I use JSF 2.1.7 Mojarra with Facelets, and most of my pages are crud pages, backed with view-scoped managed beans, using post to the same page (return ""). Depending on flags I have in the bean, I render the html code I want (list of results, forms for insert/edit/delete) into the crud page.
In terms of good practice, good design, good working of any webapp, etc... is it better to use PRG pattern? Are there any serious problems if PRG is not used?
In my case, I'm thinking of using PRG, but I think it's quite tedious, as f:viewparams have to be used for any form field, and it's a hard (tedious) job to change all the pages. Am I wrong? Which changes do I have to do convert POST to GET in JSF?
The reason I'm thinking of use PRG (apart for the bad user experience showing alert popups) is a problem I have posting a form when the session has already timedout.
Thank you.
Does anyone have a link to a concise summary of what makes a portlet "JSR-286 compliant" vs being only "JSR-168 compliant". I've got a copy of the spec and that's anything but concise so linking the spec is not a useful answer. I've searched the web for an hour now and I've found nothing that is clear (aside from the spec, which of course requires that you read the previous spec too, and then weed out the "new features" from the "required compliance".
Particularly I've found that there's quite a bit of confusion out there on the necessity of web.xml, which appears to come from people using Liferay and not realizing that Liferay is dropping in a web.xml for them.
Do JSR-286 portlets require a web.xml file in their WAR files?
What I'd really like is something that contains one or more of the following lists:
Things you have to do to a JSR-168 to make it become JSR-286 compliant
Things you must not do, that would cause an otherwise JSR-286 compliant portlet to be considered only JSR-168.
You can leave "use the portlet-app_2_0.xsd" off the list, as I consider that part obvious.
I'm open to the answer that both lists are empty aside from the DTD/xsd for portlet.xml, and the difference is only in what the portal supports, but please back that assertion up with a link or other reference.
The reason I care is I see posts about Vaadin portlets in Liferay that imply that some features are not available for JSR-168 portlets... It may also be that some logic in Liferay switches based on which version of portlet.xml it sees, but I haven't confirmed that either so that would be interesting information too, but not the answer to my question.
According to this doc, but it's also mentioned in jsr286:
The JSR 286 spec(Portlet 2.0) does not break binary compatibility with JSR168(Portlet 1.0). This means that all portlets written against the Portlet 1.0 specification can run unchanged. The only exceptions to this rule are:
renderResponse.setContentType is no longer required before calling getWriter or getOutputstream. In JSR168, calling getWriter or getOutputstream without previously setting the content type resulted in an IllegalStateException.
getProtocol for included servlets / JSPs returns ‘HTTP/1.1’, In JSR168, it returned null.
So as long as your jsr168 portlet doesn't depend on the value returned by getProtocol() you're safe (ie every jsr168 portlet is a jsr286 portlet).
The posts you see seem to be logical as jsr286 is a newer spec and there are some features that make jsr268 portlet not a jsr168 portlet.
Ok, Since I've not found anything new that distinguishes a 2.0 portlet from a 1.0 portlet (aside from using additional services and ) I'll begin the lists for my answer here.
Must Do:
Conform to the 2.0 XSD for portlet.xml (xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd")
Must Not Do:
Rely on getWriter throwing an exception if renderResponse.setContentType has not been called yet. (Seems unlikely anyway)
Rely on getProtocol() returning null
The upshot is, if you simply convert your portlet.xml, you are now "286 compliant" unless you relied on the two items in the second list for your program flow. I can't find anything else, but if someone finds another item for these lists, please edit.
I don't often have need for tomahawk components anymore since jsf 2.0 provides great selectOneMenu support and most of other functionality I used to use them for, but when it comes to a selectOneRadio component I don't know of another provider with a layout="spread" option. This is essential from time to time to achieve a certain layout I'm asked for.
I'm using Tomahawk for exactly this purpose but recently discovered some serialization issues caused by this component during failover. I was wondering if anyone has discovered another provider with similar "spread" functionality or if anyone has written/published an alternative based on h:selectOneRadio?
We also wanted to use the "spread" option - in our case for DDA compatibility (no using tables for layout) but for political reasons were unable to use Tomahawk. We ended up writing our own custom renderer for radio buttons and checkboxes.
