[SOLVED] Creating a UUID from a string with no dashes

Creating a UUID from a string with no dashes

How would I create a java.util.UUID from a string with no dashes?

"5231b533ba17478798a3f2df37de2aD7" => #uuid "5231b533-ba17-4787-98a3-f2df37de2aD7"

Solution

Clojure's #uuid tagged literal is a pass-through to java.util.UUID/fromString. And, fromString splits it by the "-" and converts it into two Long values. (The format for UUID is standardized to 8-4-4-4-12 hex digits, but the "-" are really only there for validation and visual identification.)

The straight forward solution is to reinsert the "-" and use java.util.UUID/fromString.

(defn uuid-from-string [data]
  (java.util.UUID/fromString
   (clojure.string/replace data
                           #"(\w{8})(\w{4})(\w{4})(\w{4})(\w{12})"
                           "$1-$2-$3-$4-$5")))

If you want something without regular expressions, you can use a ByteBuffer and DatatypeConverter.

(defn uuid-from-string [data]
  (let [buffer (java.nio.ByteBuffer/wrap 
                 (javax.xml.bind.DatatypeConverter/parseHexBinary data))]
    (java.util.UUID. (.getLong buffer) (.getLong buffer))))