The Twister workflow engine is one possible engine to use for the class project. It has the following advantages:
Twister is Struts-based so it also serves as yet another example of Struts code.
The following notes are based on my experiences installing Twister and getting it to run. These are not a standalone set of installation instructions. They are annotations to the Twister Installation Guide. The Guide is pretty clear. These notes correct a few mistakes and emphasize steps that I found critical to getting a working workflow engine.
These notes are specific to Windows -- someone with Unix should send me the corresponding Unix points.
If you haven't downloaded Ant before, do so now.
After installing Ant, be sure to
ANT_HOMEto be the directory where you installed Ant, and
%ANT_HOME%\binto the user environment variable
Download the source from the Twister home page.
Extract the files anywhere you want. I put mine in my Java directory. Do not put them in your Tomcat directory.
Follow the Installation Guide here. You can skip the section on Hibernate unless you want to substitute some other database for the built-in HSQL.
Note: You have to be online for the
ant db-createstep to work. If you are not online, the XML parser will fail because it can't find the DTD it needs. [This is a common problem with XML-based systems. It can be fixed by including local copies of the DTD in the installed setup.]
Xindice is an XML database system.
The Installation Guide says to look in the Twister
Xindice.war. This is a typo. You'll find
Xindice.warto your Tomcat
This has several steps, mostly just copying things.
ContentXML element in the Installation Guide and insert it as directed in your Tomcat
conf/server.xmlfile. This is necessary to define the admin user. You should insert this element just before the
server.xml, or, if you have a
<DefaultContext>element, just before that. Save and close this file.
twister-ws.warfrom the Twister
wardirectory to your Tomcat
webappsdirectory. DO NOT START TOMCAT YET.
hsql-db-1.7.1.jarfrom the Twister
libdirectory into your Tomcat
confdirectory into your Tomcat's
The Installation Guide gives an incorrect demo. The correct demo is in the User Guide. It steps you through:
Go through this demo -- read each step carefully -- and make sure it works all the way to the end.
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