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Re: [aspectj-users] A transaction question
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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@xxxxxxxxxxx>:
>>
>> 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@xxxxxxxxxxx> wrote:
>>>
>>>> From: neo anderson <javadeveloper999@xxxxxxxxxxx>
>>>> Subject: [aspectj-users] A transaction question
>>>> To: aspectj-users@xxxxxxxxxxx
>>>> 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@xxxxxxxxxxx
>>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> aspectj-users mailing list
>>> aspectj-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>>
>>>
>>
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>>
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