[OJB-135] Can't get access to underlying DBCP connection for Oracle CLOBs greater than 4000 characters

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.0.4
• Component/s: RDBMS platform-specific support
• Assignee: Armin Waibel
• Reporter: Eric Westfall
• Created: 24/Aug/07 22:03
• Updated: 08/Apr/08 14:56

Description

I might be missing something here but whenever PlatformOracle9iImpl is attempting to unwrap the underlying connection a DBCP pooled connection (pooled via Tomcat 5.5), it appears to be getting an IllegalAccessException since the class which is holding the wrapped connection is a private inner class (org.apache.commons.dbcp.dbcp.PoolingDriver.PoolGuardConnectionWrapper) so the genericUnwrap is returning null. This still occurs even if I set accessToUnderlyingConnectionAllowed to true on the DBCP data source factory.

Spring has a class which implements this functionality called the CommonsDbcpNativeJdbcExtractor which deals with the successfully by falling back to retrieving the underlying connection from the Database metadata. If I patch PlatformOracle9iImpl accordingly, this works great. Here is the implementation of unwrapConnection which works successfully for me (note, code below is essentially copied from the aforementioned spring code):

/**

• Return an OracleConnection after trying to unwrap from known Connection wrappers.
• @param conn the connection to unwrap (if needed)
• @return OracleConnection or null if not able to unwrap
  */
  protected Connection unwrapConnection(Connection conn)
  {
  Object unwrapped = genericUnwrap(ORA_CONN_CLASS, conn, UNWRAP_CONN_METHOD_NAMES, UNWRAP_CONN_PARAM_TYPES);
  try {
  // We haven't received a different Connection, so we'll assume that there's
  // some additional proxying going on. Let's check whether we get something
  // different back from the DatabaseMetaData.getConnection() call.
  DatabaseMetaData metaData = conn.getMetaData();
  // The following check is only really there for mock Connections
  // which might not carry a DatabaseMetaData instance.
  if (metaData != null)
  Unknown macro: { Connection metaCon = metaData.getConnection(); if (metaCon != conn) { // We've received a different Connection there: // Let's retry the native extraction process with it. unwrapped = genericUnwrap(ORA_CONN_CLASS, metaCon, UNWRAP_CONN_METHOD_NAMES, UNWRAP_CONN_PARAM_TYPES); } }

  } catch (SQLException e)

  Unknown macro: { if (logger.isDebugEnabled()) { logger.debug("Failed attempting to unwrap connection via database metadata.", e); } }

  if (unwrapped == null)

  Unknown macro: { // mkalen}

  return (Connection) unwrapped;
  }