title: How to convert an 18 Character String into a Unique ID?
body: <p>I have an 18 Character String that I need to convert into a unique long (in Java).
  A sample String would be: AAA2aNAAAAAAADnAAA</p>
  
  <p>My String is actually an Oracle ROWID, so it can be broken down if needs be, see:
  <a href="http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14220/datatype.htm#CNCPT713" rel="nofollow noreferrer">http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14220/datatype.htm#CNCPT713</a></p>
  
  <p>The long number generated, (1) Must be unique, as no two results can point to the same database row and (2) Must be reversible, so I can get the ROWID String back from the long?</p>
  
  <p>Any suggestions on an algorithm to use would be welcome.</p>
  
  <p>Oracle forum question on this from a few years ago : <a href="http://forums.oracle.com/forums/thread.jspa?messageID=1059740" rel="nofollow noreferrer">http://forums.oracle.com/forums/thread.jspa?messageID=1059740</a></p>
  
  <p>Ro</p>