[jboss-user] [JBoss Cache] - OptionalDataException when retrieving cached session

[Dan Kane]

Dan Kane [http://community.jboss.org/people/kanedk] created the discussion

"OptionalDataException when retrieving cached session"

To view the discussion, visit: http://community.jboss.org/message/591755#591755

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JBoss AS 4.2.2, JBoss Cache 1.4.1sp5

My appserver uses DB2 as a backend for JBoss Cache to persist sessions. I can kill the appserver, restart it and continue my session just fine - proving that it is storing and retrieving the session correctly.

However, I would like to write a standalone java app that accesses the session data in the JBOSSCACHE table, to inspect/verify it.


I can use a JDBCCacheLoader to connect to the DB. I create a Fqn and can use it to iterate through its children (the session records). I can even retrieve the byte[] that is supposedly the serialized form of the session object.

However, when I try to use an ObjectInputStream to readObject(), I always get an OptionalDataException, which makes no sense.

Code snippet:


 http://community.jboss.org/message/591755#591755 OptionalDataException when retrieving cached session
  JDBCCacheLoader cl = new JDBCCacheLoader();
      Properties props = new Properties();
      props.setProperty("cache.jdbc.driver", "com.ibm.db2.jcc.DB2Driver");
      props.setProperty("cache.jdbc.url", "jdbc:db2:-//host.domain.com");
      props.setProperty("cache.jdbc.user", "username");
      props.setProperty("cache.jdbc.password", "password");
      cl.setConfig(props);
      try
      {
        cl.create();
        String[] path = new String[] { "JSESSION", "localhost", "ROOT" };
        Fqn root = new Fqn(path);
        Set children = cl.getChildrenNames(root);
        int count = 5;
        for (Object c : children)
        {
          if (count == 0)
          {
            break;
          }
          count--;
          if (c instanceof String)
          {
            String cStr = root.toString() +"/"+ (String)c;
            Map m = cl.get(Fqn.fromString(cStr));
            Object obj = m.get(c);
            if (obj != null)
            {
              InputStream is = new ByteArrayInputStream((byte[])obj);
              try
              {
                ObjectInputStream ois = new ObjectInputStream(is);
                Object sess = ois.readObject(); // ***OptionalDataException***
                sess.hashCode();
              }
              catch (Exception ex)
              {
                //...
              }
            }
            else
            {
              //...
            }
          }
        }
      }
      catch (Exception ex)
      {
        Logger.getLogger(MainFrame.class.getName()).log(Level.ERROR, null, ex);
      }
 /code /code
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