CSc 667/867CSc 667/867Java Web Start / JNLPJava Web Start / JNLP

RSSRSS

CSc 667/867CSc 667/867Java Web Start / JNLPJava Web Start / JNLP

RSSRSS

Deploying Software with JNLP and Java Web

Start • Delivering client-side Java technology-based progr

ams has recently been a daunting task. Browser differences -- both in versions of the Java Runtime Environment (JRE) and security architecture -- have caused many developers to abandon rich client-side solutions in favor of using Java technology on the server, with JavaServer Pages (JSPTM) and servlets. But now that Java Web Start -- and the underlying Java Network Launch Protocol (JNLP) -- are a standard part of the Java 2 platform (as of version 1.4), it's far easier to deploy cross-platform, client-side systems.

Java Web Start • a mechanism for program delivery through a

standard Web server. Typically initiated through the browser, these programs are deployed to the client and executed outside the scope of the browser.

• Once deployed, the programs do not need to be downloaded again, and they can automatically download updates on startup without requiring the user to go through the whole installation process again.

• They continue to run within a restricted container, or sandbox. Since Java Web Start runs on top of the Java 2 platform, you also have access to the underlying security architecture.

How to launch JWS at your browser?

• download Web Start for your platform. Java Web Start itself is only about 1 MB. However, it requires the Java Runtime Environment (JRE), so if a you (or a user) don't have a JRE, the download size increases accordingly, to just under 6 MB on Microsoft Windows platforms.

Tutorials & Good resources

• From Setup Java Web Start to Jar signing– http://www.mobilefish.com/developer/java

webstart/javawebstart.html• Deploying Software with JNLP and Java

Web Start– http://java.sun.com/developer/technicalAr

ticles/Programming/jnlp/

Steps to set up a JWS• The client machine requires support for the Ja

va Runtime Environment (JRE), version 1.2.2 or higher.

• The Web server where the application is deployed must be configured with support for a new MIME type. – application/x-java-jnlp-file jnlp

RSS or RSS Feed• a Web site will make a feed, or channel,

available, just like any other file or resource on the server. Once a feed is available, computers can regularly fetch the file to get the most recent items on the list. Most often, people will do this with an aggregator, a program that manages a number of lists and presents them in a single interface.

RSS - What is all the fuss about?

What is RSS Good For?

• RSS can deliver current information from the Internet in our areas of expertise or interest.

– RSS comes close to fulfilling the promise of a custom newspaper or magazine that is delivered to our desktop.

– Some RSS feeds are updated hourly (Associated Press and BBC news), some RSS feeds are updated daily, and others are updated weekly or irregularly. RSS reduces my web surfing time and gives me more reading time.

• RSS can provide content for websites and blogs.

• RSS can bring additional traffic to a website or blog.

Purpose of RSS• Instant information

– Information updated in realtime• Single source

– All information aggregated in a signle location, or personalization

• Rapid scanning– Feed readers highlight unread headlines

• Categorizing– Information can be categorized by theme

Make RSS Feeds (RSS Tags)• <channel></channel> : Root Element• Required children elements

– <title>, <link>, <description>• Optional children elements

– <pubDate>, <lastBuildDate>, <language>, <copyright>, <webmaster> <managingEditor>, <category>, <generator>, etc

<channel> <title> Make RSS Feeds </title><description> Details RSS feed creation in a step by step fashion </description><link> http://www.make-rss-feeds.com </link> <pubDate> Aug, 22 2004 00:12:30 EST </pubDate><lastBuildDate> Aug, 22 2004 00:12:30 EST </lastBuildDate><language> en-us </language><copyright> Copyright 2004, NotePage, Inc.</copyright> <webMaster> webmaster@notepage.net </webMaster><managingEditor> webmaster@notepage.net </managingEditor> <category> newspapers </category> <generator> feedforall </generator> <ttl> 120 </ttl> <docs> http://blogs.law.harvard.edu/tech </docs> </channel>

RSS Tags• Image <image> is a child element of <channe

l> and can have children elements as below:– title, description, url, width, height, link (a hyper lin

k when the image is clicked)

• Item <item> is a child element of <channel> and can have children elements as below:– title, description, link, pubDate, category,

Creating RSS Feeds1. Create a feed (filling the tags)2. Determine Content

RSS feed can be used an number of ways. The idea is for a feed to contain content that will be updated on a regular basis.

3. Enter Data in Main Fields – The important fields are:– Channel - title, description & links

Item - title, description & links– You may enter data either using server side program or

manually.

5. Submit Feed (xml file) to RSS search engines and directories (so people find it well)

6. Publish the feed on your web site

Behind the scene• You may use Bloglines or my Yahoo! To subsc

ribe a specific RSS for your interesting subject.

• The RSS pub updates “something.xml” at its web site.

• My Yahoo! Or Bloglines will periodically check that xml file to see if it has been updated.