RichFaces CSS skin

# Basic concepts of the RichFaces Framework

## Introduction

The framework is implemented as a component library which adds Ajax capability into existing pages, so you don't need to write any JavaScript code or to replace existing components with new Ajax widgets. RichFaces enables page-wide Ajax support instead of the traditional component-wide support. Hence, you can define the event on the page that invokes an Ajax request and the areas of the page that should be synchronized with the JSF Component Tree after the Ajax request changes the data on the server according to the events fired on the client.

Next Figure shows how it works:

Request Processing flow

RichFaces allows to define (by means of JSF tags) different parts of a JSF page you wish to update with an Ajax request and provide a few options to send Ajax requests to the server. Also JSF page doesn't change from a "regular" JSF page and you don't need to write any JavaScript or XMLHttpRequest objects by hands, everything is done automatically.

## RichFaces Architecture Overview

Next figure lists several important elements of the RichFaces framework

Core Ajax component structure

Ajax Filter.

To get all benefits of RichFaces, you should register a Filter in web.xml file of your application. The Filter recognizes multiple request types. Necessary information about Filter configuration can be found in the "Filter configuration" section. The sequence diagram on Figure 3 shows the difference in processing of a "regular" JSF request and an Ajax request.

In the first case the whole JSF tree will be encoded, in the second one option it depends on the "size" of the Ajax region. As you can see, in the second case the filter parses the content of an Ajax response before sending it to the client side.

Have a look at the next picture to understand these two ways:

Request Processing sequence diagram

In both cases, the information about required static or dynamic resources that your application requests is registered in the ResourseBuilder class.

When a request for a resource comes (Figure 4), the RichFaces filter checks the Resource Cache for this resource and if it is there, the resource is sent to the client. Otherwise, the filter searches for the resource among those that are registered by the ResourceBuilder. If the resource is registered, the RichFaces filter will send a request to the ResourceBuilder to create (deliver) the resource.

Next Figure shows the ways of resource request processing.

Resource request sequence diagram

AJAX Action Components

There are Ajax Action Components: AjaxCommandButton, AjaxCommandLink, AjaxPoll and AjaxSupport and etc. You can use them to send Ajax requests from the client side.

AJAX Containers

AjaxContainer is an interface that describes an area on your JSF page that should be decoded during an Ajax request. AjaxViewRoot and AjaxRegion are implementations of this interface.

JavaScript Engine

RichFaces JavaScript Engine runs on the client-side. It knows how to update different areas on your JSF page based on the information from the Ajax response. Do not use this JavaScript code directly, as it is available automatically.

## Limitations and Rules

In order to create RichFaces applications properly, keep the following points in mind:

- Any Ajax framework should not append or delete, but only replace elements on the page. For successful updates, an element with the same ID as in the response must exist on the page. If you'd like to append any code to a page, put in a placeholder for it (any empty element). For the same reason, it's recommended to place messages in the "AjaxOutput" component (as no messages is also a message).
- Don't use <f:verbatim> for self-rendered containers, since this component is transient and not saved in the tree.
- Ajax requests are made by XMLHttpRequest functions in XML format, but this XML bypasses most validations and the corrections that might be made in a browser. Thus, create only a strict standards-compliant code for HTML and XHTML, without skipping any required elements or attributes. Any necessary XML corrections are automatically made by the XML filter on the server, but lot's of unexpected effects can be produced by an incorrect HTML code.

## Ajax Request Optimization

### Re-Rendering

Ajax attributes are common for Ajax components such as <a4j:support> , <a4j:commandButton> , <a4j:jsFunction> , <a4j:poll> , <a4j:push> and so on. Also, most RichFaces components with built-in Ajax support have these attributes for a similar purpose. Ajax components attributes help RichFaces to expose its features. Most of the attributes have default values. Thus, you can start working with RichFaces without knowing the usage of these attribute. However, their usage allows to tune the required Ajax behavior very smoothly.

