I have been doing Tapestry 5 work for about a year now, and I’m definitely still learning, but I think I know my way around fairly well. I really (mostly) like it, and I think it is way easier to use than Tapestry 4, as well as many other frameworks. It also results in a nice clean code base which isn’t too difficult to approach. There are, however, a couple of areas that I really just find confusing. Some of them aren’t too bad once you get to know them, but they are hard to learn. I think it is important for most aspects of the framework to be easy to learn/use, because if people encounter pain during their initial impression stage, they will abandon the framework and use something else.
The first issue I have is with the way that the Select component works when you want to have a dynamic model for the list. I think this is a common requirement for applications, so it is something people will most likely encounter fairly quickly. For complex models, it is usually necessary to implement two interfaces: SelectModel and ValueEncoder. The interfaces make sense once you get to know them, but I think the learning curve is quite steep for such a common task. I’m not sure how this could be solved, but it seems like Tapestry 4 may have had a more simple system (though I’m sure it had some problems which led to it being redone).
The second issue I have is with page context. Often times in standalone web applications, I have created pages which take query string parameters. These can be referenced by external apps or pages, and used to link between pages of an app. Tapestry’s equivalent is the page context, which can be used to pass contextual data between pages. There are two problems that I’ve encountered with page context. First, it is limited in what data it can represent. It is generally just a list of nameless parameters. This makes it difficult to pass only certain parameters or parameters with names. Second, the format for the URL is not a part of the spec (correct me if I’m wrong), so it can only reliably be used via other Tapestry pages. This makes it difficult to pass data in to a Tapestry page from an external place.
So to sum it up, I’d like to reiterate that I really do like Tapestry 5 and hope for its widespread adoption, but it has a few points that are difficult to deal with. If these issues were addressed in a future version, I think it would help ease a new developer’s adoption of the framework.