Last week I was in Amsterdam (in the very nice Hotel Krasnapolsky) to give a course at the Sofware AG 9th European Training week about 'Developing XML Applications withthe Open Source Technology'.

You will find here a summary of the course.

1. Open Source

If you don't know what is open source :

• 1Minute Open Source (coming soon)
• http://www.free-soft.org/

There are a lot of open source projects on the internet. If you have alook at http://www.sourceforge.org you will see that this open sourcerepository counts 35,241 hosted projects and 369,695 registered users. The biggest open source projects include Operating systems (Linux, freeBSD,openBSD, freeBSD), programming languages (C, C++, php, Perl, Python...), WebBrowsers (Netscape 6), Office Open Suites (OpenOffice) and servers (Apache -63% of webservers worldwide !! , MySQL, PostgreSQL...).

I personnally use a lot of open source on my machine for my everyday use:

• postnuke, MySQL and PHP for my website
• Amaya to write my websites articles -offline - in XHTML
• Tomcat and Apache for my presales demos
• NetBeans as a Java IDE
• JEdit as a text editor

You can find a lot of Open Source stuff that can be usefull and give youreal productivity in your everyday work.

2. Open Source and XML

In the XML Arena, we use a lot of OpenSource. Here is a small list of XMLtools available in open source :

• XML EDI : mec-eagle - http://www.mec-eagle.org compatible with SAP IDocs, RosettaNet,... (I have never tested it)
• XML EDI : HL7API - http://hl7api.sourceforge.net/ for converting HL7 messages to XML
• XML Workflow : The Open For Business Project - http://www.ofbiz.org
• XML Transformation : Xalan - XSLT stylesheet processors, in Java and C++, http://xml.apache.org/
• XML Transformation : SAXON - The XSLT Processor http://saxon.sourceforge.net/ (See 'About Open Source by Michael Kay ? Software AG')
• XML SOAP Apache - http://xml.apache.org/soap/
• XML SOAP UDDI - http://soapuddi.sourceforge.net/
• XML Portals : Jetspeed - http://java.apache.org/jetspeed/
• XML Publishing : Cocoon - http://xml.apache.org/cocoon/
• XML Repositories : http://exist-db.org/
• XML Repositories : http://www.dbxml.com/
• XML aware IDE : Netbeans - http://www.netbeans.org/
• XML Authoring : Amaya for XHTML - http://www.w3.org/Amaya/
• XML Authoring : ABIWord - http://www.abiword.org/
• XML Authoring : OpenOffice - http://www.openoffice.org/ claim they can save in XML.

3. Software AG and Open Source

At Sofware AG we use the open source within our projects and in theenabling services of Tamino

Within our projects :

• Parsers and Transformers (Xalan, Xerces)
• EJB countainer : JBoss - http://www.jboss.org/
• WebServers : Tomcat, Apache
• ...

For Tamino :

• Tomcat (XApplication and WebDAV Server)
• Parsers and Transformers (JDOM, Xalan, Xerces, ... ) into a lot of tools (Passthru servlet, X-Plorer,...)
• Perl as a scripting language (Load utilities)
• The SOAP Toolkits of Apache (XApplication WebServices)

4. Conclusions

Why Would I buy Commercial Sofware if I can have all this for free ? Intheory it?s ok, what about the practice ?

We can find a lot of usefull software (for XML as well)

• If we search
• If we can understand what it does

We must always evaluate the open source; is it :

• Maintained (Who are the people behind it ?) ?
• Reliable, Performant ?
• Easy to use or learn ?
• Compatible with other open source products ?
• Open, Standard based ?

So, Time is money. If you have the time to find and evaluate the opensource you will earn the money of not purchasing the software.

My feeling is that it's ok to use Open Source if

1. you respect the Open-ClosedPrinciple = Don't change the source (unless you participate to theproject) !!

2. You have the feeling that you will be able to support your application-built with open source - for a long time (the complete software lifecycle). This is probably reasonable for big projects like Linux, but maybe not for smaller projects. Be aware of the people behind the scenes of the open source communities.