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How to Use the Rss Bar Component

Yutaka Yoshida
Status: In Early Access

RSS Bar Tag

The JavaServer Faces Rss Bar component generates necessary HTML tags and stylesheet for rendering the actual content of the RSS feed, which is obtained through AJAX request in the background. The tag library for the Rss Bar component can be accessed using the declaration <%@taglib prefix="ui" uri="http://java.sun.com/blueprints/ui" %>.

An example of the JSF Rss bar component's use is as follows:

     <ui:rssBar url="https://blueprints.dev.java.net/servlets/ProjectRSS?type=news"
         itemCount="4"
         title="News from BlurPrints"
         backgroundImage="default"
         fontSize="14"
         speed="3000"
         color="#00ffff"
         hoverColor="="#ff00ff">
     </ui:rssBar>

Above, the component tag name is rssBar, that has the following attributes added to a traditional HTML form component's attributes:

Attribute Description Required Default
url Specifies the URL of RSS feed Yes N/A
itemCount Specifies number of item in the RSS appear on the RSS Bar No All items
title Specifies the title of this RSS Bar No Title in the <channel>
backgroundImage Specifies if this RSS Bar needs the background image. Accepts only no or default No no
fontSize Specifies the font size of characters by pixel No 14
speed Specifies the speed of switching the items by millisecond No 2000
color Specifies the color of characters No #000033
hoverColor Specifies the color of characters when the mouse is over No #663300

Deployment Descriptor Configuration

Since XmlHttpRequest cannot retrieve the resource from the domain different from the original one, RssBar component has a http client to access the RSS feed. For the case when the proxy is required, the following configuration is necessary in web.xml deployment descriptor.


    <context-param>
        <param-name>proxyHost</param-name>
        <param-value>YOUR_PROXY_SERVER</param-value>
    </context-param>
    <context-param>
        <param-name>proxyPort</param-name>
        <param-value>YOUR_PROXY_PORT</param-value>
    </context-param>

The RssBar JSF component utilized Dojo and Apache Shale Remoting third party libraries to provide JavaScript AJAX functionality and the mechanism to access the dynamic resource. A com.sun.javaee.blueprints.components.ui.rss.RssFeedHandler instance is placed in the user's session once it is instantiated to cache the data from RSS Feed.


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