It is extremely important to minimise the references in this class, because Lucene keeps a global cache of these
objects in a WeakHashMap. If this class has lots of outgoing references, then the retained size increases if this
class is held onto, and also the risk of a circular reference back to the key of the WeakHashMap increases, which
means it can't be garbage collected.
Get the constant that this field is indexed with.
Check if the field is always part of an issues data. This should only return false in the case of a
custom field where the value does not have to be set for each issue.
- true if this mapper will always be part of an issues data