Can we change the name of faces-config.xml file or it should be the same name ?
In jsf 1.2 , default suffix is .jsp and jsf 2.0 default suffix is .xhtml? Can we have a default suffix as .jsf
What is the use of the below line?
<listener>
<listener-class>com.sun.faces.config.ConfigureListener</listener-class>
</listener> here
How to get a managed bean name, scope and request url programatically?
I have 1000 records in my database but i just want to show the records from 100 to 200 (in a jsf datatable? How can i do that?
How a request works in jsf?
What is re-render and rendered attributes? what is the use of those?
difference between f:param and f:attribute? where and when we use those?
Do we use none scope? in what scenario it will be used?
Can we change the name of faces-config.xml file
Yes, but then it ceases to be a faces-config.xml file. It's hard to see why you're even asking.
or it should be the same name?
If you want it to work, yes.
In jsf 1.2 , default suffix is .jsp and jsf 2.0 default suffix is .xhtml? Can we have a default suffix as .jsf
Yes.
What is the use of the below line?
<listener> <listener-class>com.sun.faces.config.ConfigureListener</listener-class> </listener> here
See this answer, which you could have found for yourself.
How to get a managed bean name, scope and request url programatically?
The name of a managed bean is fixed when you compile it, so I don't know why you're even asking. I don't know what 'get a scope' means. You can get the request URL from the ExternalContext.
I have 1000 records in my database but i just want to show the records from 100 to 200 (in a jsf datatable? How can i do that?
With a LIMIT clause in your SQL.
How a request works in jsf?
Far too broad to answer here.
What is re-render and rendered attributes?
reRender is part of RichFaces. rendered is part of JSF.
what is the use of those?
These things are documented. There's no need to ask about things like that here.
difference between f:param and f:attribute?
Ditto.
where and when we use those?
Ditto.
Do we use none scope?
If you need it.
in what scenario it will be used?
When you don't need any other scope.
This questions are pretty frivolous. You could have more usefully spent the time doing some research of your own. Don't let me stop you.
Related
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?
What is the difference between those approaches?
Facelet templates
Use Facelet templates (as in <ui:composition>, <ui:include> and <ui:decorate>) if you want to split main page layout fragments into reuseable templates. E.g. header, menu, content, footer, etc.
Examples:
How to include another XHTML in XHTML using JSF 2.0 Facelets?
What is the real conceptual difference between ui:decorate and ui:include?
How to customize h:head when using ui:composition template?
How to change head elements of a page when using ui:composition
How to ajax-refresh dynamic include content by navigation menu? (JSF SPA)
Facelet tag files
Use Facelet tag files if you want to have a reuseable group of components in order to prevent/minimize code duplication. E.g. a group of label+input+message components. The major difference with composite components is that the output of a Facelet tag file does not represent a single UIComponent and may in some circumstances be the only solution when a composite component doesn't suffice. Generally, having an <ui:include> with one or more <ui:param> which passes a managed bean property (and thus not a hardcoded value) is a signal that the include file can better be a tag file.
Examples:
How to create a custom Facelets tag?
How to make a grid of JSF composite component?
How to create a composite component for a datatable column?
Primefaces outputLabel for composite component
Composite components
Use composite components if you want to create a single and reuseable custom UIComponent with a single responsibility using pure XML. Such a composite component usually consists of a bunch of existing components and/or HTML and get physically rendered as single component and is supposed to be bound to a single bean property. E.g. a component which represents a single java.time.LocalDate property by 3 dependent <h:selectOneMenu> components representing day, month and year, or a component which combines <p:fileUpload> and <p:imageCropper> into a single <my:uploadAndCropImage> referring a single custom com.example.Image entity as property.
Examples:
Our Composite Component wiki page
The BalusC Code: Composite Component with multiple input fields
Split java.util.Date over two h:inputText fields representing hour and minute with f:convertDateTime
Select all items in Multiple SelectManyCheckBox with dynamic ids
Extending JSF commandLink component
Avoiding duplicate ids when reusing facelets compositions in the same naming container
Custom components
Use a custom component whenever the functionality cannot be achieved with Facelet tag files or composite components, because of the lack of support in the standard/available set of components. Generally when you want a high degree of control and/or customization of the decoding and/or encoding, and also to offer the endusers the possibility to relatively easily extend/override the decoding and/or encoding. Examples can be found over all place in source code of open source component libraries such as PrimeFaces and OmniFaces.
