xaresourcemngr.java

一个类似于openJMS分布在ObjectWeb之下的JMS消息中间件。

   * @exception XAException  If the specified transaction is in an
   *                         incompatible state with the commit request,
   *                         or if the request fails.
   */
  synchronized void commit(Xid xid) 
    throws XAException {

    if (JoramTracing.dbgClient.isLoggable(BasicLevel.DEBUG))
      JoramTracing.dbgClient.log(BasicLevel.DEBUG,
                                 "--- "
                                 + this
                                 + ": commit(" + xid + ")"); 

    try {
      if (getStatus(xid) != PREPARED)
        throw new XAException("Can't commit non prepared transaction.");

      XAContext xaC = (XAContext) transactions.get(xid);

      if (JoramTracing.dbgClient.isLoggable(BasicLevel.DEBUG))
        JoramTracing.dbgClient.log(BasicLevel.DEBUG,
                                   "--- "
                                   + this
                                   + ": commits transaction "
                                   + xid.toString()); 

      cnx.syncRequest(new XACnxCommit(xid.getBranchQualifier(),
                                       xid.getFormatId(),
                                       xid.getGlobalTransactionId())); 

      transactions.remove(xid);
      Session session = (Session) sessionTable.get(xid);
      if (session != null)
        session.setTransacted(false);

    } catch (JMSException exc) {
      setStatus(xid, ROLLBACK_ONLY);
      throw new XAException("Commit request failed: " + exc);
    } catch (XAException exc) {
      setStatus(xid, ROLLBACK_ONLY);
      throw exc;
    }
  }

  /** 
   * Notifies the RM that a transaction is rolled back.
   *
   * @exception XAException  If the specified transaction is in an
   *                         incompatible state with the rollback request,
   *                         or if the request fails.
   */
  synchronized void rollback(Xid xid)
    throws XAException {

    if (JoramTracing.dbgClient.isLoggable(BasicLevel.DEBUG))
      JoramTracing.dbgClient.log(BasicLevel.DEBUG,
                                 "--- "
                                 + this
                                 + ": rollback(" + xid + ")");

    try {
      XAContext xaC = (XAContext) transactions.get(xid);

      if (xaC == null)
        throw new XAException("Unknown transaction.");

      if (JoramTracing.dbgClient.isLoggable(BasicLevel.DEBUG))
        JoramTracing.dbgClient.log(BasicLevel.DEBUG,
                                   "--- "
                                   + this
                                   + ": rolls back transaction "
                                   + xid.toString()); 

      Enumeration targets; 
      String target;
      MessageAcks acks;

      XACnxRollback rollbackRequest;
  
      targets = xaC.deliveries.keys();
  
      rollbackRequest = new XACnxRollback(xid.getBranchQualifier(),
                                           xid.getFormatId(),
                                           xid.getGlobalTransactionId());

      while (targets.hasMoreElements()) {
        target = (String) targets.nextElement();
        acks = (MessageAcks) xaC.deliveries.remove(target);
        rollbackRequest.add(target, acks.getIds(), acks.getQueueMode());
      }

      // Sending to the proxy:
      cnx.syncRequest(rollbackRequest);

      transactions.remove(xid);
      Session session = (Session) sessionTable.get(xid);
      if (session != null) {
        session.setTransacted(false);
        sessionTable.remove(xid);
      }
    } catch (JMSException exc) {
      setStatus(xid, ROLLBACK_ONLY);
      throw new XAException("Rollback request failed: " + exc);
    } catch (XAException exc) {
      setStatus(xid, ROLLBACK_ONLY);
      throw exc;
    }
  }

  /** 
   * Notifies the RM to recover the prepared transactions.
   *
   * @exception XAException  If the specified flag is invalid, or if the
   *                         request fails.
   */
  synchronized Xid[] recover(int flag) throws XAException
  {
    if (JoramTracing.dbgClient.isLoggable(BasicLevel.DEBUG))
      JoramTracing.dbgClient.log(BasicLevel.DEBUG,
                                 "--- "
                                 + this
                                 + ": recovers transactions.");

    if (flag == XAResource.TMSTARTRSCAN || flag == XAResource.TMENDRSCAN)
      throw new XAException("Non supported recovery flag: " + flag);

    try {
      XACnxRecoverReply reply =
        (XACnxRecoverReply) cnx.syncRequest(new XACnxRecoverRequest());

