endpointrouter.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

    try {
      routedRoutes.put(r.dest, r);
      notifyAll();  // Wakeup those waiting for a route.
      return true;
    } catch (Exception e2) {
      // We failed, leave things as they are.
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("   failed with " + e2);
    }
    return false;
  }
  
  public synchronized void removeRoute(String pId) {
    
    try {
      routedRoutes.remove(pId);
    } catch (Exception e) {
    }
  }
  
  /**
   * @param msg The message which has just been recieved.
   * @param srcAddr The address from which this message was received.  This
   *                is addr is only one hop away.
   * @param dstAddr The destination for this message.  Should be one of this
   *                peer's addresses.
   *
   * @return The message, which should be delivered to a service on this peer.
   *         null if the message has been routed onward, or if the
   *         message should be dropped.
   */
  public void processIncomingMessage( Message msg,
  EndpointAddress srcAddr,
  EndpointAddress dstAddr	) {
    
    if (LOG.isEnabledFor(Priority.DEBUG))
      LOG.debug("processIncomingMessage starts");
    
    InputStream ip = null;
    
    String srcPeer = null;      // The originating peer
    String destPeer = null;     // The destination peer
    String lastHop = null;      // The last peer that routed this to us
    
    EndpointAddress origSrcAddr = null; // The origin endpointAddr (jxta:)
    EndpointAddress origDstAddr = null; // The dest endpointAddr   (jxta:)
    int nbOfHops = 0; // Nb of hops for the reverse route.
    
    EndpointRouterMessage routerMsg = null;
    MessageElement routerElement = msg.getElement(EndpointRouterMessage.Name);
    
    try {
      if (routerElement == null) {
        // The sender did not use this router
        if (LOG.isEnabledFor(Priority.DEBUG))
          LOG.debug("processIncomingMessage: no routing info");
        endpoint.demux(msg);
        return;
      }
      ip = routerElement.getStream();
      if (ip == null) {
        // The sender did not use this router
        if (LOG.isEnabledFor(Priority.DEBUG))
          LOG.debug("processIncomingMessage: invalid routing info");
        endpoint.demux(msg);
        return;
      }
      
      routerMsg = new EndpointRouterMessage(ip);
      
      try {
        nbOfHops = Integer.parseInt(routerMsg.getNbOfHops());
      } catch (Exception ez1) {
        nbOfHops = 0;
      }
      
      origSrcAddr =
      endpoint.newEndpointAddress(routerMsg.getSrcAddress());
      
      origDstAddr =
      endpoint.newEndpointAddress(routerMsg.getDestAddress());
      
      srcPeer = origSrcAddr.getProtocolName() + "://"
      + origSrcAddr.getProtocolAddress();
      destPeer = origDstAddr.getProtocolName() + "://"
      + origDstAddr.getProtocolAddress();
      lastHop = routerMsg.getLastHop();
      
      if (LOG.isEnabledFor(Priority.DEBUG)) { 
        LOG.debug(
          "Process Incoming : " +
          "\n\tsrcPeer= " + srcPeer +
          "\n\tdestPeer= " + destPeer + 
          "\n\tlastHop= " + ((null != lastHop) ? lastHop : "null") );
      }
      
      Vector g = routerMsg.getForwardGateways();
      if (g != null) {
        if (LOG.isEnabledFor(Priority.DEBUG))
          LOG.debug("    Forward Gateways:");
        for (int i = 0; i < g.size(); ++i) {
          try {
            if (LOG.isEnabledFor(Priority.DEBUG))
              LOG.debug("   [" + i + "] " + (String) g.elementAt(i));
          } catch (Exception ez1) {
            break;
          }
        }
      }
      g = routerMsg.getReverseGateways();
      if (g != null) {
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("    Reverse Gateways:");
        for (int i = 0; i < g.size(); ++i) {
          try {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("   [" + i + "] " + (String) g.elementAt(i));
          } catch (Exception ez1) {
            break;
          }
        }
      } else if ((nbOfHops >= 1) && (lastHop != null)) {
        // This is the case of a peer that has  not filled up the optional reverse gateway list.
        // Create one.
        Vector tmp = new Vector(1);
        tmp.add(lastHop);
        routerMsg.setReverseGateways(tmp);
      }
    } catch (Exception badHdr) {
      // Drop it, we do not even know the destination
      if (LOG.isEnabledFor(Priority.WARN)) LOG.warn("Bad routing header or bad message. Message dropped.");
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("exception: " + badHdr);
      return;
    }
    
