/** INTERNAL: Acquires a special historical session for reading objects as of a past time. */ public org.eclipse.persistence.sessions.Session acquireHistoricalSession(AsOfClause clause) throws ValidationException { if (isServerSessionBroker()) { throw ValidationException.cannotAcquireHistoricalSession(); } // ? logMessage("acquire_client_session_broker", (Object[])null); SessionBroker historicalBroker = copySessionBroker(); String sessionName; AbstractSession session; Iterator names = this.getSessionsByName().keySet().iterator(); while (names.hasNext()) { sessionName = (String) names.next(); session = getSessionForName(sessionName); historicalBroker.registerSession(sessionName, session.acquireHistoricalSession(clause)); } return historicalBroker; }