Maintaining Workflow State
Queue elements and pseudo-conversation requests are places places for persistent workflow state. Other examples:
- Browser cookies (files that are read/written by http requests), containing user profile information
- Shopping cart (in web server cache or database)
Such state management arises within a transaction too
- Server scans a file. Each time it hits a relevant record, return it.
- Issue: later calls must go to the same server, since only it knows where the transaction’s last call left off.
- Sol’n 1: keep state in the message (like pseudo-conversation)
- Sol’n 2: first call gets a binding handle to the server, so later calls go to it. Server needs to release state when client disappears