I'm new to JSF and developing web applications with Java.
I'm basically developing a pretty complex interface, with lots of AJAX content loaded (Pagination, posts, comments, ...).
I'll start with a basic example, a user writes a comment. The form is sent through JSF f:ajax to the server and then I can do a render="sectionId", but the problem is, that I want to make the post not just appear, but slide down and even toggle background color.
How can I obtain this sort of effect using JSF and Javascript?
The designer (who knows only HTML/CSS/Javscript/Jquery) says that usually, he just does a Jquery AJAX call to a page with a string of data and then the page generates a JSON encode that he can then use to do all the magic.
I'm not asking how you do the toggle/color in jquery, it's the communication between the JSF and Javascript. So how can I send to his javascript the newly generated HTML code, so that he can what he wants with it.
Thanks for any help.
JSF is a server-side technology and you'd typically conditionally display content within
a construct such as a panelGroup, so why not include your jquery magic inside a ready
handler inside the conditionally rendered panelGroup like this:
<h:panelGroup id="ajaxRenderTarget">
<ui:repeat value="#{bean.listOfComments}" var="var">
... display required information ...
</ui:repeat>
<h:panelGroup rendered="#{bean.showJqueryEffects}">
<script type="text/javascript">
jQuery(function($) {
... funky effects here ...
});
</script>
</h:panelGroup>
</h:panelGroup>
Where I've used ui:repeat in the above example you could be and probably would be using any data iteration component from jsf or a component library such as a datatable.
Another thing to consider is OmniFaces which has <o:onloadScript> and a host of other tags which are worth knowing about.
One mistake to avoid is trying to load JSF pages using jQuery ajax functions, the server will have no state of the component tree and it won't work.
Related
I am using sitemesh for a spring based site. The problem is that I have some javascript that I want it to run on the onload event of only one specific page using jquery $(function() { ... }) and not on every page.
I have included the jquery.js in the bottom of my decorator, after the body. So, if I try to include a <script> tag in the body of my decorated page the script won't be executed because jquery will be loaded after that! I know that I could include the jquery.js in the header of my decorator so it will be before the custom script in the decorated page however I don't really like that solution since it will contain javascritp in the head of my page.
So I would like to have something like a placeholder in my sitemesh decorator in where the custom from my decorated page will be placed (as you can understand I come from the django world :p). Is this possible ? Do you propose anything else or should I just put my jquery.js in the header and be done with it ?
To answer my question, after some search I found the following solution:
I Added the following to the end of my decorator page (after including jquery.js)
<decorator:getProperty property="page.local_script"></decorator:getProperty>
I also added the following
<content tag="local_script">
<script>
$(function() {
alert("Starting");
});
</script>
</content>
The decorated result page contained the contents of the local_script tag exactly where I wanted them and everything worked fine :)
I don't know why this feature of sitemesh is not properly documented - using this you can have a great templating behaviour (like django).
I would like to basically do what Jason asked for here
In one sentence, I would like the url bar to represent the state of the AJAX application so that I can allow to bookmark it as well as allow the user to return to the previous state by using the back/forward buttons in the browser.
The difference for me (From what Jason asked) is that I am using JSF 2.0.
I've read that JSF 2.0 added the ability to use get, but I am not sure what the correct way to use this.
Thanks for the help.
Further Clarification
If I understand correctly, to be able to bookmark specific states in the AJAX webapp I will have to use the location.hash. Am I correct? I'm trying to achieve a gmail-like behaviour in the sense that, while the app is complete AJAXified and no redirects occur, I can still use Back/Forward and bookmark (And that's why I would like the URL bar to be updated from the AJAX app itself and not through redirection)
Update
Just found this similar question
The difference for me (From what Jason asked) is that I am using JSF 2.0. I've read that JSF 2.0 added the ability to use get, but I am not sure what the correct way to use this.
