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When should I use h:outputLink instead of h:commandLink?

When should I use an <h:outputLink> instead of an <h:commandLink>?

I understand that a commandLink generates an HTTP post; I'm guessing that outputLink will generate HTTP gets. That said, most of the JSF tutorial material I've read uses commandLink (almost?) exclusively.

Context: I am implementing a wee little demo project that shows a header link to a user page, much like Stack Overflow's...

...and I am not sure if commandLink (perhaps using ?faces-redirect=true for bookmarkability) or outputLink is the right choice.

How can I pass selected row to commandLink inside dataTable?

I'm using Primefaces in a JSF 2 application. I have a <p:dataTable>, and instead of selecting rows, I want the user to be able to directly execute various actions on individual rows. For that, I have several <p:commandLink>s in the last column.

My problem: how can I pass a row ID to the action started by the command link so that I know which row to act on? I tried using an <f:attribute>:

<p:dataTable value="#{bean.items}" var="item">
    ...
    <p:column>
        <p:commandLink actionListener="#{bean.insert}" value="insert">
            <f:attribute name="id" value="#{item.id}" />
        </p:commandLink>
    </p:column>
</p:dataTable>

But it always yields 0 - apparently the row variable f is not available when the attribute is rendered (it works when I use a fixed value).

Anyone has an alternative solution?

What is the JSF resource library for and how should it be used?

The JSF <h:outputStylesheet>, <h:outputScript> and <h:graphicImage> components have a library attribute. What is this and how should this be used? There are a lot of examples on the web which use it as follows with the common content/file type css, js and img (or image) as library name depending on the tag used:

<h:outputStylesheet library="css" name="style.css" />
<h:outputScript library="js" name="script.js" />
<h:graphicImage library="img" name="logo.png" />

How is it useful? The library value in those examples seems to be just repeating whatever is already been represented by the tag name. For a <h:outputStylesheet> it's based on the tag name already obvious that it represents a "CSS library". What's the difference with the following which also just works the same way?

<h:outputStylesheet name="css/style.css" />
<h:outputScript name="js/script.js" />
<h:graphicImage name="img/logo.png" />

Also, the generated HTML output is a bit different. Given a context path of /contextname and FacesServlet mapping on an URL pattern of *.xhtml, the former generates the following HTML with the library name as request parameter:

<link rel="stylesheet" type="text/css" rel='nofollow' href="/contextname/javax.faces.resource/style.css.xhtml?ln=css" />
<script type="text/javascript" src="/contextname/javax.faces.resource/script.js.xhtml?ln=js"></script>
<img src="/contextname/javax.faces.resource/logo.png.xhtml?ln=img" alt="" />

While the latter generates the following HTML with the library name just in the path of the URI:

<link rel="stylesheet" type="text/css" rel='nofollow' href="/contextname/javax.faces.resource/css/style.css.xhtml" />
<script type="text/javascript" src="/contextname/javax.faces.resource/js/script.js.xhtml"></script>
<img src="/contextname/javax.faces.resource/img/logo.png.xhtml" alt="" />

The latter approach makes in hindsight also more sense than the former approach. How exactly is the library attribute then useful?

What are the main disadvantages of Java Server Faces 2.0?

Yesterday I saw a presentation on Java Server Faces 2.0 which looked truly impressive, even though I am currently a happy ASP.NET MVC / jQuery developer. What I liked most about JSF was the huge amount of AJAX-Enabled UI components which seem to make development much faster than with ASP.NET MVC, especially on AJAX-heavy sites. Integration testing looked very nice too.

Since the presentation only emphasized the advantages of JSF, I'd like to hear about the other side as well.

So my questions are:

• What are the main disadvantages of Java Server Faces 2.0?
• What might make a JSF developer consider using ASP.NET MVC instead of JSF?

What can , and be used for?

Can anyone clarify how we can use in general, or a in real world example, this snippet?

