2007/1/25, Tom Schneider <[EMAIL PROTECTED]>:
This is an issue with the typical edit/save scenario. The problem we are discussing is that the domain model is needed in some form before the parameter can be repopulated from the form save. The technique you are using is to reread the data from the database before the parameters are set. An alternative technique would be to put the domain model into a place in the session--so on the save, you can retrieve the the model from the session and then allow the parameters interceptor to populate the new data. (This is referred to as detached objects in the Hibernate world) The advantage of putting the model in the session is that if some else modifies the data before you reread the data, but after you have displayed the edit page, you will not have the original model. This particularly a problem with a model where you are dealing with lists of domain objects. In this case, the edit will fail because you will be trying to set parameters on items that might not exist anymore. (Or you've pulled in data that the user doesn't know about) Therefore the safer technique is to save off the model. If you're concerned about putting too much into the session, you can store the data in a cache, such as ehcache, that will store items to disk if there are too many things in memory. (This is the technique that we used--we called it a model repository and we created a couple different implementations) I would love to see something like this out-of-the-box with struts2, but nothing currently exists.
Thanks, I really appreciate your suggestions. However, I prefer a stateless approach because (I think) it helps to keep things simple in this case. Using some kind of cache between page requests is more like a stateful approach that I would like to avoid here for simplicity reasons. Well, having Struts passing parameters in the order defined by the html form would solve my problem. :-) Regards, Célio. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
