Class Node

java.lang.Object
  Node

Direct Known Subclasses:

DVNode

public abstract class Node
extends java.lang.Object

Abstract base class of DV and LS node types. Implements common functionality -- most everything but timestep based routing table update.

Field Summary

protected boolean	failed Indicator of whether or not this node has failed
protected java.util.HashMap<Node,java.lang.Integer>	lastHeardDelay Each neighbor has a time since last heard from
protected int	lastUpdatedSlot Time slot in which we last ran
protected java.util.LinkedHashSet<Node>	neighbor Each node has a current list of neighbors
protected static MyRandom	rand
protected int	uid Each node has an integer UID.

Constructor Summary

Node()

Method Summary

protected abstract void	failureEvent() Invoked when this node fails.
RoutingTable	getRoutingTable()
int	getUID()
boolean	hasFailed()
protected abstract void	neighborFailureEvent(Node neighbor) Invoked when a timeout indicates that a neighbor node has failed.
void	oracleComputeRoutingTable() Fills in the routing table using an oracle (i.e., reliable/correct) view of network connectivity.
void	oracleFillTable(RoutingTable rt) Fills in the routing table using an oracle (i.e., reliable/correct) view of network connectivity.
protected abstract void	processUpdate(UpdatePacket p) Called for each update packet in this node's queue when it is selected to run during a time step.
protected abstract void	recoveryEvent() Invoked when this node recovers from a failure.
protected void	sendUpdatePacket(Node dest, UpdatePacket p) Send an update packet
boolean	setHasFailed(boolean f) Allows manipulation of failure/recovery of this node.
void	setupNeighborInformation() Called as an initialization step, once the network topology is finalized.
protected abstract void	startUpdate() When this node is selected to run during a time step, the "driver" code in Node.java: first calls this routine (startUpdate()) then with high, but not certain, probability calls processUpdate() for each update packet in the node's queue
protected abstract void	stopUpdate() See startUpdate().
void	swapInQueues() Swaps the current and future in queues.
void	takeStep() Causes node to read currentInQueue of update packets and act on them.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

uid

protected int uid

Each node has an integer UID. (They're consecutive.)

neighbor

protected java.util.LinkedHashSet<Node> neighbor

Each node has a current list of neighbors

lastHeardDelay

protected java.util.HashMap<Node,java.lang.Integer> lastHeardDelay

Each neighbor has a time since last heard from

lastUpdatedSlot

protected int lastUpdatedSlot

Time slot in which we last ran

failed

protected boolean failed

Indicator of whether or not this node has failed

rand

protected static MyRandom rand

Constructor Detail

Node

public Node()

Method Detail

getUID

public int getUID()

getRoutingTable

public RoutingTable getRoutingTable()

hasFailed

public boolean hasFailed()

oracleComputeRoutingTable

public void oracleComputeRoutingTable()

Fills in the routing table using an oracle (i.e., reliable/correct) view of network connectivity.

oracleFillTable

public void oracleFillTable(RoutingTable rt)

Fills in the routing table using an oracle (i.e., reliable/correct) view of network connectivity.

setupNeighborInformation

public void setupNeighborInformation()

Called as an initialization step, once the network topology is finalized. Node should do whatever it has to do to understand who it thinks its neighbors are.

sendUpdatePacket

protected void sendUpdatePacket(Node dest,
                                UpdatePacket p)
                         throws java.lang.IllegalArgumentException

Send an update packet

Throws:

java.lang.IllegalArgumentException

swapInQueues

public void swapInQueues()

Swaps the current and future in queues. (Called by Network code each time it is asked to take a step.)

takeStep

public void takeStep()

Causes node to read currentInQueue of update packets and act on them.

setHasFailed

public boolean setHasFailed(boolean f)

Allows manipulation of failure/recovery of this node.

startUpdate

protected abstract void startUpdate()

When this node is selected to run during a time step, the "driver" code in Node.java:

1. first calls this routine (startUpdate())
2. then with high, but not certain, probability calls processUpdate() for each update packet in the node's queue
3. (1) and (3) allow some flexibility in the implementation of different (sub)classes of node, without having to meddle with the code in Node.java.

processUpdate

protected abstract void processUpdate(UpdatePacket p)

Called for each update packet in this node's queue when it is selected to run during a time step.

stopUpdate

protected abstract void stopUpdate()

See startUpdate().

failureEvent

protected abstract void failureEvent()

Invoked when this node fails.

recoveryEvent

protected abstract void recoveryEvent()

Invoked when this node recovers from a failure.

neighborFailureEvent

protected abstract void neighborFailureEvent(Node neighbor)

Invoked when a timeout indicates that a neighbor node has failed.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object