"reRender" is a key attribute. The attribute allows to point to area(s) on a page that should be updated as a response on Ajax interaction. The value of the "reRender" attribute is an id of the JSF component or an id list.

A simple example is placed below:

    ...
            <a4j:commandButton value="update" reRender="infoBlock"/>
                ...
            <h:panelGrid id="infoBlock">
                ...
            </h:panelGrid>
    ...

The value of "reRender" attribute of the <a4j:commandButton> tag defines which part(s) of your page is (are) to be updated. In this case, the only part of the page to update is the <h:panelGrid> tag because its ID value matches to the value of "reRender" attribute. As you see, it's not difficult to update multiple elements on the page, only list their IDs as the value of "reRender" .

"reRender" uses UIComponent.findComponent() algorithm (with some additional exceptions) to find the component in the component tree. As can you see, the algorithm presumes several steps. Each other step is used if the previous step is not successful. Therefore, you can define how fast the component is found mentioning it more precisely. The following example shows the difference in approaches (both buttons will work successfully):

    ...
        <h:form id="form1">
            ...
            <a4j: commandButton value="Usual Way" reRender="infoBlock, infoBlock2" />
            <a4j:commandButton value="Shortcut" reRender=":infoBlockl,:sv:infoBlock2" />
            ...
        </h:form>
        <h:panelGrid id="infoBlock">
            ...
        </h:panelGrid>
        ...
        <f:subview id="sv">
          <h:panelGrid id="infoBlock2">
            ...
          </h:panelGrid>
          ...
        </f:subview>
    ...

It's also possible to use JSF EL expression as a value of the reRender attribute. It might be a property of types Set, Collection, Array or simple String. The EL for reRender is resolved right before the Render Response phase. Hence, you can calculate what should be re-rendered on any previous phase during the Ajax request processing.

Most common problem with using reRender is pointing it to the component that has a "reRender" attribute. Note, that JSF does not mark the place in the browser DOM where the outcome of the component should be placed in case the "rendered" condition returns false. Therefore, after the component becomes rendered during the Ajax request, RichFaces delivers the rendered code to the client, but does not update a page, because the place for update is unknown. You need to point to one of the parent components that has no "rendered" attribute. As an alternative, you can wrap the component with <a4j:outputPanel> layout="none".

"ajaxRendered" attribute of the <a4j:outputPanel> set to "true" allows to define the area of the page that will be re-rendered even if it is not pointed in the reRender attribute explicitly. It might be useful if you have an area on a page that should be updated as a response on any Ajax request. For example, the following code allows to output error messages regardless of what Ajax request causes the Validation phase failed.

    ...
         <a4j:outputPanel ajaxRendered="true">
            <h:messages />
        </a4j:outputPanel>
    ...

"limitToList" attribute allows to dismiss the behavior of the <a4j:outputPanel> "ajaxRendered" attribute. "limitToList" = "false" means to update only the area(s) that mentioned in the "reRender" attribute explicitly. All output panels with "ajaxRendered"="true"is ignored. An example is placed below:

    ...
        <h:form>
           <h:inputText value="#{person.name}">
                <a4j:support event="onkeyup" reRender="test" limitToList="true"/>
            </h:inputText>
            <h:outputText value="#{person.name}" id="test"/>
        </form>
    ...

### Queue and Traffic Flood Protection

"eventsQueue" attribute defines the name of the queue that will be used to order upcoming Ajax requests. By default, RichFaces does not queue Ajax requests. If events are produced simultaneously, they will come to the server simultaneously. JSF implementations (especially, the very first ones) does not guaranty that the request that comes first will be served or passed into the JSF lifecycle first. The order how the server side data will be modified in case of simultaneous request might be unpredictable. Usage of eventsQueue attribute allows to avoid possible mess. Define the queue name explicitly, if you expect intensive Ajax traffic in your application.

