Question

Environment: The application is using Spring Framework 2.5.6.SEC01 and iBatis 2.3.4.726. It is MVC design.

Here’s the scenario:

1. Input/update data from the client

2. Press Update button to submit

3. Process the data and execute DML (insert, update, delete)

4. Back the result to client and display the data

5. However, upon the page loaded, I need to call the API via Javascript (i have no control with the API, just need to pass the required parameter and check the result if SUCCESS or ERROR)

6. If API returns SUCCESS, nothing to do. But it returns ERROR, I give alert message to inform the user.

   I have View(client), Service and Data Access Layers. When the client do the submit (scenario #2), it enters the Service to process the data and automatically start Transaction (scenario #3). Automatically execute the commit upon exit to Service and back to client to show the data (scenario #4).

Problem: How can I suspend the transaction not to execute the commit, then back to client to call API via Javascript. When API returns SUCCESS, execute commit via Ajax (or other way) or in the other hand, rollback it.

Any guidance on the right direction is appreciated.

Answer 1

If I understand correctly, you want to start a database transaction, insert data (without comitting), keeping the connection and the transaction open, return to the client, and based on some javascript result, do a commit.

This feels like a strange design where the client can actually keep a connection open, making your application extremely vulnerable for (D)DOS attacks or client problems in general.

I would try really hard to remodel it as follows:

1. Upon submit, call the javascript you need to confirm the commit/save action
2. When the javascript succeeds, do the submit to your own server
3. Do normal Connection/Transaction handling within the DAO, not exposing transactions to the client.

This is quicker, more robust and also probably less code.