>>> From: neo anderson <[e-mail]>
>>>>> Subject: [aspectj-users] A transaction question
>>>>> To: [e-mail]
>>>>> Date: Wednesday, 4 November, 2009, 12:09
>>>>>
>>>>> I am learning how to modulize transaction using aspectj,
>>>>> but encounter a
>>>>> problem that EntityManager I try to capture is always null.
>>>>> The compiler
>>>>> issues message saying that the advice can not be applied.
>>>>> as below:
>>>>>
>>>>> ... advice defined in example.AbstractTransaction has not
>>>>> been applied
>>>>> [Xlint:adviceDidNotMatch]
>>>>>
>>>>> What should I change so that I can capture the
>>>>> EntityManager while it is
>>>>> created (whilst calling to
>>>>> AccountDao.setEntityManager(..))?
>>>>>
>>>>> Thanks for help.
>>>>>
>>>>> Main.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class Main{
>>>>>     public static void main(String args[]){
>>>>>         Main m = new Main();
>>>>>         m.process();
>>>>>     }
>>>>>     void process(){
>>>>>         AccountDao dao = new
>>>>> AccountDao();
>>>>>
>>>>> dao.setEntityManager(PersistenceCreator.createEntityManagerFactory().createEntityManager());
>>>>>         User u = new
>>>>> User("1", "Smith");
>>>>>         u.setAddress("123
>>>>> Test Road, London.");
>>>>>         dao.save(u);
>>>>>
>>>>>
>>>>> dao.list();
>>>>>     }
>>>>> }
>>>>>
>>>>> AccountDao.java
>>>>>
>>>>> package example;
>>>>>
>>>>> import java.util.List;
>>>>> import java.util.ArrayList;
>>>>>
>>>>>
>>>>> public class AccountDao{
>>>>>
>>>>>     private EntityManager manager;
>>>>>
>>>>>     private static List<User> database
>>>>> = new ArrayList<User>();
>>>>>
>>>>>     public void
>>>>> setEntityManager(EntityManager manager){
>>>>>         this.manager =
>>>>> manager;
>>>>>     }
>>>>>
>>>>>     public void save(User user){
>>>>>
>>>>> database.add(user);
>>>>>     }
>>>>>
>>>>>     public void list(){
>>>>>         for(User u :
>>>>> database){
>>>>>
>>>>> System.out.println(">>>[AccountDao.java]"+u);
>>>>>
>>>>>         }
>>>>>     }
>>>>> }
>>>>>
>>>>> User.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class User{
>>>>>     private String id;
>>>>>     private String name;
>>>>>     private String address;
>>>>>     public User(String id, String name){
>>>>>         this.id = id;
>>>>>         this.name = name;
>>>>>     }
>>>>>
>>>>>     public String getId(){
>>>>>         return this.id;
>>>>>     }
>>>>>
>>>>>     public String getName(){
>>>>>         return this.name;
>>>>>     }
>>>>>
>>>>>     public String getAddress(){
>>>>>         return this.address;
>>>>>     }
>>>>>
>>>>>     public void setAddress(String address){
>>>>>         this.address =
>>>>> address;
>>>>>     }
>>>>>
>>>>>     public String toString(){
>>>>>         return "<User
>>>>> [id:"+id+"][name:"+name+"][address:"+address+"]>";
>>>>>     }
>>>>> }
>>>>>
>>>>>
>>>>> PersistenceCreator.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class PersistenceCreator{
>>>>>     private static EntityManagerFactory
>>>>> factory;
>>>>>
>>>>>     public static EntityManagerFactory
>>>>> createEntityManagerFactory(){
>>>>>         if(null == factory)
>>>>>
>>>>> factory = new EntityManagerFactory();
>>>>>         return factory;
>>>>>     }
>>>>> }
>>>>>
>>>>> EntityManagerFactory.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class EntityManagerFactory{
>>>>>
>>>>>     private static EntityManager manager;
>>>>>
>>>>>     public static EntityManager
>>>>> createEntityManager(){
>>>>>         if(null == manager){
>>>>>
>>>>> manager = new EntityManager();
>>>>>         }
>>>>>         return manager;
>>>>>     }
>>>>> }
>>>>>
>>>>> EntityManager.java
>>>>>
>>>>> package example;
>>>>>
>>>>> public class EntityManager{
>>>>> }
>>>>>
>>>>> AbstractTransaction.aj
>>>>>
>>>>> package example;
>>>>>
>>>>> public abstract aspect AbstractTransaction
>>>>> percflow(scope()){
>>>>>
>>>>>     private EntityManager manager;
>>>>>
>>>>>     protected abstract pointcut tx();
>>>>>
>>>>>     protected pointcut
>>>>> obtainEntityManager(EntityManager manager): call(*
>>>>> example.AccountDao.setEntityManager(EntityManager))
>>>>> && target(manager);
>>>>>
>>>>>     protected pointcut scope(): tx()
>>>>> && !cflowbelow(tx());
>>>>>
>>>>>     Object around(): scope(){
>>>>>
>>>>> System.out.println("EntityManager:"+manager);// always null
>>>>>
>>>>>         Object result =
>>>>> proceed();
>>>>>         return result;
>>>>>     }
>>>>>
>>>>>     EntityManager around(EntityManager
>>>>> manager): obtainEntityManager(manager)
>>>>> && cflow(tx()){
>>>>>         if(null == manager){
>>>>>
>>>>> manager = proceed(manager);
>>>>>
>>>>>         }
>>>>>          
>>>>>         return manager;
>>>>>     }
>>>>> }
>>>>>
>>>>> AccountTransaction.aj
>>>>>
>>>>> package example;
>>>>>
>>>>> public aspect AccountTransaction extends
>>>>> AbstractTransaction{
>>>>>
>>>>>     protected pointcut tx(): execution(*
>>>>> example.Main.process());
>>>>> }
>>>>> --
>>>>> View this message in context:
>>>>> http://old.nabble.com/A-transaction-question-tp26195112p26195112.html
>>>>> Sent from the AspectJ - users mailing list archive at
>>>>> Nabble.com.
>>>>>
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http://www.simonegianni.it/

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