JSF Nonsenses: May 2009

Tuesday, May 12, 2009

JavaScript and Facelets

Did you know that you're not allowed to use the full syntax of JavaScript language with Facelets? Well, I didn't and it took me over 4 hours to find that out. Let me explain:

Here's a simple JS function that will cause the rendering engine swallow it's own tongue and spit a nasty error message:


  <script>
function doSomething(items) {
  if(items.length > 0 && items.length < 5)
    return;
}
  </script>

First of all the < and > are not valid characters in XML so they are not valid in Facelets as well. And if you substitute them by < it will be rendered as < which makes the usage of < character impossible.
The same situation is with > sign as well as with && operator.

Of course you might say that my doSomething function makes no sense - it's for educational purposes only!

May the spirits protect us from Facelets!

Using Maven's Apache MyFaces archetype with GlassFish v3

I've faced a simple task to create a component that will render a recursive unordered list that can be later on turned into an accordion. Nothing really fancy.

Since there's no such component that I know of to do the rendering in the way I want it to I've decided to create my own component.

Using Maven I've created a new project from MyFaces archetype available in the default Maven repository. Armed with an example application I started my work.

The shock came right after running the generated app for the first time. Here's a snippet of the jsp page:


<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f"%>
<html>
    <head>
        <title>Hello World</title>
    </head>
    <body>
        <f:view>
            <h:form id="mainForm">
                <h:panelGrid columns="2">
                    <h:outputLabel for="name" 
                      value="Please enter your name" />
                    <h:inputText id="name" 
                      value="#{helloWorld.name}" 
                      required="true"/>
                    <h:commandButton value="Press me" 
                      action="#{helloWorld.send}"/>
                    <h:messages showDetail="true" 
                      showSummary="false"/>
                </h:panelGrid>
            </h:form>
        </f:view>
    </body>
</html>

Using NetBeans (the only freely available IDE that makes sense for Java development) I've started GlassFish v3 and deployed my newly generated application to the server.
The "Run" option on project has opened Firefox with the right address and everything looked OK. So I thought: let's take a look at the generated Html before I start adding something to it. And that was the moment when the fun begun!

The generated HTML has the following structure:

1. Form (as a top-level element) with all the controls
2. Html with Head and Body containing some JavaScript code and nothing more.

Can someone explain to me the reason it is so difficult to produce some proper output even from the simplest application??? Is this something you'd put your money into (I mean like more than one dollar of course)?

Monday, May 11, 2009

...because it's designer friendly

Here's just one quick note that I just couldn't live without sharing.

There's an opinion that it is better to use a more declarative approach to web development (like JSF/Facelets does) because it is easier and more comfortable for the web designers to interact with the page design.

Web Designers are NOT developers! Much less JavaEE developers knowledgeable in JSF technologies. Get over it! NetBeans, Eclipse - those are Developer tools - not designers'! A designer prefers Photoshop for graphics (oh wait - there's no such thing in Eclipse, NetBeans nor in Idea like advanced image editor) and Expression Web or Dreamweaver (again, no viable counterpart in any of the IDEs).

And now for the most shocking part:

Designers don't speak JSF/Facelets nor any of the JSF frameworks like RichFaces or IceFaces. They speak HTML, CSS, possibly JavaScript too (if you're lucky!). For them a div is a div, a span is a span and a a-href is an a-href.

And I distinctly remember someone saying that it is easier to get designers to contribute to the project if you use Java Server Faces...

Ghosts in the browser

It's not a bug - it's a feature

Did you know that you're not where you are? I mean virtually of course. Confused? Read on...

Let's have a simple example: 2 simple views (or pages or however you'd like to call them). One that asks for your name and the other one that says that you're the master and this kind of things. A simple "Hello, world!" application. Nothing fancy.

Now let's assume the obvious which is: you're writing it using Java Server Faces. It's good for everything so why shouldn't it be good for a Hello, world! application?