    // Is this a loopback ?
    if ((srcPeer != null) && srcPeer.equals(localPeerAddr)) {
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processIncomingMessage: dropped loopback");
      return;
    }
    
    try {
      // Update routing information about that peer.
      // Do we already know about that peer ?
      
      if (lastHop != null) {
        // We're pretty sure we can talk to this peer directly
        // Remove the entry from the negative cache.
        triedAndFailed.remove(lastHop);
        
        // NB: learnLocalRoute takes care of the nity-gritty
        learnLocalRoute(lastHop);
      }
    } catch(Exception whatever) {
      // If the above failed, we may still be able to route the message.
      whatever.printStackTrace();
    }
    
    try {
      // If this peer is the final destination, then we're done. Just let
      // it be pushed up the stack. We must not put back our header;
      // it is now meaningless and none of the upper layers business.
      // All we have to do is to restore the end-2-end src and dest
      // so that the endpoint demux routine can do its job.
      if (destPeer.equals(localPeerAddr)) {
        // Since the destination is the local peer, it might be a good
        // optimization to learn the reverse route now, if there is one
        // Now see if the previous hop has a reverse route to the source peer.
        if (nbOfHops != 0) {
          setRoute(new Route(srcPeer,
          lastHop,
          nbOfHops,
          routerMsg.getReverseGateways()));
        }
        // Clear the forward gateway of the message since the message
        // has been delivered.
        routerMsg.setForwardGateways(null);
        // Removing the header.
        msg.removeElement(EndpointRouterMessage.Name);
        // Adding the updated header.
        msg.addElement(
        msg.newMessageElement(EndpointRouterMessage.Name,
        null,
        routerMsg.getInputStream()));
        
        msg.setSourceAddress(origSrcAddr);
        msg.setDestinationAddress(origDstAddr);
        endpoint.demux(msg);
        return;
      }
      
      boolean headerIsChanged = false;
      
      // Get the next peer into the forward route
      String nextHop = null;
      if (routerMsg.getForwardGateways() != null) {
        nextHop = getNextHop(routerMsg.getForwardGateways());
      }
      if (nextHop == null) {
        
        // No next hop. Try to use destPeer instead.
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("No next hop in forward gateways - Try to use destination as next hop");
        nextHop = destPeer;
        // Clear the forward path which is probably wrong
        routerMsg.setForwardGateways(null);
        // Do we have a reverse route for the source ?
        Route reverseRoute = getRoute(destPeer);
        if (reverseRoute != null) {
          routerMsg.setReverseGateways(reverseRoute.gateways);
        }
        headerIsChanged = true;
      }
      
      if ((isLocalRoute(destPeer)) && (!nextHop.equals(destPeer))) {
        // There is a local route - use it
        // Clear the forward path which is probably wrong
        
        // Do we have a reverse route for the source ?
        Route reverseRoute = getRoute(destPeer);
        if (reverseRoute != null) {
          routerMsg.setReverseGateways(reverseRoute.gateways);
        }
        headerIsChanged = true;
        nextHop = destPeer;
      }
      
      if (headerIsChanged) {
        // Change the router message within the message
        // because we want to modify it.
        // Removing the header.
        // Removing the header.
        msg.removeElement(EndpointRouterMessage.Name);
        // Adding the updated header.
        msg.addElement(
        msg.newMessageElement(EndpointRouterMessage.Name,
        null,
        routerMsg.getInputStream()));
      }
      