Please note that this is not the same as maintaining the Ajax state. It usually happens by fragment identifiers (the part starting with # in URL, also known as hashbang). JSF doesn't offer builtin components/functionality for this. As far I have also not seen a component library which does that. You may however find this answer useful to get started with a homegrown hash fragment processor in JSF.
As to using GET requests, just use <h:link>, <h:outputLink> or even <a> to create GET links. You can supply request parameters in the h: components by <f:param>. E.g.
<h:link value="Edit product" outcome="product/edit">
<f:param name="id" value="#{product.id}" />
</h:link>
In the product/edit.xhtml page you can define parameters to set and actions to execute upon a GET request
<f:metadata>
<f:viewParam name="id" value="#{productEditor.id}" />
<f:event type="preRenderView" listener="#{productEditor.init}" />
</f:metadata>
In the request or view scoped bean associated with product/edit.xhtml page -in this example #{productEditor}-, you just define the properties and the listener method. The listener method will be executed after all properties are been gathered, converted, validated and updated in the model.
private Long id;
private Product product;
public void init() {
product = productService.find(id);
}
Normally you'd use AJAX to prevent complete page refreshes. AFAIK all current browsers would issue a page refresh if you change the base uri. Thus you would have to use the hash part as suggested in the question you provided.
We had a similar problem and did something like this:
We settled for the fact that users cannot bookmark the url.
For URLs that should be unique/bookmarkable we used different links that issue a redirect. Those URLs are provided in a sitemap.
For browser back, we added an intermediate page after login. This page does navigation and a redirect to the application. The navigation is stored in the session and when the server gets a navigation request (which can be a history back) the corresponding state is restored. A browser back opens that intermediate page which issues a redirect along with a navigation request on the server side.
I'm not a Java developer, but work with a team that is using JSF 1.2
We'd like to start using HTML 5 tags and attributes. It does not appear that JSF 1.2 supports those by default.
Is there anyway to have a JSF text tag:
<x:inputText>
spit out an html 5 search tag:
<input type="search" placeholder="blahblah" />
Right now, I'm having to let it output a regular text field and then I place inline JS after it to trigger a function that converts it client side:
<input type="text">
<script> funciton here that changes type to 'search' and adds placeholder attribute</script>
It works, but is a bit hacky. Is there a legitimate way to get server-side JSF to output proper HTML 5 tags?
Create a custom component. This allows you fine grained control over rendered HTML.
Or upgrade to JSF 2.0, then you can create a composite component which is a lot easier.
I'm writing a testing utility- I want to show multiple finished HTML "pages" in a single browser window.
Is this possible? I'm using Java Servlets.
For example, normally the user goes to a utility screen, fills in a bunch of fields and POSTS this to my servlet, which builds up a full HTML stream based on their input and writes it to HttpServletResponse.getWriter(). When the user views source, they get a <html> ... </html>.
What I want to do is allow users to request multiple "screens" and get the results in a single web page where you'd scroll down to see the 2nd, 3rd, etc. screens, maybe there is some kind of divider in between. I thought of frames or iframes, but didn't have luck. I have seen where I can write my big html stream to a javascript variable, then use document.write to dump it into the iframe. But that seems pretty awkward, and I'd have to be really careful about escaping quotes and stuff.
You will have to use iframes or frames to do this. A single web page can only contain one set of html tags and thus one html page.
Another idea would be to render the page by your script and then capture a picture of it and then have a page containing images. You will of course loose all interaction with the page.
I'm not sure what you're trying with your frames, but I imagine frames should work OK for what you've described.
Instead of trying to post to more than one URL from your form, you just post to a servlet that returns a page with the frameset, and each frame has a source that points to one of the URLs you want to test. For example:
<form action="testServlet" method="post">
<input type="text" name="someValue" />
</form>
The testServlet then returns a page with this content:
<frameset rows="33%,33%,33%">
<frame src="testUrl1?someValue=value">
<frame src="testUrl2?someValue=value">
<frame src="testUrl3?someValue=value">
</frameset>
The only problem with this is that you're doing a GET instead of a POST, but that's easy to get around. All you would need do is to implement the doGet method within your servlets and just call doPost from within doGet.