So we have it, one edit (h:inputText, for whatever reason) and a button (h:commandButton, again like it couldn't be simply a button... nevermind) and we have the next page that shows your name with a nice greeting (using h:outputText for whatever reason, like text nodes were smelly or something... nevermind). Of course we have all the necessary bits and pieces there: a bean with sayHello method, navigation cases set up properly, all the entries in web.xml are there - we're good to go!

Now let's run our glorious application.

1. We're at the start page that kindly asks us to enter our name into the box. Well, we're not that open to mind control so we enter something like "Harry Potter" and click the fancy button that's on the same page.
2. Now we're on another page, this time it's the page saying, that "Harry Potter is most welcome" and "that you can click the back link to get back".

But wait! Have you noticed the address bar? Whatta heck?! It is still pointing to the page where we've had the opportunity to enter our name. We think "something is seriously wrong with our application". But in fact it's not our application that's wrong - it's just how JSF works.

It's not a bug - it's a feature :D And you can't do anything with it. Get over it! Don't look at the address bar - there's nothing of interest to you.

Comments are not comments unless they are comments

The concept of comments is clear to everyone, so it would seem. We developers use them all the time to comment-out code that we'd like to skip temporarily, to better document our intentions. Comments are just plain old descriptions, inactive elements in the code. So it would seem...

Apparently the creators of Facelets didn't think that this is the case. Once you comment out a piece of code (again, for whatever reason) it does not mean it is actually not running!

Some one brave enough decided that the default behavior of comments should be the one of the ordinary template, meaning all the elements that are active (so to speak) are still running! All the references to beans, all the references to resource bundles and what have you are still being used to produce a nice comment!!!

There's of course an option to turn this insane behavior off (facelets.SKIP_COMMENTS) but the default behavior might give you a nice head spin.

jQuery in RichFaces

It's a glorious day! jQuery (my absolutely favorite JavaScript framework) is part of RichFaces! I just found that out.

Well, my happiness didn't last very long. As soon as I realized that it's backed into richfaces-impl jar and that it's an ancient version my lucky day become a nightmare.

RichFaces just have to play nice with everyone, they just can't live without everyone on board. So we have Prototype (a very good library btw) that makes heavy use of the $ sign, then we have jQuery (same thing) and Scriptaculous (obviously).
Did any of the designers of RichFaces ever thought that I might personally dislike the mess they are introducing with this many libraries?

And btw - the ancient jQuery is still ok - but the nice $("#output").dosomething() syntax is gone since jQuery is the one that has to play nice with the rest. That is just not fair! Imagine fixing every single plugin you're trying to use with jQuery to use the full name instead of the dollar sign. Imagine upgrading a set of such plugins... Cool, ain't it?

I've heard that in the latest beta version of RichFaces they have upgraded jQuery to 1.3.2. Let's see if they'll be able to keep up with the latest release once they go GA.

Ajax - the proper way

Here's the problem: I need to call a method that will return some JSON that will be evaluated by the client and according to the result of this operation some action must be taken. All should take place in the browser and the server should return only a JSON response with the data I need. Nothing more.

Let's see - nope! No can do, man! Because you have the feature A, B, C,... Z it's not possible! You have to keep the view state (WTH?) up to date! You need the view state on the other end (what for?).

Here's how it's done in almost any framework out there that makes use of the MVC pattern:

1. Create a method or a class and a method (depending on the technology) that will contain the actual server-side code.
2. Find out the address (usually it's as simple as /controller/method called an action in this case)
3. Use jQuery to make the call and do the rest of the processing.

Can anyone tell me why it is so hard to do in JSF?

Welcome JSF users!

Welcome to this new place in virtual space where you can express your darkest feelings about the sole nature of JSF (Java Server Faces) and other technologies that are connected to it (Facelets, JSF libraries and the like).

This blog has arose from the need to express my personal dislike for that glorious set of utilities that have made my life a misery.

Feel free to stop by from time to time to share your thoughts (be it good or bad) or even lecture me to prove how wrong I am. All comments are welcome.

May the force be with you!

Blog Archive

Tuesday, May 12, 2009

Monday, May 11, 2009