Creates a ValueExtractor which extracts values from Monitors matching the specified tag.
Creates a ValueExtractor which extracts values from Monitors matching the specified tag. If the monitor is a CompositeMonitor and one of its sub-monitors matches the tag then the value of this monitor is returned. If the monitor is not a CompositeMonitor, then if the value of the monitor itself matches the tag, the value of the monitor is returned
Creates a ValueExtractor which returns the value of the specified monitor
Creates a ValueExtractor which returns the value of the tag with the specified key from the monitor