DB query from bean

[John Schretz]

Is it ok and thread safe to call a static DAO method from a bean class?

I.E. Create a new cart object to be used in a servlet
then in that instance of cart make calls to the DB as ahown below.

Would this give me any problems?

   
Cart cart = new Cart()

Within cart class

 
DiscountNewUser newUserDiscI = DiscountDB.GetNewUserDiscount();
// do some stuff.....

[Ulf Dittmer]

No, that's not thread-safe, since servlets are multi-threaded. Unless you make provisions for it (e.g., synchronizing that code section in the servlet, or making DiscountDB.GetNewUserDiscount() thread-safe) the code can run into trouble.

[John Schretz]

Ulf Dittmer wrote:No, that's not thread-safe, since servlets are multi-threaded. Unless you make provisions for it (e.g., synchronizing that code section in the servlet, or making DiscountDB.GetNewUserDiscount() thread-safe) the code can run into trouble.

ok but i should be fine with executing DiscountDB.GetNewUserDiscount() right from the servlet then, correct?

[Bauke Scholtz]

Servlets are at its own multithreaded. It is a very bad idea to synchronize servlet requests.

So either remove that 'static' modifier of the DAO method --this makes indeed no sense--, or make sure that your DAO method is written threadsafe (no access to static variables and having only method variables).

[John Schretz]

Bauke Scholtz wrote:Servlets are at its own multithreaded. It is a very bad idea to synchronize servlet requests.

So either remove that 'static' modifier of the DAO method --this makes indeed no sense--, or make sure that your DAO method is written threadsafe (no access to static variables and having only method variables).

I have moved DiscountNewUser newUserDiscI = DiscountDB.GetNewUserDiscount(); into the servlet. All variables are are method variables. So im good now. thanks

[Ulf Dittmer]

I have moved DiscountNewUser newUserDiscI = DiscountDB.GetNewUserDiscount(); into the servlet. All variables are are method variables. So im good now.

... only if DiscountDB.GetNewUserDiscount is thread-safe. Otherwise there'll be trouble.

[Bauke Scholtz]

When he said " All variables are are method variables.", I think (and hope) that he actually meant the DB method.

[John Schretz]

Bauke Scholtz wrote:When he said " All variables are are method variables.", I think (and hope) that he actually meant the DB method.

Yes