The next request posted in the same queue will wait until the previos one is not processed and Ajax Response is returned back if the "eventsQueue" attribute is defined. In addition, Richfaces starts to remove from the queue "similar" requests. "Similar'"requests are the requests produced by the same event. For example, according to the following code, only the newest request will be sent to the server if a user types very fast and has typed the several characters already before the previous Ajax Response is back.

    ...
        <h:inputText value="#{userBean.name}">
            <a4j:support event="onkeyup" eventsQueue="foo" reRender="bar" />
        </h:inputText>
    ...

"requestDelay" attribute defines the time (in ms) that the request will be wait in the queue before it is ready to send. When the delay time is over, the request will be sent to the server or removed if the newest "similar" request is in a queue already .

"ignoreDupResponses" attribute orders to ignore the Ajax Response produced by the request if the newest "similar" request is in a queue already. "ignoreDupResponses"="true" does not cancel the request while it is processed on the server, but just allows to avoid unnecessary updates on the client side if the response loses the actuality.

Defining the "eventsQueue" along with "requestDelay" allows to protect against unnecessary traffic flood and synchronizes Ajax requests order. If you have several sources of Ajax requests, you can define the same queue name there. This might be very helpful if you have Ajax components that invoke request asynchronously from the ones produced by events from users. For example, <a4j:poll> or <a4j:push> . In case the requests from such components modify the same data, the synchronization might be very helpful.

More information can be found on the RichFaces Users Forum.

"timeout" attribute is used for setting response waiting time on a particular request. If a response is not received during this time, the request is aborted.

### Data Processing Options

RichFaces uses form based approach for Ajax request sending. This means each time, when a user click an Ajax button or <a4j:poll> produces an asynchronous request, the data from the closest JSF form is submitted with the XMLHTTPRequest object. The form data contains the values from the form input element and auxiliary information such as state saving data.

When "ajaxSingle" attribute value is "true", it orders to include only a value of the current component (along with <f:param> or <a4j:action> param values if any) to the request map. In case of <a4j:support> , it is a value of the parent component. An example is placed below:

    ...
        <h:form>
            <h:inputText value="#{person.name}">
                <a4j:support event="onkeyup" reRender="test" ajaxSingle="true"/>
            </h:inputText>
          <h:inputText value="#{person.middleName}"/>
        </form>
    ...

In this example the request contains only the input component causes the request generation, not all the components contained on a form, because of "ajaxSingle"="true" usage.

Note, that "ajaxSingle"="true" reduces the upcoming traffic, but does not prevent decoding other input components on the server side. Some JSF components, such as <h:selectOneMenu> do recognize the missing data in the request map value as a null value and try to pass the validation process with a failed result. Thus, use <a4j:region> to limit a part of the component tree that will be processed on the server side when it is required.

"immediate" attribute has the same purpose as any other non-JSF component. The default "ActionListener" should be executed immediately (i.e. during the Apply Request Values phase of a request processing lifecycle), rather than waiting until the Invoke Application phase. Using immediate="true" is one of the ways to have some data model values updated when other cannot be updated because of a problem with passing the Validation phase successfully. This might be important inside the <h:dataTable> like components where using <a4j:region> is impossible due to the <h:dataTable> component architecture.

"bypassUpdates" attribute allows to bypass the Update Model phase. It might be useful if you need to check user input against the available validator, but not to update the model with those data. Note, that an action will be invoked at the end of the Validation phase only if the Validation phase is passed successfully. The listeners of the Application phase will not be invoked in any case.

### Action and Navigation

Ajax component is similar to any other non-Ajax JSF component like <h:commandButton> . It allows to submit the form. You can use "action" and "actionListener" attribute to invoke the action method and define the action event.