Just leave out the <html>/</html> tags for each page and wrap the whole thing inside a single large ....
Like this maybe:
<html>
[page1Content]
<hr />
[page2Content]
<hr />
[page3Content]
<hr />
</html>
Do anyone know how to put Google adsense ads inside a GWT web application?
You can put the javascript-code from Adsense in the single HTML page that GWT starts with. This way the advertising will not be displayed in the same area as GTW but above/below the GWT code. For advertising that could be ok.
This example places a baner above the application:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>www.javaoracleblog.com</title>
<script type="text/javascript" language="javascript" src="com.javaoracleblog.aggregator.nocache.js"></script>
</head>
<body>
<script type="text/javascript"..
ADsense code here
</script>
<!-- OPTIONAL: include this if you want history support -->
<iframe src="javascript:''" id="__gwt_historyFrame" tabIndex='-1' style="position:absolute;width:0;height:0;border:0"></iframe>
</body>
</html>
In order to indicate to Google WT that the site of Google adsense can be trusted you need to add a regex matching URL to the -whitelist command line argument.
Note that this will probably not solve the problems desribed in the above "Why I dumped GWT" article.
According to this thread on AdSense:
Short version, you can't use Adsense
via Ajax without breaking the
programme policies/t&c's
Long version...
Ad code passed through an xmlhttp call
is not rendered, it's just treated as
text (hence, responseText). The only
way to execute js code is to use
"responseXML" coupled with the
"exec()" command.
For instance...
If your xml contains something along
the lines of:
This is the
content from the external
file javascript code
goes here
You would assign a variable (called
page_data for instance) using
ajax_obj.responseXML, run the XML
through a parser and run
exec(js variable or line from XML
here);
Not really helpful from an Adsense
standpoint, but that's how it's done.
It's also worth mentioning Why I dumped GWT:
Another problem were my adsense
banners. Since I didn’t have a lot of
content on the page, the banners were
sometimes off topic. An even bigger
problem was that the banners stayed
the same when people searched for
different keywords (since the ajax
refresh didn’t trigger an adsense
refresh). I solved this by doing the
search with a page refresh instead of
an ajax call. The ajax part of the
site was limited to sorting, faceting,
i18n and displaying tips.
You might check out the interview I did with InfoQ. It includes a sample chapter from my book and it happens to be on SEO.
It's not trivial, but I think the solutions in the chapter let GWT work nicely in an environment where SEO is important. The basic solution is to implement something I call 'bootstrapping'. This means that your pages take the info that would normally come across in GWT-RPC requests and serialize them into the page. The GWT widget then loads this information without an RPC request. While your page serializes the info into JavaScript, it's easy to also write a <noscript> to the page that can be used for SEO.
Take a look at the PDF included here: InfoQ GWT it goes into all the detail. The whole sample project is here: google code with source on github.
If you really want AdSense to be kinda "inside" GWT I'd use the Frame widget. Basically the Frame widget generates an <iframe ...> inside your GWT code. First I've thought iframe, UGH! But the <iframe> tag is still part of the HTML5 spec and has been even extended by some attributes that seem to be there for exactly this "sandboxing" purpose. And with corresponding CSS styling you will not have any scrollbars around your <iframe>.
And here is the actual solution:
You should put
<ui:style>
.sponsor {
border: 0em;
width: 20em;
height: 6em;
float: right;
display: inline;
}
</ui:style>
<g:HTMLPanel>
<g:Frame ui:field="sponsor" url="issue/extern/Google-AdSense.html" styleName="{style.sponsor}"/>
</g:HTMLPanel>
into your .ui.xml file and the logic into the corresponding .java file:
#UiField
Frame sponsor;
Also you should put the actual Google AdSense code (the <script> stuff) into a separate HTML file inside GWT's public folder which is - in this case - called Google-AdSense.html and is located inside the extern folder inside the public folder. issue (in the Frame url attribute) is in this case the GWT output folder.