Tag handlers
When you want to control the building of the JSF component tree instead of rendering of the HTML output, then you should use a tag handler instead of a component.
Examples:
Custom Facelet component in JSF
How can I access the content of something created with <ui:define> programmatically?
Conditional render in tagfile depending on whether the attribute is specified or not
Performing a redirect, when conversion / validation associated with query parameters fails
Example projects
Here are some example projects which utilize all of above mentioned techniques.
Java EE Kickoff App (templates - includes - tagfiles - composite)
OmniFaces Showcase (templates - includes - tagfiles - composite)
Could performance differ?
Technically, the performance concern is negligible. The choice should be made based on the concrete functional requirements and the final degree of abstraction, reusability and maintainability of the implementation. Each approach has its own well definied purpose and limitations.
Composite components do however have a significant overhead during building/restoring of the view (specifically: during saving/restoring the view state). And, in older versions of Mojarra, composite components had performance issues with assigning default values, this is already fixed since 2.1.13. Also, Mojarra had a memory leak when a <cc:attribute method-signature> is used for method expressions, basically the entire component tree is re-referenced in HTTP session, this is fixed since 2.1.29 / 2.2.8. The memory leak can be bypassed in older 2.1 versions as below:
<context-param>
<param-name>com.sun.faces.serializeServerState</param-name>
<param-value>true</param-value>
</context-param>
Or in older 2.2 versions as below:
<context-param>
<param-name>javax.faces.SERIALIZE_SERVER_STATE</param-name>
<param-value>true</param-value>
</context-param>
Still, when you have relatively "a lot of" composite components, and you have javax.faces.STATE_SAVING_METHOD set to client, then the performance will be a pain. Do not abuse composite components if you merely want the basic functionality which is already possible with a simple include file or tag file. Do not use the ease of configuration (read: no *.taglib.xml file needed) as an excuse to prefer composite components over tag files.
When using Mojarra 2.2.10 or older, do not forget to disable the relatively short Facelets refresh period for production mode:
<context-param>
<param-name>javax.faces.FACELETS_REFRESH_PERIOD</param-name>
<param-value>-1</param-value>
</context-param>
Do not use this setting for development, otherwise you've to restart the whole server to get changes in Facelets files to be reflected! Mojarra 2.2.11 and newer, and MyFaces already defaults to -1 when javax.faces.PROJECT_STAGE is not set to Development.
I am using PrimeFaces and JSF - I need to be able to set a component on the page as mandatory in response to an AJAX event. Is the best way to accomplish this using the following code or is there also a way to accomplish it using JQuery ?
Thanks
UIInput componentToChange = (UIInput) facesContext.getViewRoot().findComponent("ComponentId");
componentToChange.setRequired(true);
Thanks
Just set the component's required attribute with the desired EL expression.
E.g.
<h:inputText ... required="#{bean.required}" />
There are even EL ways without needing an additional bean property, but it's impossible to propose one based on the sparse information provided so far.
Use findComponent() with care. Think twice if it really can't be done just in the view (XHTML) side.
I am new to JSF and getting very confused doing something trivial. I am making up this example here to elaborate what I am want to do:
I have a xhtml fragment, say, stockQuoteFragment.xhtml, which is backed by a ManagedBean, say, StockQuoteService.java. StockQuoteService.java has property stockID and a method getStockQuote() which has all the logic to get the stockQuote for the value set on stockID property. stockQuoteFragment.xhtml displays #stockQuoteService.stockQuote.
Now I have another page Home.xhtml page with backing bean HomeBackingBean.java with a method getUserFavoriteStockID(). I want to include content of stockQuoteFragment.xhtml in Home.xhtml passing in the value of #homeBackingBean.userFavoriteStockID to StockQuoteService.setStockID().
I am not sure how to do this in JSF/Facelets. With simple JSPs I could do this easily with a JSP include and include parameters
No.
...According to TLD or attribute directive in tag file, attribute var does not accept any expressions.