      Xid[] xids = new Xid[reply.getSize()];

      for (int i = 0; i < reply.getSize(); i++) {
        xids[i] = new XidImpl(reply.getBranchQualifier(i),
                              reply.getFormatId(i),
                              reply.getGlobalTransactionId(i));
      }
      return xids;
    }
    catch (Exception exc) {
      throw new XAException("Recovery request failed: " + exc.getMessage());
    }
  }

  /** 
   * Sets the status of a transaction.
   *
   * @exception XAException  If the transaction is unknown.
   */
  private void setStatus(Xid xid, int status) throws XAException
  {
    XAContext xac = (XAContext) transactions.get(xid);

    if (xac == null)
      throw new XAException("Unknown transaction.");

    xac.status = status;
  }

  /** 
   * Gets the status of a transaction.
   *
   * @exception XAException  If the transaction is unknown.
   */
  private int getStatus(Xid xid) throws XAException
  {
    XAContext xac = (XAContext) transactions.get(xid);

    if (xac == null)
      throw new XAException("Unknown transaction.");

    return xac.status;
  }

  /** Resource managers are equal if they belong to the same connection. */
  public boolean equals(Object o) {
    if (! (o instanceof XAResourceMngr))
      return false;

    XAResourceMngr other = (XAResourceMngr) o;

    if (JoramTracing.dbgClient.isLoggable(BasicLevel.DEBUG))
      JoramTracing.dbgClient.log(BasicLevel.DEBUG,
                                 this + ": equals other = " + other.cnx + 
                                 ", this.cnx = " + cnx +
                                 ", equals = " + cnx.equals(other.cnx));
    
    return cnx.equals(other.cnx);
  }
}

/**
 * Utility class holding a resource's state during transaction progress.
 */
class XAContext
{
  /** The transaction status. */
  int status;
  /**
   * Table holding the <code>ProducerMessages</code> produced in the
   * transaction.
   * <p>
   * <b>Key:</b> destination name<br>
   * <b>Object:</b> <code>ProducerMessages</code>
   */
  Hashtable sendings;
  /** 
   * Table holding the identifiers of the messages delivered per
   * destination or subscription, in the transaction.
   * <p>
   * <b>Key:</b> destination or subscription name<br>
   * <b>Object:</b> corresponding <code>MessageAcks</code> instance
   */
  Hashtable deliveries;


  /**
   * Constructs an <code>XAContext</code> instance.
   */
  XAContext()
  {
    sendings = new Hashtable();
    deliveries = new Hashtable();
  }


  /**
   * Adds new sendings performed by the resumed transaction.
   */
  void addSendings(Hashtable newSendings)
  {
    String newDest;
    ProducerMessages newPM;
    ProducerMessages storedPM;
    Vector msgs;

    // Browsing the destinations for which messages have been produced:
    Enumeration newDests = newSendings.keys();
    while (newDests.hasMoreElements()) {
      newDest = (String) newDests.nextElement();
      newPM = (ProducerMessages) newSendings.remove(newDest);
      storedPM = (ProducerMessages) sendings.get(newDest);
      // If messages haven't already been produced for this destination,
      // storing the new ProducerMessages object:
      if (storedPM == null)
        sendings.put(newDest, newPM);
      // Else, adding the newly produced messages to the existing
      // ProducerMessages:
      else {
        msgs = newPM.getMessages();
        for (int i = 0; i < msgs.size(); i++)
          storedPM.addMessage((org.objectweb.joram.shared.messages.Message)
                              msgs.get(i));
      }
    }
  }

  /**
   * Adds new deliveries occured within the resumed transaction.
   */
  void addDeliveries(Hashtable newDeliveries)
  {
    String newName;
    MessageAcks newAcks;
    MessageAcks storedAcks;

    // Browsing the destinations or subscriptions to which messages will have
    // to be acknowledged:
    Enumeration newNames = newDeliveries.keys();
    while (newNames.hasMoreElements()) {
      newName = (String) newNames.nextElement();
      newAcks = (MessageAcks) newDeliveries.remove(newName);
      storedAcks = (MessageAcks) deliveries.get(newName);
      // If there are no messages to acknowledge for this destination or 
      // subscription, storing the new vector:
      if (storedAcks == null)
        deliveries.put(newName, newAcks);
      // Else, adding the new ids to the stored ones:
      else
        storedAcks.addIds(newAcks.getIds());
    }
  }
}