(prop :Map<String,Entry> entries (new Map))

(method :Void process [:Archive archive]
    (doFor e (entries.iterator)
        (processEntry archive e)))

(defNew [&prop :EntryChecker canProcessEntry
            &prop :EntryProcessor processEntry]
    [])

(prop &mut :Null<EntryProcessor> onRemoveEntry)

(method :Void checkEntryInOrOut [:Archive archive :Entry e]
    (if (canProcessEntry archive e)
            (dictSet entries e.id e)
        (when (entries.exists e.id)
            (entries.remove e.id)
            (when onRemoveEntry (onRemoveEntry archive e)))))

// TODO systems may need access to a UI or ArchiveController