I have just tried it.
But if you use pure XML based JSF with tags, you can easily use <ui:param> as discussed here. I use JSF in JSP and for me there is no help (<c:set> is mostly useless).
Can I just do this in Home.xhtml before I ui:include stockQuoteFragment.xhtml into it:
<c:set var="#{StockQuoteService.stockID}" value="#homeBackingBean.userFavoriteStockID"/>
will that work?
I am using a datatable and for each row I have two buttons, an "Edit" and a "Delete".
I need these buttons to be read-only, i.e. disabled, if a certain condition is met for the row in question. I have seen in JSF 2 that it is possible to pass parameters to method calls. Is there anything equivalent in JSF 1.2?
Ideally what I would like it something like (the looping variable is loop and there is another bean, helper, which contains the method I would like to invoke):
<h:commandButton value="Edit"
disabled="#{helper.isEditable(loop.id)}" />
In this case it does not make semantic sense to add an isEditable attribute to the bean and it is not practical to create a wrapper Object around the bean.
Thanks in advance.
I have seen in JSF 2 that it is possible to pass parameters to method calls. Is there anything equivalent in JSF 1.2?
Passing parameters to method calls is not specific to JSF 2. It is specific to EL 2.2, which is in turn part of JSP 2.2 / Servlet 3.0 / Java EE 6. JSF 2 just happens to be part of Java EE 6 as well. In other words, if you deploy your JSF 1.2 web application to a Servlet 3.0 compatible container like Tomcat 7, Glassfish 3, etc and your web.xml is declared conform Servlet 3.0 spec version, then it'll just work out the box for JSF 1.x as well.
If you're however still targeting a container of an older Servlet version, then you need to supply a different EL implementation which supports invoking methods with arguments. One of those implementations is JBoss-EL which you can install by just dropping the jboss-el.jar file in /WEB-INF/lib of your webapp and adding the following context parameter to the web.xml. Here's a Mojarra-specific example (Mojarra is the codename of JSF RI):
<context-param>
<param-name>com.sun.faces.expressionFactory</param-name>
<param-value>org.jboss.el.ExpressionFactoryImpl</param-value>
</context-param>
If you're using MyFaces as JSF implementation, you need the following context parameter instead:
<context-param>
<param-name>org.apache.myfaces.EXPRESSION_FACTORY</param-name>
<param-value>org.jboss.el.ExpressionFactoryImpl</param-value>
</context-param>
See also:
Invoke direct methods or methods with arguments / variables / parameters in EL
What is or could be a best practice?
Using standard JSF components and combine them by PrimeFaces components when needed (for example when DHTML or AJAX components are needed)
Forget all JSF Components and try to use all PrimeFaces components as much as possible
Please explain it and tell me about your experiences.
Thanks in advance...
PrimeFaces is your AJAX framework, so if you need to send ajaxical request, then use PrimeFaces components.
Even though, you dont need to send ajax request, but you can still use PF component, if u need to provide a consistency look for your web page. For example, h:commandButton and p:commandButton. Use p:commandButton if u need to send ajax request, but u can also do this
<p:commandButton ajax="false" action="Your Action here"/>
This will provide the same result as:
<h:commandButton action="Your Action here"/>
but this way, you can provide the same consistent look for your button throughout the page.
PrimeFaces does not have replacements for h:panelGrid, h:panelGroup, h:inputText, h:outputText ...
Depends on the sole functional requirement. If you're already using PrimeFaces and whatever you want to achieve can better/easier be achieved using a PrimeFaces component, use it.
Option 1 comes close, but option 2 goes overboard. PrimeFaces for example doesn't have a <p:form>, <p:panelGroup>, <p:outputText> or something.
With Primefaces it's very easy to get a consistent look for your application since it comes with Themeroller CSS framework. And you can easily switch designs. Although it is not difficult to let plain jsf components look like primefaces components if you apply the right css classes.
I think primefaces is a great component library. However some components are still buggy (e.g. date picker). So if you get some unexpected behavior with a primefaces component, it is alway good to have a jsf fallback (or an alternative from another component library or from jquery).
I have no experience with mixing different component libraries. Would be interesting to know, how they interact. But that would be subject of another question ...