Introducing conf2admin
conf2admin is a utility that processes a config.xml and produces output in the form of a scripting language. The current implementation includes support for weblogic.Admin, but Ant and WLShell are planned. The primary features of conf2admin are:

The BEA WebLogic Server domain configuration is an XML format file that describes the configuration for servers, clusters, and applications to name a few. The conf2admin utility works by executing an XSLT transformation against the config.xml document, and has XSL templates that produce the commands necessary for creating and setting values on WebLogic Server domain entities.

Figure 1 illustrates the general concept of conf2admin. Before we continue, let's take a brief look at the core technology behind conf2admin, the Extensible Stylesheet Language Transformations or XSLT.

 

XSLT
XSLT is an XML-based transformation language that works by matching templates against markup-like elements and attributes in an XML document. The templates in conf2admin match against elements in the BEA WebLogic Server domain configuration. The output from these templates is the script code that you will execute using weblogic.Admin or some other script interpreter. The following code snippet shows what a template looks like.

<xsl:template match="//Server">

<!—specify contents of template here ‡

</xsl:template>

XSLT is a good choice for working with an XML-based configuration. We can get document parsing for free from the XML parser, and a parser for the templates. Writing an XSLT template is pretty straightforward. I won't cover the XSLT specification in depth, but will focus on the sections of the stylesheet relevant to the code generation.

Applying conf2admin to Medrec
We'll take the conf2admin utility and run it against the WebLogic Server MedRec samples domain configuration. The MedRec sample ships with BEA WebLogic Server and includes a variety of WebLogic Server resources. Depending on which release of BEA WebLogic Server you have, your MedRec domain configuration might be slightly different. We'll run the utility and focus on the MedRecServer and JDBCConnectionPool resources that will be generated. Those resources are represented by entries in the domain configuration that look like Listing 2.

When you run the conf2admin utility against the MedRec config.xml, the resulting file will be filled with many lines of generated code; the two snippets for our example deal with the server and the JDBCConnectionPool (see Listing 3)

From the output you can see that a command for CREATE was generated that will create the server. There were also four SET commands created, each representing the set for an attribute on that Server. Listing 4 lists similar results for the JDBCConnectionPool.

The conf2admin utility matches against elements in the configuration, in this case the server and JDBCConnectionPool elements, and instantiates the template for emitting CREATE commands. The stylesheet does not name the individual elements it looks for; it merely matches against whatever elements it finds. Next, within the template that emits the CREATE commands, conf2admin begins processing attributes and emitting commands to SET properties on the newly created server or JDBCConnectionPool entities. This flow of processing continues until the entire document has been processed.

The conf2admin utility will also emit some comment blocks, which indicate the source location in the config.xml that the generated code came from. So in the example of the MedRecServer, the comment block looks like this:

#================================================
#==
#== Creating MBean of type Server
#==
#== Origin: /[1]/Domain[1]/Server[1]
#==
#================================================

The origin comment indicates the location in the document expressed as an XPath expression. The numbers in brackets are the indices of the element since in some cases there can be several of a particular type.

Once the output is generated, you can use that file as input into the weblogic.Admin interpreter in batch mode. The documentation for conf2admin describes how to configure it to generate commands for stand-alone interpretation of script commands. The default is to generate commands to be used in batch mode of weblogic.Admin.

Summary
In this article I looked at the scripting languages that are available for BEA WebLogic Server and how you can use code generation to enable quick creation of management scripts. While seemingly powerful, there are some limitations to using XSLT to generate code. It does not include a friendly interface for looping to reprocess parts; instead, you must recursively call a template until you are finished processing. There is also no real concept of flow control within a template.

Links
The following links may provide you with more details about the technologies and concepts discussed here.