"action" method must return null if you want to have an Ajax Response with a partual page update. This is regular mode called "Ajax request generates Ajax Response". In case of action does not return null, but the action outcome that matches one of navigation rules, RichFaces starts to work in "Ajax request generates Non-Ajax Response" mode. This mode might be helpful in two major cases:

- RichFaces allows to organize a page flow inside the <a4j:include> component. This is a typical scenario for Wizard like behavior. The new content is rendered inside the <a4j:include> area. The content is taken from the navigation rule of the faces configuration file (usually, the faces-config.xml). Note, that the content of the "wizard" is not isolated from the rest of the page. The included page should not have own <f:view> (it does not matter if you use facelets). You need to have an Ajax component inside the <a4j:include> to navigate between the wizard pages. Otherwize, the whole page update will be performed.
- If you want to involve the server side validators and navigate to the next page only if the Validation phase is passed successfully, you can replace <h:commandButton> with <a4j:commandButton> and point to the action method that navigates to the next page. If Validation process fails, the partial page update will occur and a user will see an error message. Otherwize, the application proceeds to the next page. Make sure, you define <redirect/> option for the navigation rule to avoid memory leaks.

### JavaScript Interactions

RichFaces allows writing Ajax-enabled JSF application without writing any Javascript code. However, you can still invoke the javascript code if you need. There are several ajax attributes that helps to do it.

"onsubmit" attribute allows to invoke JavaScript code before an Ajax request is sent. If "onsubmit" returns "false", the Ajax request is canceled. The code of "onsubmit" is inserted before the RichFaces Ajax call. Hence, the "onsubmit" should not has a "return" statement if you want the Ajax request to be sent. If you are going to invoke a JavaScript function that returns "true" or "false", use the conditional statement to return something only when you need to cancel the request. For example:

    ...
        onsubmit="if (mynosendfunct()==false){return false}"
    ...

"onclick" attribute is similar to the "onsubmit" , but for clickable components such as <a4j:commandLink> and <a4j:commandButton> . If it returns "false", the Ajax request is canceled also.

"oncomplete" attribute allows to invoke the JavaScript code right after the Ajax Response is returned back and the DOM tree of the browser is updated. Richfaces registers the code for further invocation of XMLHTTP request object before an Ajax request is sent. This means the code will not be changed during processing of the request on the server if you use JSF EL value binding. Also, you cannot use "this'" inside the code, because it will not point the component where Ajax request was initiated.

"onbeforedomupdate" attrubute defines JavaScript code for call after Ajax response receiving and before updating DOM on a client side.

"data" attribute allows to get the additional data from the server during an Ajax call. You can use JSF EL to point the property of the managed bean and its value will be serialized in JSON format and be available on the client side. You can refer to it using the "data" variable. For example:

    ...
        <a4j:commandButton value="Update" data="#{userBean.name}" oncomplete="showTheName(data.name)" />
    ...

Richfaces allows to serialize not only primitive types into JSON format, but also complex types including arrays and collections. The beans should be serializable to be refered with "data" .

### Iteration components Ajax attributes

"ajaxKeys" attribute defines strings that are updated after an Ajax request. It provides possibility to update several child components separately without updating the whole page.

    ...
        <a4j:poll intervall="1000" action="#{repeater.action}" reRender="text">
            <table>
                <tbody>
                    <a4j:repeat value="#{bean.props}" var="detail" ajaxKeys="#{repeater.ajaxedRowsSet}">
                        <tr>
                            <td>
                                <h:outputText value="detail.someProperty" id="text"/>
                            </td>
                        </tr>
                    </a4j:repeat>
                </tbody>
            </table>
        </a4j:poll>
    ...

### Other useful attributes

"status" attribute for Ajax components (such as <a4j:commandButton> , <a4j:poll> , etc.) points to an ID of <a4j:status> component. Use this attribute if you want to share <a4j:status> component between different Ajax components from different regions. The following example shows it.

