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.
Related
Just like TImageList contains a collection of images, is there a similar component for generic files?
I know I can embed files as resources, but I'd like the convenience of storing different groups of files in different "TFileList" components, and to be able to retrieve files by name or by their position in the list.
Extra points if such a component allowed some sort of design time preview of the file content (just like TImageList lets you see what each image looks like, at design time).
(I come from Delphi where I wrote my own component to do the above, but before I rewrite and port the property editor and all that to Lazarus, maybe there is already something that is tried and tested...)
Thanks!
You can use pre-defined lazarus TFPGList to specialize list of the type, that you want, for example - UTF8String
But, there's no T<>List as a component, only as object.
So, yes, this feature will be useful and i can implement, if have time,
also, there's a very limited RTTI, which has been updated only a few months ago, so you can access Methods and Properties now, so FP is more systemized, than delphi pascal, but also not so enterprise-developed, which limits it to implementations for common opensource and shareware project problems.
Nevertheless, it is more stable and supported, even my friends can contribute.
For our Xpages application stack we have to create cca. 100 controls that will cover our new UI parts/helpers and some additional services. These controls are meant to be very general and have to be used by many Xpages applications. Now question is how to share these controls among applications(databases). Controls need some managed beans to work, also some CSS, JS and images. To copy the whole stuff into each application and maintain it somehow is not the way (even design inheritance doesnt help here). What's more ... mixing these 100 controls among application specific controls is real hell as controls doesn't support any namespaces or some packages grouping (like java in Package Explorer), so at the end we have very long list of controls in DDE which is nightmare to navigate and work with.
We tried to use Extension Library approach and followed this tutorial
http://www-10.lotus.com/ldd/ddwiki.nsf/dx/Master_Table_of_Contents_for_XPages_Extensibility_APIs_Developer_Guide
... but honestly I tried 3 times on my computer from scratch and even example project from tutorial didn't work properly and still caused some errors in update site project. My colleague also tried this on his computer with no luck. And entire process as described in the article above is set of many java classes, XML and configuration files even for small control (eclipse plugin project -> feature project -> updated site project and then you have to install this update site test it and when bug occurs you have to run another cycle ...). Comparing to e.g. this http://tapestry.apache.org/component-classes.html its extremely heavy weight approach in Xpages.
So my question is, is there any other approach that can help us in this area to share controls among applications? Or is there any update expected in this area for upcoming Notes release e.g. R9.1 ?
the most efficient way to share controls is an extension library. It does come with a learning curve. You could use Nathan's XSP Starter Kit to ease your pain. Alternatively you can use the import/export plug-in from OpenNTF to move controls (and their supporting files) around.
In any case: XPages custom controls do support name spaces and grouping -> just have a look at the property panel of a control. You can define:
the namespace (defaults to xc, but you are free to design your own)
the group it should appear in
icons
how it looks at design time (to hide the inner workings)
So step 1 is to group and clean and then think about the distribution. Extlib definitely would be best.
There is good ol' method for sharing design elements in NSF: templates. You can make your database a template, and then inherit just specific design elements by copy/pasting them at designer level. In design element's properties view, Design tab, look for "Inherit from the design template" property. It contains template name from which you copied the element. Watch out for the property "Prohibit design refresh or replace to modify", it should be off.
This has some consequences when deploying the application to production, though, so please, read the documentation/help about template inheritance. Especially combination with XPages/custom controls requires the template to be built and signed.
We use it to share custom controls like application layout and picklists with no problems.
I'm trying to figure out if it is possible to use ServiceStack Razor for old-fashioned server-side form validation.
By way of example: a GET to a url returns a razor template with a form. When the user POSTs the form, request DTO is validated and if there were errors, the user is shown the same form, with original values re-populated as and fields in error marked somehow. If, on the other hand the request DTO is valid, the service will redirect the user to another page.
Is that scenario possible?
If so, how would one go about implementing it? I presume I'll have to write certain filters or features for this to work, however I'm wondering what strategy will require minimum amount of coding.
(I understand javascript validation is possible, however my question is specifically whether it is possible to round-trip the form with server-side validation).
Take a look at ss-validation.js, it can be used to apply validation errors to your form based on ServiceStack's ResponseStatus.
So we write all our validation code server side using FluentValidation, then on round trip ss-validation reads ResponseStatus and applies markup.
Out of the box is assumes Bootstrap style validation, but it's fairly easy to modify to suit your needs, e.g. we amended to display inline icon tool tips instead of inline/block messages, and provide an error summary.
After a lot of spelunking of the ServiceStack codebase, it seems it is theoretically possible to achieve the desired scenario.
The code already contains ModelMetadata and ModelMetadataProviders classes, and some of the HTML helpers are ported from System.Web.Mvc.
Sadly, the classes are not fully wired, so I guess it will require solid amount of work to get everything working correctly as one would expect.
Hope you are doing fine.
This is my scenario.
I have multiple (20+) Liferay portlets that use grids/tables to display data.
Each portlet retrieves data based on a different criteria.
However, the grid is the same with some common functionalities such as filtering, pagination, data export etc.
Currently, each time we have to make a change in the grid style, I have to make the change in each of the 20+ portlets.
This is really inefficient and results in a lot of time wasted.
Hence, I was wondering whether it is possible to create a generic 'portlet' or 'composite' so that it can display data from multiple portlets?
To elaborate, the generic portlet/composite will contain the grid, filtering, pagination, export etc. features.
This generic portlet/composite will receive data from the various portlets and simply display it.
Hence, if I need to make any change in the grid style, making the change in only one place will suffice.
Has any one experienced such a scenario before?
Do you have any solution?
Thanks in advance for any help.
If you need only retrieve data by different criteria, have functionality like export data,print,pagination etc, you don't need 20+ different portlets you may use one portlet and have 20+ it instances, each would be configured like enable.export, enable.print, data.criteria and so on. Inside portlet your logic would build grid and data what you need.
If you really need Generic Portlet you may try to have all your 20+portlets in one .war. You'd simply include jsp's that are common within some portlets, extend controllers etc.
Even more... If you need to send data between portlets you may create javascript controllers that will send events each other, through Ajax get data and fill in your jsps(in that case you may use some templates). Please ask if something is unclear.
The best solution would be to use one portlet for retrieving all data, and generalise the data retrieving with one interface and different implementations - not with different port lets.
You can though try to use Liferay's Interportlet Communication facility to provide data from source portlets to target portlet - http://www.liferay.com/community/wiki/-/wiki/Main/Inter-portlet+communication
But it has it's own caveats - you'd either have to submit data in browser using AJAX or JS events, or have to use JSR-286 (Portlets 2.0) events that work on server-side, but require one to trigger an action in order to make events occur (i.e. open portlet with action URL and not render URL). More on it here - http://www.liferay.com/community/wiki/-/wiki/Main/Portlet+to+Portlet+Communication
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.