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("forwarding to " + nextHop);
      EndpointMessenger messenger = getTransportMessenger(nextHop, true);
      
      // Build a disposable RouterMessenger around it that will add our
      // header.
      EndpointMessenger routerMessenger =  new RouterMessenger(messenger,
      origDstAddr,
      endpoint,
      this,
      false);
      
      routerMessenger.sendMessage(msg);
      
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("Message has been forwarded to the next hop");
      
    } catch (Exception e) {
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("failed to deliver or forward: " + e);
    }
  }
  
  // Get the next hop within a vector of gateways
  private String getNextHop(Vector v) {
    if ((v == null) || (v.size() == 0)) {
      // Empty vector.
      return null;
    }
    // Find the local peer within the vector
    String nextHop = null;
    int i = v.indexOf(localPeerAddr);
    if (i == -1) {
      // The local peer is not into the vector. Since we have got that
      // message, the best we can do is to send it to the first gateway
      // in the forward path.
      try {
        nextHop =  (String) v.elementAt(0);
      } catch (Exception ez1) {
        // Should not fail, but if it does, there is not much we can do
        return null;
      }
      return nextHop;
    }
    // Found the local peer within the vector of gateways. Get the next gateway
    try {
      nextHop =  (String) v.elementAt(i + 1);
    } catch (Exception ez1) {
      // There is no next hop
      return null;
    }
    return nextHop;
  }
  
  private Hashtable triedAndFailed = new Hashtable();
  
  public EndpointAddress checkPeer(String peer) {
    
    if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("checkPeer peer= " + peer);
    
    // CheckPeer is realy lazy because what it does is expensive.
    // When needed, the negative info that prevents its from working
    // too much is removed. (see the calls to learnLocalRoute).
    
    Long lastTry = (Long) triedAndFailed.get(peer);
    if (lastTry != null) {
      long diff = System.currentTimeMillis() - lastTry.longValue();
      if (diff > 0 && diff < 300000) {
        // Too early to retry (less than 5 minutes).
        return null;
      } else {
        // It is ancient knowlege remove it.
        triedAndFailed.remove(peer);
      }
    }
    // Never tried or it was a long time ago.
    
    // Get (locally) the advertisement of this peer
    Enumeration advs = null;
    PeerAdvertisement adv = null;
    
    try {
      advs = getPeerAdv(peer);
      
      if (advs == null || !advs.hasMoreElements()) {
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("   no advertisement");
        
        // Can't keep negative info in that case; the absence of adv
        // is too volatile. We want to take advantage of one as soon
        // as it appears; notably during startup.
        return null;
      }
      
      while (advs.hasMoreElements()) {
        
        adv = (PeerAdvertisement) advs.nextElement();
        
        // Get its EndpointService advertisement
        TextElement endpParam = (TextElement)
        adv.getServiceParam(PeerGroup.endpointClassID);
        
        if (endpParam == null) {
          if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("checkPeer: no Endpoint Params");
          continue;
        }
        Enumeration endps = endpParam.getChildren("Addr");
        if (!endps.hasMoreElements()) {
          if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("checkPeer: no Addresses in adv");
          continue;
        }
        
        Vector addrs = new Vector();
        while (endps.hasMoreElements()) {
          String saddr = "";
          try {
            saddr =
            ((TextElement) endps.nextElement()).getTextValue();
            addrs.addElement(endpoint.newEndpointAddress(saddr));
            
          } catch (Exception e) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("bad address");
            continue;
          }
        }
        if (addrs.size() > 0) {
          EndpointAddress bestAddr = null;
          bestAddr = getBestLocalRoute(addrs.elements());
          if (bestAddr != null) {
            // Found a direct route. Return it.
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("found direct route");
            return bestAddr;
          }
        }
      }
    } catch (Exception e) {
      if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("    failed with " + e);
      triedAndFailed.put(peer,
      new Long(System.currentTimeMillis()));