It wasn't too hard, took me a few hours to get it working the way we wanted. I'm at home for a couple of days without access to the code base so I can't give you the exact code but it's a pretty simple matter of overriding the encodeBegin() and decodeBegin() (or encodeEnd() and decodeEnd() depending on your usecase) methods and writing the html appropriate for your application.
I'm currently learning about JSF 2.0 and i would like to ask about how to do UI validations in a good way.
I notice that in JSF 2, validation has predefined tags so that it could be used across manya JSF pages, and we can even build our own validators.
But one thing that concerns me is that when i develop around hundreds of JSF pages, and many of the validations are the same, and it is hard to manage this centrally.
For example, for my currency input which has id of "PaymentAmount", is heavily used in many JSF pages. It has it's own unique validation rules, which define the fraction digits, min and max, etc. If im to use the validator tags in the JSF pages, there will be many copy paste involved. And if im to change the rules of this "PaymentAmount", i'll have to change in many JSF pages.
I would like to have the validations offered by the JSF like the date validation, required, range, etc, but without all the duplicates across JSF pages.
Is there any ideas to cope with this problem ?
Use the Bean Validation API introduced w/ Java EE 6:
http://download.oracle.com/javaee/6/tutorial/doc/gircz.html
Define all you validation centrally in your POJOs, and re-use throughout your application.
Background
I'm going to develop a new web-application with java. It's not very big or very complex and I have enough time until it'll "officially" start.
I have some JSF/Facelets development background (about half a year). And I also have some expirience with JSP+JSTL.
In self-educational purpose (and also in order to find the best solution) I want to prototype the new project with one of action-based frameworks. Actually, I will choose between Spring MVC and Stripes.
Problem
In order to get correct impression about action-based frameworks (in comparison with JSF) I want to be sure that I use them correctly (in a bigger or a lesser extent).
So, here I list some most-frequent tasks (at least for me) and describe how I solve them with JSF. I want to know how they should be solved with action-based framework (or separately with Spring MVC and Stripes if there is any difference for concrete task).
Rendering content: I can apply ready-to-use component from standard jsf libraries (core and html) or from 3rd-party libs (like RichFaces). I can combine simple components and I can easily create my own components which are based on standard components.
Rendering data (primitive or reference types) in the correct format: Each component allow to specify a converter for transforming data in both ways (to render and to send to the server). Converter is, as usual, a simple class with 2 small methods.
Site navigation: I specify a set of navigation-cases in faces-config.xml. Then I specify action-attribute of a link (or a button) which should match one or more of navigation cases. The best match is choosen by JSF.
Implementing flow (multiform wizards for example): I'm using JSF 1.2 so I use Apache Orchestra for the flow (conversation) scope.
Form processing: I have a pretty standard java-bean (backing bean in JSF terms) with some scope. I 'map' form fields on this bean properties. If everything goes well (no exceptions and validation is passed) then all these properties are set with values from the form fields. Then I can call one method (specified in button's action attribute) to execute some logic and return string which should much one of my navigation cases to go to the next screen.
Forms validation: I can create custom validator (or choose from existing) and add it to almost each component. 3rd-party libraries have sets of custom ajax-validators. Standard validators work only after page is submitted. Actually, I don't like how validation in JSF works. Too much magic there. Many standard components (or maybe all of them) have predefined validation and it's impossible to disable it (Maybe not always, but I met many problems with it).
Ajax support: many 3rd-party libraries (MyFaces, IceFaces, OpenFaces, AnotherPrefixFaces...) have strong ajax support and it works pretty well. Until you meet a problem. Too much magic there as well. It's very difficult to make it work if it doesn't work but you've done right as it's described in the manual.
User-friendly URLs: people say that there are some libraries for that exist. And it can be done with filters as well. But I've never tried. It seems too complex for the first look.
Thanks in advance for explaning how these items (or some of them) can be done with action-based framework.
I'll do my best to answer regarding Stripes. I've used Struts and JSF in the past, but not recently, so at best I have vague notions and feelings about them.
We are intimately familiar w/ Stripes, use it for most everything now, and really enjoy it. It is easy to jump into, supports many of the complicated scenarios, but you are also free to work OUTSIDE of it, which is really important when you want to build your own ajax widgets or talk to another system or something.
If you go the stripes route, I definitely recommend buying or download the book. It is a one stop shop for everything you need for Stripes, and is practically the only documentation for Stripersist (really nice feature, but NO web docs).
Rendering content: I can apply ready-to-use component from standard jsf libraries (core and html) or from 3rd-party libs (like RichFaces). I can combine simple components and I can easily create my own components which are based on standard components.
