CODEWITHSUNDEEP
javahibernate
Ben G
Ben G

Reputation: 55

Example of using multiple transactions with same session

I am fairly new to Hibernate. I am trying to understand sessions and transactions using the example below. I have an event management system. I have an entity called Event, and a user can edit an Event. Should I save a session as an instance variable in the service class and use it to do multiple Transactions in different methods ? I also would like to use it as a cache. Where should session object be stored ? Or how to best achieve what I am trying to do below - I have two transactions - first will fetch as event object and second needs to edit it and save it to the database.

 ServiceClass {

     Session session ;

     Constructor () { 
         session = sessionFactory.getSession();
     }


     //First transaction

     public Event getEvent() {

        begin new Transaction on session.
           Fetch new Event object 
        End new transacton

        return event; //to display to user
     }

     //Second transaction 

     public void editEvent(String newName, Date newDate) { 

         begin Transaction
           Obtain the Event object from the session which was result of First transaction above
           event.setName(newName);   //This should be in persistent state and affect the database
           event.setDate(newDate);     
         end Transaction
      }


 }

Thank you so much in advance :)

Upvotes: 1

Views: 211

Answers (1)

Daniel Sagenschneider
Daniel Sagenschneider

Reputation: 73

You need to consider the session the transaction. If your ServiceClass is used in multi-threaded environment (such as Servlets) then specifying it in a field will cause threading issues. To avoid this problem, put the session creation in the editEvent() method, which should:

  1. Create the session
  2. Start transaction
  3. Retrieve entities from database via session
  4. Make changes to the entities
  5. Commit transaction

Upvotes: 1

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