62.6.1 Using Configuration Variables in XML

The builtin XML parser offers a special mechanism—configuration variables—to reuse and customize content at runtime.

A configuration variable is an RTI-specific construct that you can use in the input XML documents to set placeholders for content that will be expanded at parsing time. Specify a variable as follows:

$(VAR_NAME)

where VAR_NAME is the name that identifies the variable. You can use configuration variables in your XML content as an attribute value and element text. For example:

<element attribute="$(VAR_ATTR)">my expanded $(VAR_TEXT)</element>

The possible ways a variable can be expanded are listed below in precedence order:

1. Process an environment variable such as the following:

export VAR_NAME=my_value

2. Process the <configuration_variables> section, which represents an unbounded list of variable name-value pairs. For example:

<configuration_variables>

    <value>

        <element>

            <name>VAR_NAME</name>

            <value>var_value</value>

        </element>

        ...

    </value>

</configuration_variables>

These two mechanisms can be used in combination or separately.