    ...
        <a4j:region id="extr">
            <h:form>
                <h:outputText value="Status:" />
                <a4j:status id="commonstatus" startText="In Progress...." stopText=""/>
                <h:panelGrid columns="2">
                    <h:outputText value="Name"/>
                    <h:inputText id="name" value="#{userBean.name}">
                        <a4j:support event="onkeyup" reRender="out" />
                    </h:inputText>
                    <h:outputText value="Job"/>
                    <a4j:region  id="intr">
                        <h:inputText id="job" value="#{userBean.job}">
                            <a4j:support event="onkeyup"  reRender="out" status="commonstatus"/>
                       </h:inputText>
                    </a4j:region>
                </h:panelGrid>

                <a4j:region>
                    <h:outputText id="out" value="Name: #{userBean.name}, Job: #{userBean.job}" />
                    <br />
                    <a4j:commandButton ajaxSingle="true" value="Clean Up Form" reRender="name, job, out"  status="commonstatus">
                        <a4j:actionparam name="n" value=""  assignTo="#{userBean.name}" />
                        <a4j:actionparam name="j" value=""  assignTo="#{userBean.job}" />
                    </a4j:commandButton>
                </a4j:region>
            </h:form>
        </a4j:region>
    ...

In the example <a4j:support> and <a4j:commandButton> are defined in different regions. Values of "status" attribute for these components points to an ID of <a4j:support> .Thus, the <a4j:support> component is shared between two components from different regions.

More information could be found here.

Other useful attribute is "focus" . It points to an ID of a component where focus will be set after an Ajax request.

## How To...

### Send an Ajax request

There are different ways to send Ajax requests from your JSF page. For example you can use <a4j:commandButton> , <a4j:commandLink>, <a4j:poll> or <a4j:support> tags or any other.

All these tags hide the usual JavaScript activities that are required for an XMHttpRequest object building and an Ajax request sending. Also, they allow you to decide which components of your JSF page are to be re-rendered as a result of the Ajax response (you can list the IDs of these components in the "reRender" attribute).

<a4j:commandButton> and <a4j:commandLink> tags are used to send an Ajax request on "onclick" JavaScript event.

<a4j:poll> tag is used to send an Ajax request periodically using a timer.

The <a4j:support> tag allows you to add Ajax functionality to standard JSF components and send Ajax request onto a chosen JavaScript event: "onkeyup", "onmouseover", etc.

### Decide What to Send

You may describe a region on the page you wish to send to the server, in this way you can control what part of the JSF View is decoded on the server side when you send an Ajax request.

The easiest way to describe an Ajax region on your JSF page is to do nothing, because the content between the <f:view> and </f:view> tags is considered the default Ajax region.

You may define multiple Ajax regions on the JSF page (they can even be nested) by using the <a4j:region> tag.

If you wish to render the content of an Ajax response outside of the active region then the value of the "renderRegionOnly" attribute should be set to "false" ("false" is default value). Otherwise, your Ajax updates are limited to elements of the active region.

### Decide What to Change

Using IDs in the "reRender" attribute to define "AJAX zones" for update works fine in many cases.

But you can not use this approach if your page contains, e.g. a <f:verbatim> tag and you wish to update its content on an Ajax response.

The problem with the <f:verbatim/> tag as described above is related to the value of the transientFlag of JSF components. If the value of this flag is true, the component must not participate in state saving or restoring of process.

In order to provide a solution to this kind of problems, RichFaces uses the concept of an output panel that is defined by the <a4j:outputPanel> tag. If you put a <f:verbatim> tag inside of the output panel, then the content of the <f:verbatim/> tag and content of other panel's child tags could be updated on Ajax response. There are two ways to control this:

- By setting the "ajaxRendered" attribute value to "true".
- By setting the "reRender" attribute value of an Action Component to the output panel ID.

## Filter Configuration

RichFaces uses a filter for a correction of code received on an Ajax request. In case of a "regular" JSF request a browser makes correction independently. In case of Ajax request in order to prevent layout destruction it's needed to use a filter, because a received code could differ from a code validated by a browser and a browser doesn't make any corrections.

An example of how to set a Filter in a web.xml file of your application is placed below.

