gistfile1.txt

(defn parse-log-line
  [line]
  (next (re-matches #"(\[.+\]) ([^\s]+) \- (\w+ \w+ \w+)\s+(\w+) \-\- (.+)" line)))

(defn play
  []
  (let [line "[2011-09-15 11:28:58] dea - 1259 05ed 7573   INFO -- Max Memory set to 4.0G"]
    (loop [[x & xs] (parse-log-line line)]
      (if x
        (do
          (println x)
          (recur xs))))))

best I can come up with:

  (zipmap [:when :component :foo :level :message]
          (next
           (re-matches
            #"(\[.+\]) ([^\s]+) \- (\w+ \w+ \w+)\s+(\w+) \-\- (.+)"
            line)))