BPELUnit Date arithmetic

bpelunit.xml

<unit:condition>
    <unit:template><![CDATA[(
        ## Since XPath 1.0 does not support date manipulation functions,
        ## we rely on Velocity's DateTool to perform the arithmetic involved.
        ##
        ## The substring(..) calls build a number from an ISO 8601 string.
        ## The resulting number is subtracted from the current date/time built using Velocity.
        ##
        ## The result of the operation is the duration between the two dates, in seconds.
        (
            number('$date.get("yMMddHHmmss")') -
            number(
                concat(
                    substring(//xpath/expression, 1, 4),
                    substring(//xpath/expression, 6, 2),
                    substring(//xpath/expression, 9, 2),
                    substring(//xpath/expression, 12, 2),
                    substring(//xpath/expression, 15, 2),
                    substring(//xpath/expression, 18, 2)
                )
            )
        ) < (30 * 60)
    )]]></unit:template>
    <unit:value>true()</unit:value>
</unit:condition>