Example:

    ...
        <filter>
            <display-name>RichFaces Filter</display-name>
            <filter-name>richfaces</filter-name>
            <filter-class>org.ajax4jsf.Filter</filter-class>
        </filter>
    ...

Note:

Fast Filter is deprecated and available only for backward compatibility with previous RichFaces versions. Fast Filter usage isn't recomended, because there is another way to use its functionality by means of Neko filter type.

In RichFaces 3.1 filter configuration becomes more flexible. It's possible to configure different filters for different sets of pages for the same application.

The possible filter types are:

- TIDY

"TIDY" filter type based on the Tidy parser. This filter is recommended for applications with complicated or non-standard markup when all necessary code corrections are made by the filter when a response comes from the server.

- NEKO

"NEKO" filter type corresponds to the former "Fast Filter" and it's based on the Neko parser. In case of using this filter code isn't strictly verified. Use this one if you are sure that your application markup is really strict for this filter. Otherwise it could cause lot's of errors and corrupt a layout as a result. This filter considerably accelerates all Ajax requests processing.

- NONE

No correction.

An example of configuration is placed below.

Example:

    ...
        <context-param>
            <param-name>org.ajax4jsf.xmlparser.ORDER</param-name>
            <param-value>NONE,NEKO,TIDY</param-value>
        </context-param>

        <context-param>
            <param-name>org.ajax4jsf.xmlparser.NONE</param-name>
            <param-value>/pages/performance\.xhtml,/pages/default.*\.xhtml</param-value>
        </context-param>

        <context-param>
            <param-name>org.ajax4jsf.xmlparser.NEKO</param-name>
            <param-value>/pages/repeat\.xhtml</param-value>
        </context-param>

        <filter>
            <display-name>RichFaces Filter</display-name>
            <filter-name>richfaces</filter-name>
            <filter-class>org.ajax4jsf.Filter</filter-class>
        </filter>

        <filter-mapping>
            <filter-name>richfaces</filter-name>
            <servlet-name>Faces Servlet</servlet-name>
            <dispatcher>FORWARD</dispatcher>
            <dispatcher>REQUEST</dispatcher>
            <dispatcher>INCLUDE</dispatcher>
        </filter-mapping>
    ...

The example shows that ORDER parameter defines the order in which particular filter types are used for pages code correction.

First of all "NONE" type is specified for the filter. Then two different sets of pages are defined for which two filter types (NONE and NEKO) are used correspondingly. If a page relates to the first set that is defined in the following way:

    <param-value>/pages/performance\.xhtml,/pages/default.*\.xhtml</param-value>,

it's not corrected, because filter type for this page is defined as "NONE". If a page is not from the first set, then "NEKO" type is set.

If a page relates to the second set that is defined in the following way:

    <param-value>/pages/repeat\.xhtml</param-value>,

then "NEKO" filter type is used for correction. If it's not related to the second set, "TIDY" type is set for the filter ("TIDY" filter type is used for code correction).

## Request Errors and Session Expiration Handling

RichFaces allows to redefine standard handlers responsible for processing of different exceptional situations. It helps to define own JavaScript, which is executed when these situations occur.

### Request Errors Handling

To execute your own code on the client in case of an error during Ajax request, it's necessary to redefine the standard "A4J.AJAX.onError" method:

    A4J.AJAX.onError = function(req,status,message) {
              // Custom Developer Code
    };

The function defined this way accepts as parameters:

- req - a params string of a request that calls an error
- status - the number of an error returned by the server
- message - a default message for the given error

Thus, it's possible to create your own handler that is called on timeouts, inner server errors, and etc.

### Session Expired Handling

It's possible to redefine also the "onExpired" framework method that is called on the "Session Expiration" event.

Example:

    A4J.AJAX.onExpired = function(loc,expiredMsg){
              // Custom Developer Code
    };

Here the function receives in params:

- loc - URL of the current page (on demand can be updated)
- expiredMsg - a default message on "Session Expiration" event.

