How do you get the previous/current value of a tag using context.getTagManager().subscribeAsync ?
I see com.inductiveautomation.ignition.common.util.FilteredTagChangeListener.FilteredTagChangeEvent that looks like it has what I want but haven’t been able to implement it.
What have you tried doing so far?
It looks like you can subclass
FilteredTagChangeListener and provide it as your listener to
How do you pass in the 2nd parameter? java.util.EnumSet<FilteredTagChangeListener.TagChangeType> allowedChanges
Just build an
There’s also nothing special about this listener. It’s just a listener that happens to remember the last value for any given tag path and deliver that in its own event type via the
onFilteredTagChange method you override. Plus some options for suppressing initial events and filtering certain changes. It’s used by the gateway tag change scripts.