Paul Andrew : Patterns for Long Running Activities in Windows Workflow Foundation
Have you ever noticed that long running operations are difficult to implement in software? Did you ever think about why that is the case?
Some kinds of long running operations are obviously difficult in software such as requesting approval of another person. You can’t implement this scenario in a single method. You have to send a message to the other person, save some state information and then wait for a response message. There are other software scenarios that have the same kinds of issues but are not so obviously long running such as a database operation or a web service call. Database operations will typically complete in a few tens of milliseconds, but sometimes they are much slower and can take many seconds. Synchronous web service calls are much less predictable and can take even longer… [continua alla fonte] …