## Skinnability

### Why Skinnability

If you have a look at a CSS file in an enterprise application, for example, the one you're working on now, you'll see how often the same color is noted in it. Standard CSS has no way to define a particular color abstractly for defining as a panel header color, a background color of an active pop-up menu item, a separator color, etc. To define common interface styles, you have to copy the same values over and over again and the more interface elements you have the more copy-and-paste activity that needs to be performed.

Hence, if you want to change the application palette, you have to change all interrelating values, otherwise your interface can appear a bit clumsy. The chances of such an interface coming about is very high, as CSS editing usually becomes the duty of a general developer who doesn't necessarily have much knowledge of user interface design.

Moreover, if a customer wishes to have an interface look-and-feel that can be adjusted on-the-fly by an end user, your work is multiplied, as you have to deal with several CSS files variants, each of which contains the same values repeated numerous times.

These problems can be solved with the skinnability system built into theRichFaces project and realized fully in RichFaces. Every named skin has some skin-parameters for the definition of a palette and the other parameters of the user interface. By changing just a few parameters, you can alter the appearance of dozens of components in an application in a synchronized fashion without messing up user interface consistency.

The skinnability feature can't completely replace standard CSS and certainly doesn't eliminate its usage. Skinnability is a high-level extension of standard CSS, which can be used together with regular CSS declarations. You can also refer to skin parameters in CSS via JSF Expression Language. You have the complete ability to synchronize the appearance of all the elements in your pages.

### Using Skinnability

RichFaces skinnability is designed for mixed usage with:

- Skin parameters defined in the RichFaces framework

- Predefined CSS classes for components

- User style classes

The color scheme of the component can be applied to its elements using any of three style classes:

- A default style class inserted into the framework

  This contains style parameters linked to some constants from a skin. It is defined for every component and specifies a default representation level. Thus, an application interface could be modified by changing the values of skin parameters.

- A style class of skin extension

  This class name is defined for every component element and inserted into the framework to allow defining a class with the same name into its CSS files. Hence, the appearance of all components that use this class is extended.

- User style class

  It's possible to use one of the styleClass parameters for component elements and define your own class in it. As a result, the appearance of one particular component is changed according to a CSS style parameter specified in the class.

### Example

Here is a simple panel component:

Example:

    <rich:panel>
    ...
    </rich:panel>

The code generates a panel component on a page, which consists of two elements: a wrapper <div> element and a <div> element for the panel body with the particular style properties. The wrapper <div> element looks like:

Example:

    <div class="dr-pnl rich-panel">
    ...
    </div>

dr-pnl is a CSS class specified in the framework via skin parameters:

- background-color is defined with generalBackgroundColor

- border-color is defined with panelBorderColor

It's possible to change all colors for all panels on all pages by changing these skin parameters.

However, if a <rich-panel> class is specified somewhere on the page, its parameters are also acquired by all panels on this page.

A developer may also change the style properties for a particular panel. The following definition:

Example:

    <rich:panel styleClass="customClass">
    ...
    </rich:panel>

could add some style properties from customClass to one particular panel, as a result we get three styles:

Example:

    <div class="dr_pnl rich-panel customClass">
    ...
    </div>

### Skin Parameters Tables in RichFaces

RichFaces provides eight predefined skin parameters (skins) at the simplest level of common customization:

- DEFAULT
- plain
- emeraldTown
- blueSky
- wine
- japanCherry
- ruby
- classic
- deepMarine

To plug one in, it's necessary to specify a skin name in the "org.richfaces.SKIN" context-param.

Here is an example of a table with values for one of the main skins, "blueSky".

