dang.clj

(defn register-classed-indices [classes]
  (transaction-handler
    (afterCommit [_ data state] nil)
    (beforeCommit [_ data]
      (let [remnodes (into {} (map (fn [^Node node] [(.getId node) {}]) (.deletedNodes data)))
            rnodes (reduce (fn [props ^PropertyEntry removal] (update-in props [(.getId ^Node (.entity removal))] assoc (.key removal) (.previouslyCommitedValue removal))) remnodes (filter #(contains? remnodes (.getId ^Node (.entity ^PropertyEntry %))) (.removedNodeProperties data)))]
        (doseq [^PropertyEntry removal (.removedNodeProperties data)]
          (let [entity ^Node (.entity removal)
                key (.key removal)
                entity-id (.getId entity)
                class (if (contains? remnodes entity-id) ((rnodes entity-id) "__CLASS") (if (.hasProperty entity "__CLASS") (.getProperty entity "__CLASS")))]
            (when (and class (contains? (classes class) key))
              (.removeIndex *lucene* entity (str class "__" key))))))
      (doseq [^PropertyEntry assign (.assignedNodeProperties data)]
        (let [entity ^Node (.entity assign)
              key (.key assign)
              class (if (.hasProperty entity "__CLASS") (.getProperty entity "__CLASS"))
              previous-value (.previouslyCommitedValue assign)]
          (when (and class (contains? (classes class) key))
            (when previous-value
              (.removeIndex *lucene* entity (str class "__" key )))
            (.index *lucene* entity (str class "__" key) (.value assign))))))
    (afterRollback [_ data state] nil)))