Alternatives to the Autocloseable trick

Transactions.java

// The current state:

try (BuyerDataState buyerDataState = this.notifyBuyerUpdateManager.beginAddressUpdate(buyer.getLegalEntityId())) {
    return buyerHandler.updateBuyer(buyer);
}

private static class NotifyBuyerUpdateManager {
  public static BuyerDataState beginAddressUpdate() {
    final BuyerData currentBuyerData = loadBuyerData();
    
    return new AutoCloseable() {
      @Override
      public void close() {
        final newBuyerData = loadBuyerData();
        if (!newBuyerData.equals(oldBuyerData)) {
          notifyBuyerDataChanged();
        }
      }
    }
  }
}





// -----------------------------------------------------------------------------
// Alternative #1:

return Transaction.execute(
      () -> loadBuyerData(),
      (unused) -> buyerHandler.updateBuyer(buyer),
      (previousBuyerData) -> {
          final BuyerData newBuyerData = loadBuyerData();
          if (!newBuyerData.equals(previousBuyerData)) {
              notifyBuyerDataChanged();
          }
      }
);

private static class Transaction {
    public static <Ctx, Ret> Ret execute(
        final Supplier<Ctx> context,
        final Function<Ctx, Ret> transaction,
        final Consumer<Ctx> then
    ) {
        final Ctx ctx = context.get();
        try {
            return transaction.apply(ctx);
        } finally {
            then.accept(ctx);
        }
    }
}





// -----------------------------------------------------------------------------
// Alternative #2:

final BuyerData currentBuyerData = loadBuyerData();
try {
    return buyerHandler.updateBuyer(buyer);
} finally {
    final BuyerData newBuyerData = loadBuyerData();
    if (!newBuyerData.equals(previousBuyerData)) {
        notifyBuyerDataChanged();
    }
}





// -----------------------------------------------------------------------------
// Alternative #3:

final BuyerData previousBuyerData = loadBuyerData();
final Buyer result = buyerHandler.updateBuyer(buyer);
final BuyerData newBuyerData = loadBuyerData();
if (!newBuyerData.equals(previousBuyerData)) {
    notifyBuyerDataChanged();
}

return result;





// -----------------------------------------------------------------------------
// Alternative #4:

final Buyer result = buyerHandler.updateBuyer(buyer);
notifyBuyerDataChanged();
return result;