Colors

Parameter name | Default value
--- | ---
headerBackgroundColor | #BED6F8
headerGradientColor | #F2F7FF
headTextColor | #000000
headerWeightFont | bold
generalBackgroundColor | #FFFFFF
generalTextColor | #000000
generalSizeFont | 11px
generalFamilyFont | Arial, Verdana, sans-serif
controlTextColor | #000000
controlBackgroundColor | #ffffff
additionalBackgroundColor | #ECF4FE
shadowBackgroundColor | #000000
shadowOpacity | 1
panelBorderColor | #BED6F8
subBorderColor | #ffffff
tabBackgroundColor | #C6DEFF
tabDisabledTextColor | #8DB7F3
trimColor | #D6E6FB
tipBackgroundColor | #FAE6B0
tipBorderColor | #E5973E
selectControlColor | #E79A00
generalLinkColor | #0078D0
hoverLinkColor | #0090FF
visitedLinkColor | #0090FF

Fonts

Parameter name | Default value
--- | ---
headerSizeFont | 11px
headerFamilyFont | Arial, Verdana, sans-serif
tabSizeFont | 11px
tabFamilyFont | Arial, Verdana, sans-serif
buttonSizeFont | 11px
buttonFamilyFont | Arial, Verdana, sans-serif
tableBackgroundColor | #FFFFFF
tableFooterBackgroundColor | #cccccc
tableSubfooterBackgroundColor | #f1f1f1
tableBorderColor | #C0C0C0

Skin "plain" was added from 3.0.2 version. It doesn't have any parameters. It's necessary for embedding RichFaces components into existing projecst which have its own styles.

To get detailed information on particular parameter possibilities, see the chapter where each component has skin parameters described corresponding to its elements.

### Creating and Using Your Own Skin File

In order to create your own skin file, do the following:

- Create a file and define in it skin constants which are used by style classes (see section "Skin Parameters Tables in RichFaces"). The name of skin file should correspond to the following format: <name>.skin.properties. As an example of such file you can see RichFaces predefined skin parameters (skins): blueSky, classic, deepMarine, etc. These files are located in the richfaces-impl-xxxxx.jar inside the /META-INF/skins folder.

- Add a skin definition <contex-param> to the web.xml of your application. An example is placed below:

  Example:

      ...
          <context-param>
              <param-name>org.richfaces.SKIN</param-name>
              <param-value>name</param-value>
          </context-param>
      ...

- Put your <name>.skin.properties file in one of the following classpath elements: META-INF/skins/ or classpath folder (e.g. WEB-INF/classes).

### Built-in skinnability in RichFaces

RichFaces gives an opportunity to incorporate skinnability into UI design. With this framework you can easily use named skin parameters in properties files to control the appearance of the skins that are applied consistently to a whole set of components. You can look at examples of predefined skins at:

- http://livedemo.exadel.com/richfaces-demo/

You may simply control the look-and-feel of your application by using the skinnability service of the RichFaces framework. With the means of this service you can define the same style for rendering standard JSF components and custom JSF components built with the help of RichFaces.

To find out more on skinnability possibilities, follow these steps:

- Create a custom render kit and register it in the faces-config.xml like this:

      <render-kit>
              <render-kit-id>NEW_SKIN</render-kit-id>
              <render-kit-class>
                  org.ajax4jsf.framework.renderer.ChameleonRenderKitImpl
              </render-kit-class>
      </render-kit>

- Then you need to create and register custom renderers for the component based on the look-and-feel predefined variables:

      <renderer>
              <component-family>javax.faces.Command</component-family>
              <renderer-type>javax.faces.Link</renderer-type>
              <renderer-class>
                 newskin.HtmlCommandLinkRenderer
              </renderer-class>
      </renderer>

- Finally, you need to place a properties file with skin parameters into the class path root. There are two requirements for the properties file:
  - The file must be named <skinName> .skin.properties, in this case, it would be called `newskin.skin.properties`.
  - The first line in this file should be render.kit= <render-kit-id>, in this case, it would be called render.kit=NEW_SKIN.

Extra information on custom renderers creation can be found at:

- http://java.sun.com/javaee/javaserverfaces/reference/docs/index.html