Understanding configuration definitions and schemas

Configuration definitions are XML documents that contain all the configuration items and their values, as defined during the development process.

These definitions are packaged in the application archive. They can be modified during the application assembly phase and repackaged with the application. At deployment, the configuration definitions are used to establish the initial configuration in the configuration repository. They can also be used as the vehicle for replicating existing configuration.

Configuration definitions can contain both static and dynamic configuration. For an operational application, the Management Console allows administrators to change both dynamic configuration items and static configuration items, but will give warnings before changing static configuration items.

The configuration definition distributed with the application is considered to contain the factory defaults for the configuration. Any changes to this configuration can potentially be overwritten by upgrades to subsequent versions of the application. If you want to change your configuration while retaining factory defaults, you should do so from the Management Console after the application (and its configuration) is deployed.

The configuration is structured hierarchically and is therefore well-suited to be represented in an XML document. Configuration consists of nodes and items. Nodes are containers for other nodes and items while items represent the actual configurable values. In the XML document the nodes correspond to XML entities while the items correspond to entity attributes.

The root node of the application XML document is the application name in which any spaces have been replaced with hyphens ("-"). If the application consists of modules (for example, an enterprise application that contains EJB and Web modules), the root's immediate child nodes correspond to those modules. If the name of root node of a module's XML documents are same, then all child nodes are put under the same root node. The name of the root node of all modules is IBM®. The rest of the nodes are used to structure the configuration logically according to the functional areas within the application or within each module.

The following is an example of application configuration XML:

<?xmlversion="1.0"?>
<MDMMergedConfiguration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                        xsi:noNamespaceSchemaLocation="dwl-config.xsd">
  <IBM>
    <DWLCommonServices>
      <Notifications enabled="false" defaultLanguage="100"/>
      <PerformanceTracking level="0"/>
      <Security enabled="false"/>
      <TAIL enabled="false" maxRecords="100"/>

      <Validation>
        <External enabled="true"/>
      </Validation>
      <XML useValidatingParser="true"/>
      <ExtensionFramework enabled="true"/>
      <RedundantUpdate enabled="false"/>
    </DWLCommonServices>

    <FinancialServices>
      <Contract>
        <Search maxResults="100"/>
      </Contract>
    </FinancialServices>

    <Party>
      <Search maxResults="100"/>

      <Standardizer>
        <Address className="com.dwl.tcrm.coreParty.component.TCRMAddressStandardizer"/>
        <Name className="com.dwl.tcrm.coreParty.component.TCRMPartyStandardizer"/>
      </Standardizer>
      <SuspectProcessing enabled="true">
        <AddParty returnSuspect="true"/>
      </SuspectProcessing>
    </Party>
  </IBM>
</MDMMergedConfiguration>

When the application consists of modules, the final configuration definition is compiled at deployment time by combining together all the configuration definitions, the dwl-config.xml files, found inside the modules into a master configuration definition.

The location of the configuration definitions in the packaged application depends on the managed application type:

• J2SE Application—There is only one configuration definition per application. The name of the XML document is dwl-config.xml and it can be found in the META-INF directory of the application JAR.
• Java EE Application—There is one configuration definition document for each EJB or Web module and one for the application. All configuration definitions are contained in XML documents named dwl-config.xml that are located in the META-INF directory of the EJB module JAR, Web module WAR, or enterprise application EAR. At deployment time, all the configuration definitions of the EJB and Web modules contained in an enterprise application are merged into the configuration definition found in the enterprise application EAR file. Items in the EAR's configuration definition override items in the module-specific definitions.

Each configuration definition has an XML schema associated with it. This schema is called the configuration definition schema and it is contained in a file named dwl-config.xsd that is packaged together with the corresponding configuration definition document in the EJB, web or application archive. The application's schema references the EJB and Web modules schemas. The schema serves as the metadata to validate the configuration. It can provide information about the cardinalities of the configuration items relative to each other, types of data, and possible values for enumerated items. Configuration definition schemas are deployed in the Configuration and Management database at the same time that the application configuration is deployed.

Configuration definition schemas of InfoSphere® MDM modules use only local element to avoid name conflict while merging modules' configuration schemas. Use the same method for configuring the definition schemas of client modules. Similar to the way in which the configuration definitions of the modules are compiled into a master configuration definition for the application, the configuration definition schemas for the modules (dwl-config.xsd files) are combined into a master configuration definition schema for the application.