<f:metadata>
    <f:viewParam id="id" value="#{bean.id}" />
    <f:viewAction action="#{bean.init}" />
</f:metadata>

Migrating from JSF 1.2 to JSF 2.0

I am working with a rather large app written in JSF 1.2. JSF 1.2 is around 6 years old now. I need to upgrade to JSF 2.0. How painful will this be? I noticed that some attributes in custom tags have been changed etc.

How to include another XHTML in XHTML using JSF 2.0 Facelets?

What is the most correct way to include another XHTML page in an XHTML page? I have been trying different ways, none of them are working.

How to choose the right bean scope?

I noticed that there are different bean scopes like:

@RequestScoped
@ViewScoped
@FlowScoped
@SessionScoped
@ApplicationScoped

What is the purpose of each? How do I choose a proper scope for my bean?

commandLink/commandButton/ajax backing bean action/listener method not invoked

I found a problem when using the <h:commandLink> or <h:commandButton> in an include page: the action and actionListener associated with the UICommand component are simply not being invoked. What are the possible causes and solutions for this?

Differences between action and actionListener

What is the difference between action and actionListener, and when should I use action versus actionListener?

JSTL in JSF2 Facelets... makes sense?

I would like to output a bit of Facelets code conditionally.

For that purpose, the JSTL tags seem to work fine:

<c:if test="${lpc.verbose}">
    ...
</c:if>

However, I'm not sure if this is a best practice? Is there another way to achieve my goal?

When to use , tag files, composite components and/or custom components?

I started using JSF 2.0 with Facelets recently and got puzzled by new composite components knowing existing <ui:include> and other templating techniques offered by Facelets 1.x.

What is the difference between those approaches? Functionally they seem to offer about the same: <ui:param> vs <cc:attribute>, <ui:insert>+<ui:define> vs tag files, reuse of the existing templates. Is there anything besides syntax and clear interface specification in case of composite components? Could performance differ?

Get JSF managed bean by name in any Servlet related class

I'm trying to write a custom servlet (for AJAX/JSON) in which I would like to reference my @ManagedBeans by name. I'm hoping to map:

http://host/app/myBean/myProperty

to:

@ManagedBean(name="myBean")
public class MyBean {
    public String getMyProperty();
}

Is it possible to load a bean by name from a regular servlet? Is there a JSF servlet or helper I could use for it?

I seem to be spoilt by Spring in which all this is too obvious.

How get the base URL?

I have this structure:

WebContent
    resources
        components
            top.xhtml

    company
        about_us.xhtml

    index.xhtml

top.xhtml is a component, that is used in index.xthml and about_us.xhtml too.

top.xhtml

<ul>
    <li><a rel='nofollow' href="index.xhtml">Home</a></li>
    <li><a rel='nofollow' href="company/about_us.xhtml">About us</a></li>
    ...
</ul>

So my problem is, when the current page is index.xhtml the component generates URLs correctly, but when the current page is about_us.xhtml, it generates wrong URLs. I cannot use relative path because it's going to generate the wrong URL too. I think it is because the component is based on the current path of the *.xhtml page.

The only solution I could found out is:

<ul>
    <li><a rel='nofollow' href="${pageContext.request.contextPath}/webname/index.xhtml">Home</a></li>
    <li><a rel='nofollow' href="${pageContext.request.contextPath}/webname/about_us.xhtml">About us</a></li>
    ...
</ul>

But I think is not 'elegant' at all. Any ideas?

How to invalidate session in JSF 2.0?

What is the best possible way to invalidate session within a JSF 2.0 application? I know JSF itself does not handle session. So far I could find

private void reset() {
    HttpSession session = (HttpSession) FacesContext.getCurrentInstance()
            .getExternalContext().getSession(false);
    session.invalidate();
}

1. Is this method correct? Is there a way without touching the ServletAPI?
2. Consider a scenario wherein a @SessionScoped UserBean handles the login-logout of a user. I have this method in the same bean. Now when I call the reset() method after I'm done with necessary DB updates, what will happen to my current session scoped bean? since even the bean itself is stored in HttpSession?