And here is how it looks like: The ad in the upper right corner.
Btw this is also the way to embed the Google Analytics code into GWT.
Here is how I do it. I have a demo and source code here: http://code.google.com/p/gwt-examples/wiki/DemoGwtAdsene
You can use AdSense and GWT together without using frames or other hacks if you take some care in how you create your host pages.
The key is to include your AdSense code in the host page and then to manipulate the dom element containing the ad but to not detach it from the page. So you can reposition the ads into the body of your other gwt code as long as the dom structure is not changed.
If you do detach and reattach the containing dom element then it will appear to work in Chrome and Firefox but IE will show a blank space. I tried initially to move the ads DIV element into a DockLayoutPanel and thought everything was great until I belatedly tested it in IE.
So this is OK:
Element element = Document.get().getElmentById("ad");
element.getStyle().setPosition(ABSOLUTE);
element.getStyle().setTop(20, PX);
But this is not:
myPanel.add(ElementWrapper.wrap(element));
because adding a widget to another widget re-parents it.
This means that you cannot use any of the built-in LayoutPanel stuff to hold your ad div because Layout cannot wrap an existing element (It creates its own DIV in its constructor). You may be able to modify the layout panel stuff so it wraps an element and does not re-parent it... but I have not tried this yet.
I've tested the results in IE6+, Chrome and Firefox. Downside is that you cannot refresh the ads unless you load a new page. But in my case GWT was used to enhance html pages so that was not an issue. In any case... are users more likely to click on a different ad than one they read several times? Not sure it is so vital.
I could do this using DFP Small Business + Async Publisher tag + AdSense integration:
Here is the code:
On of your host page, put your publisher tag, something like:
<head>
<script type="text/javascript" src="http://www.googletagservices.com/tag/js/gpt.js"></script>
<script type="text/javascript">
var slot1 = googletag.defineUnit('/XXXX/ca-pub-YYYYYYYYYYYYYYY/transaction', [468, 60], 'div-gpt-ad-ZZZZZZZ-0').addService(googletag.pubads());
googletag.pubads().enableSingleRequest();
googletag.enableServices();
</script>
...
</head>
I've created a view with uiBinder, with a div with the id specified at the head, like this:
<g:HTMLPanel height="62px" width="100%">
<div id='div-gpt-ad-ZZZZZZZ-0' style='width:470px; height:60px;'>
</div>
</g:HTMLPanel>
On the onLoad() method of the view, you initialize the ad, like this:
#Override
protected void onLoad() {
setupAd();
}
public static native void setupAd() /*-{
$wnd.googletag.cmd.push(function() {$wnd.googletag.display('div-gpt-ad-ZZZZZZZ-0')});
}-*/;
To refresh the ad, just call refresh ad for the slot specified at head:
public static native void refreshAd() /*-{
$wnd.googletag.pubads().refresh([$wnd.slot1]);
}-*/;
That's all!
For more information about the publisher tag, check:
http://support.google.com/dfp_sb/bin/answer.py?hl=en&answer=1649768
Now I'm struggling to know how to make AdSense bot to craw my ajax application. I've implemented the Ajax Crawling scheme:
https://developers.google.com/webmasters/ajax-crawling/docs/getting-started
But I've got the information from AdSense forum that the AdSense bot (Mediapartners-Google) doesn't work with "escaped fragment" Ajax scheme.
Does anybody know if Google plan to make any progress on that?
This limits this approach to serve just interest based ads, since the context based ad serving depends on ajax crawling scheme.
Google's AdSense bot crawls your page to determine what ads to serve. Therefore, you should not put AdSense on pages with mostly dynamic content. It won't work well.
Maybe you should look into other ad programs?