This is similar. Core, Html, Fmt, etc. as well as any custom tags you find, inc. display:tag, pack tag, and create your own. However, obviously you do not deal at the component level now, you deal with a tag that determines what is on the page / sent to or from the server.
Rendering data (primitive or reference types) in the correct format: Each component allow to specify a converter for transforming data in both ways (to render and to send to the server). Converter is, as usual, a simple class with 2 small methods.
Stripes has many built in converters, and it is easy to create custom converters for your more complex data types. Stripes supports very complex data structures to be mapped with little hassle. Combined with Stripersist, for example, I can put my model object directly on the ActionBean, put a few of the fields on the form, and Stripersist will hydrate the model from the db (based on its PK) and update that with the fields I put on the form - all before releasing control to me on the ActionBean.
Site navigation: I specify a set of navigation-cases in faces-config.xml. Then I specify action-attribute of a link (or a button) which should match one or more of navigation cases. The best match is choosen by JSF.
Navigation in stripes is based on what you name the ActionBeans, initially. There is no xml. Additionally, pretty urls are an annotation at the ActionBean level in Stripes 1.5, so you can do things like #UrlBinding("/{$event}/{model}") where /view/5 would take you to the "view" event handler for your Model object with the ID/PK of 5.
Implementing flow (multiform wizards for example): I'm using JSF 1.2 so I use Apache Orchestra for the flow (conversation) scope.
While I only am vaguely familiar with the concept of conversation scope, Stripes has Wizard Form functionality, but I haven't used it and am unable to really expand on that. I think it is a similar idea though.
Form processing: I have a pretty standard java-bean (backing bean in JSF terms) with some scope. I 'map' form fields on this bean properties. If everything goes well (no exceptions and validation is passed) then all these properties are set with values from the form fields. Then I can call one method (specified in button's action attribute) to execute some logic and return string which should much one of my navigation cases to go to the next screen.
Not drastically different. Instead of components on your [action] bean, you now have Java or custom types. ActionBeans are created per request and thrown away, unless you do something like put it in session, or wizard, or whatever. This is nice, because all the instance variables get mapped to the data from the form, you use it, then throw it away, and don't have to deal with any synchronization issues like struts did. After you do your thing with the data, Stripes lets you send a ForwardResolution (OK status), Redirect, or Streaming (JSON, file, etc). The Redirect-after-POST pattern is implemented nicely with the idea of flash scope (3/4 down the page).
Forms validation: I can create custom validator (or choose from existing) and add it to almost each component. 3rd-party libraries have sets of custom ajax-validators. Standard validators work only after page is submitted. Actually, I don't like how validation in JSF works. Too much magic there. Many standard components (or maybe all of them) have predefined validation and it's impossible to disable it (Maybe not always, but I met many problems with it).
Stripes allows validation in annotations on the instance variables on the ActionBean. They allow some defaults, required, maxlength, etc. or you can always create your own. The default is easy to add and flexible, while there is always the ability to make something completely customized.
Ajax support: many 3rd-party libraries (MyFaces, IceFaces, OpenFaces, AnotherPrefixFaces...) have strong ajax support and it works pretty well. Until you meet a problem. Too much magic there as well. It's very difficult to make it work if it doesn't work but you've done right as it's described in the manual.
This was my big problem with the JSF way of doing things. Even if you did get the widget right, you're still stuck with THAT widget. With Stripes, you can use whatever latest and greatest Jquery has to offer, and as long as you send the right GET or POST to the server, stripes knows what to do with it and can easily send JSON back. I think component frameworks fit a niche a few years ago much better when AJAX was hard, but JQ makes it so easy now.
User-friendly URLs: people say that there are some libraries for that exist. And it can be done with filters as well. But I've never tried. It seems too complex for the first look.
#UrlBinding, it's as easy as that.
My answer is not the one you want to hear: Don't switch from Component Framework to action framework
I switched the other way around after many years of action framework development and I'm never going back.
Of the 8 use cases you mentioned, only one comes to mind where Action frameworks are obviously better, and that is URL design / friendly URLs. It can be done in component frameworks as well, but much easier in Action Frameworks (especially in Stripes where you just annotate your ActionBean with the url).
I would advise you to try wicket, it is very easy to learn (much easier than JSF) and it let's you re-use many existing components as well.