Describe the issue
Boolean attributes in a configuration have to conform to the regex (true|false)|($\{[^\}]+\}), except for the active attribute. This makes it so that you can't use an ! before a property reference to negate it. To me, this makes no sense and it also makes it less readable and uglier and more complicated to create flexible configurations. I would advice treating all boolean attributes the same way as the active attribute.

Reporter
Lenard

Configuration
This problem causes needles clutter in configurations like:

<Param name="inverted.boolean" value="true" active="!${original.boolean}"/>
<Param name="inverted.boolean" value="false" active="${original.boolean}"/>

Or like this when a sender needs to be either synchronous or not.

<SenderPipe name="SenderPipe" active="${synchronous.boolean}">
      <IbisLocalSender javaListener="Listener"/>
</SenderPipe>

<SenderPipe name="SenderPipe" active="!${synchronous.boolean}">
      <IbisLocalSender javaListener="Listener" synchronous="false"/>
</SenderPipe>