The variable substitution engine operates on any text-based input source in the form of a String or Reader. In practice, however, only these entities are used as input sources:
Configuration-type resource files
Input to CLI commands that perform variable substitution on demand
Some of the component and plan attributes, such as the defaultInstallPath attribute of the <installSteps> element and the command attribute of the <execNative> step
See Chapter 2, Shared Schema Used by Components and Simple Plans, in N1 Grid Service Provisioning System 5.0 XML Schema Reference Guide, Chapter 3, Component Schema, in N1 Grid Service Provisioning System 5.0 XML Schema Reference Guide, and Chapter 4, Plan Schema, in N1 Grid Service Provisioning System 5.0 XML Schema Reference Guide.