Seam TransactionWorker API

Consumer.java

public class Consumer
{
   private static final String[] GAME_TITLES = {"Game 1", "Game 2"};
   
   @Inject
   private TransactionWorkExecutor txWorkExecutor;

   public void insertRecords()
   {
      txWorkExecutor.execute(new VoidTransactionWorker()
      {
         @Override public void doWorkInTransaction(TransactionContext ctx) throws Exception
         {
            for (String title : GAME_TITLES)
            {
               Game game = new Game(title);
               ctx.getEntityManager().persist(game);
            }
         }
      });
   }
}

TransactionContext.java

public class TransactionContext
{
   private SeamTransaction tx;
   private EntityManager em;
   
   public TransactionContext(final SeamTransaction tx, final EntityManager em)
   {
      this.tx = tx;
      this.em = em;
   }
      
   public EntityManager getEntityManager()
   {
      return em;
   }

   public SeamTransaction getTransaction()
   {
      return tx;
   }
}

TransactionWorker.java

public interface TransactionWorker<T>
{
   public T doWorkInTransactionAndReturn(TransactionContext ctx) throws Exception;
}

TransactionWorkExecutor.java

public class TransactionWorkExecutor
{     
   @Inject
   private EntityManager em;

   @Inject
   private SeamTransaction tx;
      
   public <T> T execute(TransactionWorker<T> worker) throws Exception
   {
      T result = null;
      try
      {
         tx.begin();         
         result = worker.doWorkInTransactionAndReturn(new TransactionContext(tx, em));
         tx.commit();
         return result;
      }
      catch (Exception e)
      {
         // perhaps more detailed checking here
         tx.rollback();
         throw e;
      }
   }
}

VoidTransactionWorker.java

public abstract class VoidTransactionWorker implements TransactionWorker<Void>
{
   @Override
   public Void doWorkInTransactionAndReturn(TransactionContext ctx) throws Exception
   {
      doWorkInTransaction(ctx);
      return null;
   }

   public abstract void doWorkInTransaction(TransactionContext ctx) throws Exception;
}