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

	    return false;
	}
	r.display();

        // Here we're synchronized. Check that we do not have that route
        // after all.
        if (directRoutes.containsKey(r.dest)) return false; // nothing new.

	// Check if the route makes senses (loop detection)
	if (!checkRoute (r)) {
	    // Route is invalid. Drop it.
	    if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug ("Route is invalid");
	    return false;
	}

 	if ( !directRoutes.containsKey (r.router)) {
 	    // We don't know how to reach this route. Ignore.
 	    if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug ("Unreachable route - ignore");
 	    return false;
 	}

	// If the last hop is not in the vector of gateways, add it.
	try {
	    String lastInVector = (String) r.gateways.elementAt (0);
	    if ((lastInVector != null) && !lastInVector.equals (r.router)) {
        //PDA requirement 18.02.2002
        // Vector.add -> Vector.insertElementAt
        // r.gateways.add (0, r.router);
		r.gateways.insertElementAt (r.router, 0);
	    }
	} catch (Exception ez1) {
	    // The vector must be empty, which is not supposed
	    // to happen.
	    if (LOG.isEnabledFor(Priority.WARN)) LOG.warn ("Got an empty route - discard");
	    return false;
	}

        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("     srcPeer= " + srcPeer);
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("    destPeer= " + destPeer);
	    if (lastHop != null) if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("     lastHop= " + lastHop);
	    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);
        //PDA requirement 18.02.2002
        // Vector.add -> Vector.addElement
		// tmp.add (lastHop);
		tmp.addElement (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 RouterMessenger around it that will add our header.
	    EndpointMessenger routerMessenger =  new RouterMessenger(messenger,
								     origDstAddr,
								     endpoint,
								     this);

            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();