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The following page has been changed by JasonCarreira: http://wiki.apache.org/struts/RoughSpots ------------------------------------------------------------------------------ * [jcarreira] We've implemented this at work with WebWork fileupload + DWR + a class that looks at the file as it's uploading to see how big it is on disk * [frankz] Just an opinion, but this seems to me too specific a use case for a framework to encapsulate. I think having an example showing how to do it, perhaps what jcarreira has done at work, would be great, but I for one wouldn't like the framework offering this out of the box... I think it is possible for a framework to be able to do TOO much! * [tm_jee] I think this is pretty use case specific as well, but a progress monitor ui component would be nice. + * [jcarreira] If we agree that supporting file uploads out of the box is important, then this is just a nice feature for that support to let the user know how much of the file has been uploaded, etc. 1. Better error checking for UI tags. The freemarker error message, while great for freemarker users, look like gibberish. People should not be forced to learn freemarker. So in such cases, the tags themselves should check the parameters and report back sane messages, even if that check is duplicated in the templates @@ -280, +281 @@ 1. Specify and simplify Interceptor scope. Currently, you have an Interceptor that calls actionInvocation.invoke() and then returns a different result than actionInvocation.invoke() returns, the actionInvocation.invoke() result will be used anyway. This is confusing and muddies the meaning of the Interceptor API, which IMHO should simply wrap the action not the action all the way through to the end of the result. The reason it's set up the way it is, as I understand it, is so that Interceptors can clean up resources like connections after the result is returned. However, I wonder if we can implement a request based object that can take care of such resources and destroy them at the end of the request rather than using Interceptors in this way. * [crazybob] That was really surprising and confusing to me at first, too. I thought it would have been more intuitive for the result to run after all the interceptors returned. I'm not sure whether we should change it or not. I like the idea of interceptors being able to clean up after results a lot more than I like the idea of an interceptor being able to return a different result. * [Gabe] It is an advantage for Interceptors to be able to clean up at the end of a request, but it isn't great how they do that either. Take for example an action chain. If you have a create connection Interceptor surrounding each of the chained actions, you will open two connections, which besides being wasteful could cause problems with other resource types. I wonder if we can create some sort of request scoped ResourceManager class that can allow Interceptors to create resources or access them if they exist and specify how they should be destroyed at the end of the request. Thus in the connection case, the Interceptor could check if the resource manager had one and if not create it and add it to the resource manager for other objects to use. (Another option of course is an inversion of control approach) + * [jcarreira] Interceptors can still change the result... Implement PreResultListener and in your callback, change the resultCode and voila! The result executed will be changed. The PreResultListener interface lets you register your interceptor to get a callback after the action and before the result is executed. Oh, and on the ConnectionInterceptor -> It's just like AOP. You have to check if it's been done already and know not to create a new one or close it on the way out. I do this all the time in AOP interceptors, so why should this be different? Personally, I'd rather use the same connection across all of the actions in a chain than clean it up after each one and use a new one per action. For request scoped resources, take a look at Spring's scoped components. I'm using them at work and they work pretty well (a few issues I'm working through with them notwithstanding). == Tim's Issues == I'm new around here, so be nice ;) I probably have a lot less WW experience than most, so I apologize in advance if I'm flat out wrong about some of the things here. @@ -288, +290 @@ * [crazybob] I prefer an injection-based approach. You can use the `ScopeInterceptor` to pull an object off the session and pass it to your action. Or you can use Spring to inject session-scoped objects into your action (though I would avoid Spring personally). + * [jcarreira] I can attest that the Spring scoped components work well with WebWork. It's what we use at work for maintaining session or request state. + 1. In tandem with the previous point, since Actions are already stateful, it'd be nice to have the ActionContext injected into the Action. One benefit is when a newbie developer needs it, the linkage is obvious (they