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java.lang.Object
   |
   +----edu.utah.janos.antsr.core.Entity
           |
           +----edu.utah.janos.antsr.core.Application
                   |
                   +----edu.utah.janos.antsr.route.DynamicRouteApp

Summary

public class  DynamicRouteApp
     extends edu.utah.janos.antsr.core.Application
{
          // Fields 7
     public static final int APP_PORT;
     private static final int MAXROUTESPERUPDATE;
     private static final String[] defaults;
     private final DynamicRouteEvents events;
     private Node node;
     private boolean suppressTriggerEvents;
     private DynamicRouteTable table;

          // Constructors 1
     public DynamicRouteApp();

          // Methods 14
     private void clearChangeFlags();
     private void expireEntries(DynamicRouteEvent);
     private void gcEntries(DynamicRouteEvent);
     private void initApp();
     private void initEvents();
     boolean newRouteInfo(int, int, int, String, long);
     public void receive(Capsule);
     void scheduleTrigger(long);
     private void sendRouteMessages(int);
     private void sendRouteWorker(DynamicRouteEntry, int);
     private void sendUpdate(DynamicRouteEntry, Vector);
     public void setArgs(KeyArgs) throws InvalidKeyArgsException;
     public void start();
     void suppressTriggerEvents(boolean);
}

The "app" that maintains a node's dynamic routing tables.

This is really just an app so it can justify sending capsules off without priming them off some other capsule. (All this code used to be part of DynamicRouteTable.)

Understands the default '-port' argument that all apps grok.

Author:

Janos Ministry of Development , David Wetherall

Fields

· APP_PORT

Summary  |  Top

   public static final int APP_PORT

   private static final String[] defaults

   private static final int MAXROUTESPERUPDATE

Maximum number of route updates to stuff into a single RouteUpdateCapsule. (Each update costs 5 bytes).

   private DynamicRouteTable table

The table this app is keeping up to date.

   private Node node

The node this table is maintained on.

   private boolean suppressTriggerEvents

Used for suppressing triggered updates. Triggered updates are scheduled when the routing table is changed. Once a triggered update is scheduled, futher updates are suppressed until the trigger update is executed.

   private final DynamicRouteEvents events

The queue of timers and events that cause updates.

Constructors

· DynamicRouteApp

Summary  |  Top

   public DynamicRouteApp() 

App constructors can't do anything useful. Ideally, I would like to set this.node and this.table, but I can't because the node hasn't been plugged into this app yet, and I need to node to get the table...

   public void setArgs(KeyArgs k)  throws InvalidKeyArgsException

Parse command line arguments.

See the class description for a list of the arguments and their meaning.

Overrides:

setArgs in class Application

   private void initEvents() 

Initialize the event queue.

   private void initApp() 

Do initialization of the App.

XXX one-time function.

   public void start() 

The active route table logic.

Harmless if invoked on a static table.

Overrides:

start in class Application

   private void expireEntries(DynamicRouteEvent e) 

Walks all routes and moves expired routes into the gcPool.

   private void gcEntries(DynamicRouteEvent e) 

Delete all routes in the gcPool that have expired. Such routes are lost for all time.

   private void clearChangeFlags() 

Mark all routes as 'unchanged'.

   private void sendUpdate(DynamicRouteEntry g, 
                           Vector r) 

Send a route update to the given node.

XXX this is completely out of synch with the new world order.

   private void sendRouteWorker(DynamicRouteEntry gatewayRoute, 
                                int cause) 

Send a message to a host about a route. The given host should be a gateway host for this node.

   private void sendRouteMessages(int cause) 

Send a message to each gateway and to host which has a cost of "1" to reach. For each gateway send a long list of route entries.

XXX this is O(N * N) when N is the *number of routes*!

Parameter	Description
cause	the reason this was invoked (Trigger or periodic).

   public void receive(Capsule unknownCap) 

Receive and process RouteUpdateCapsule. RouteUpdateCapsules contain zero or more route update records. Each "record" consists of a destination and a "distance" to that destination.

Parameter	Description
unknownCap	the RouteUpdateCapsule.

Overrides:

receive in class Application

   boolean newRouteInfo(int dest, 
                        int dist, 
                        int gw, 
                        String gwPhysAddr, 
                        long now) 

Provide new information for a single route. If the info is useful, update the route table. It is the caller's responsibility to schedule a trigger update if there are changes to the route table.

Invoked by exclusivly by RouteUpdateCapsule.evalutate.

Parameter	Description
dest	the active address of the destination to update a route to
dist	the distance to that node from the gateway
gw	the active address of the gateway (the "next hop" to dest)
gwPhysAddr	the physical address of the gateway
now	what time is it my dear?

Returns:

true if a change was made; false if not.

See Also: RouteUpdateCapsule

   void suppressTriggerEvents(boolean doit) 

Suppress scheduling of further trigger events. Or don't.

   void scheduleTrigger(long when) 

Schedule a trigger event for some time after 'when'. If triggers are surpressed (because one has already been scheduled but not executed) the request is dropped on the floor.

Invoked in here and by RouteUpdateCapsule.

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