don't have to a priori know about the ActionContext, they're being handed in it on a platter). If the developer can subclass ActionContext, it would also encourage them to implement a base action which accepts the context inject and leveraging the fact that JDK 1.5 allows co-variant returns, also write a getContext() method that returns the down-casted type; they wouldn't have to do ((MyActionContext) ActionContext.getContext()).getUser() for example, just getContext().getUser(). * [frankz] This might well address the issue of !ActionContext being !ThreadLocal. If it was injected, it wouldn't need to be !ThreadLocal to get the same basic effect, and maybe more importantly, it wouldn't automatically be available to helper classes as it is as a !ThreadLocal. That would address my concern about "inappropriate" usage of !ActionContext. + * [jcarreira] I think this is a bad idea, in general. Actions should specify the exact things they need and have them supplied, not just ask for the "world" (the ActionContext is the world the action lives in). 1. HTML analog tags should stick to HTML attributes. I dont' mean they shouldn't have more functionality, but the attributes should be identical where possible, and they shouldn't do things like render a label and an input. Keeping them more like regular HTML tags makes them easier to ramp up on, and more non-developer friendly * [MJ] I see the following options when it comes to tags. (1) Use plain HTML + implicit scoped variables like "actionName", "actionAddress", etc. to create dynamic values; this looks pretty compact with JSP 2.0. (2) Use 1:1 relation between WW tags and HTML tags. (3) Use 1:M relation between WW tags and HTML tags, like to create data entry form or a table. (4) Use non-HTML-looking tags + more abstract attributes + "media" attribute, thus creating something like JSF renderer for different media. Choosing between (1) and (2) I prefer the first one. + * I'd encourage people to give the ww: tags a spin... they're really much more powerful than the JSTL or previous struts tags and you don't need so many tags to do things. On being closer to HTML attributes, do you have some examples? + 1. Actions should return concrete objects, not symbolic results. Symbolic results might have been optimal when you had one event/method per action and the outcomes were always whole-page views, but they get in the way now. When you want to return anything that requires more than the symbol, you have to do some less than intuitive things to make the Action and the Result cooperate. I'd prefer to see a concrete Result get returned from Action methods, which would allows developers to do more powerful things more easily. There are a bunch of ways to make it backward compatible too. You could return 'new SymbolicResult("success")' and have the SymbolicResult do the lookup stuff (You could even redefine the String constants to be SymbolicResults). You could alternatively use a static class to do Results.find(SUCCESS). Or you could even allow method to continue to return String or Result, and if String wrap it in a SymbolicResult. * [frankz] +1. This is one area where I personally think Struts had it right and we've seen frameworks getting it "wrong" subsequently. !ActionForward I believe is the right concept, even if the realization might not be optimal. I think the difference between return "ok"; and return new ActionResult("ok"); is pretty minimal, but the later opens up a lot of possibilities being a true object that can have behaviors and properties and such. * [crazybob] There's no reason we can't support both `String` and `Result` return types for action methods. I think we should encourage `String` though. Can you provide some example use cases for when `String` isn't enough? @@ -300, +307 @@ * [crazybob] I'm not sold on this. 1) The result pulls values from the value stack, not the request attributes. 2) I ran into a case recently where I ''thought'' I wanted to return a real object at first: I wanted the action to dynamically select a redirect URL. I ended up doing this: {{{ <result name="..." type="redirect">${url}</result> }}} 3) Enabling users to return either a real object or a string is going to impact the interceptor API, too. :( 4) Wait a second... you can do what you want right now! Create a new result type which looks up a `Result` object on the value stack and delegates to it. Then map a global result to the new type. For example, you could return `CUSTOM`, and the the result type would execute the `Result` returned from `getCustomResult()` on your action. ;) + * [jcarreira] -1 I've never, ever seen anything that needed this, and it makes the API requirements on the action classes more tightly coupled. Result configurations and Result instances can pull values from the value stack (including but not limited to action properties) so you can easily set up any of the values you want to give the result as properties of your action and have them pulled. == Nice to haves == --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
