routing
Class SprayAndWaitRouter

java.lang.Object
  routing.MessageRouter
      routing.ActiveRouter
          routing.SprayAndWaitRouter

public class SprayAndWaitRouter
extends ActiveRouter

Implementation of Spray and wait router as depicted in Spray and Wait: An Efficient Routing Scheme for Intermittently Connected Mobile Networks by Thrasyvoulos Spyropoulus et al.

Field Summary

static java.lang.String	BINARY_MODE identifier for the binary-mode setting ("binaryMode")
protected int	initialNrofCopies
protected boolean	isBinary
static java.lang.String	MSG_COUNT_PROPERTY Message property key
static java.lang.String	NROF_COPIES identifier for the initial number of copies setting ("nrofCopies")
static java.lang.String	SPRAYANDWAIT_NS SprayAndWait router's settings name space ("SprayAndWaitRouter")

Fields inherited from class routing.ActiveRouter

DELETE_DELIVERED_S, deleteDelivered, RESPONSE_PREFIX, sendingConnections, TTL_CHECK_INTERVAL

Fields inherited from class routing.MessageRouter

B_SIZE_S, DENIED_NO_SPACE, DENIED_OLD, DENIED_TTL, DENIED_UNSPECIFIED, MSG_TTL_S, msgTtl, Q_MODE_FIFO, Q_MODE_RANDOM, RCV_OK, SEND_QUEUE_MODE_S, TRY_LATER_BUSY

Constructor Summary

	SprayAndWaitRouter(Settings s)
protected	SprayAndWaitRouter(SprayAndWaitRouter r) Copy constructor.

Method Summary

boolean	createNewMessage(Message msg) Creates a new message to the router.
protected java.util.List<Message>	getMessagesWithCopiesLeft() Creates and returns a list of messages this router is currently carrying and still has copies left to distribute (nrof copies > 1).
Message	messageTransferred(java.lang.String id, DTNHost from) This method should be called (on the receiving host) after a message was successfully transferred.
int	receiveMessage(Message m, DTNHost from) Try to start receiving a message from another host.
SprayAndWaitRouter	replicate() Creates a replicate of this router.
protected void	transferDone(Connection con) Called just before a transfer is finalized (by ActiveRouter.update()).
void	update() Checks out all sending connections to finalize the ready ones and abort those whose connection went down.

Methods inherited from class routing.ActiveRouter

addToSendingConnections, canStartTransfer, changedConnection, checkReceiving, dropExpiredMessages, exchangeDeliverableMessages, getConnections, getMessagesForConnected, getOldestMessage, init, isSending, isTransferring, makeRoomForMessage, makeRoomForNewMessage, requestDeliverableMessages, shuffleMessages, startTransfer, transferAborted, tryAllMessages, tryAllMessagesToAllConnections, tryMessagesForConnected, tryMessagesToConnections

Methods inherited from class routing.MessageRouter

addApplication, addToMessages, compareByQueueMode, deleteMessage, getApplications, getBufferSize, getFreeBufferSize, getHost, getMessage, getMessageCollection, getNrofMessages, getRoutingInfo, hasMessage, isDeliveredMessage, isIncomingMessage, messageAborted, putToIncomingBuffer, removeFromIncomingBuffer, removeFromMessages, sendMessage, sortByQueueMode, toString

Methods inherited from class java.lang.Object

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

Field Detail

NROF_COPIES

public static final java.lang.String NROF_COPIES

identifier for the initial number of copies setting ("nrofCopies")

See Also:

Constant Field Values

BINARY_MODE

public static final java.lang.String BINARY_MODE

identifier for the binary-mode setting ("binaryMode")

See Also:

Constant Field Values

SPRAYANDWAIT_NS

public static final java.lang.String SPRAYANDWAIT_NS

SprayAndWait router's settings name space ("SprayAndWaitRouter")

See Also:

Constant Field Values

MSG_COUNT_PROPERTY

public static final java.lang.String MSG_COUNT_PROPERTY

Message property key

See Also:

Constant Field Values

initialNrofCopies

protected int initialNrofCopies

isBinary

protected boolean isBinary

Constructor Detail

SprayAndWaitRouter

public SprayAndWaitRouter(Settings s)

SprayAndWaitRouter

protected SprayAndWaitRouter(SprayAndWaitRouter r)

Copy constructor.

Parameters:

r - The router prototype where setting values are copied from

Method Detail

receiveMessage

public int receiveMessage(Message m,
                          DTNHost from)

Description copied from class: MessageRouter

Try to start receiving a message from another host.

Overrides:

receiveMessage in class ActiveRouter

Parameters:

m - Message to put in the receiving buffer

from - Who the message is from

Returns:

Value zero if the node accepted the message (RCV_OK), value less than zero if node rejected the message (e.g. DENIED_OLD), value bigger than zero if the other node should try later (e.g. TRY_LATER_BUSY).

messageTransferred

public Message messageTransferred(java.lang.String id,
                                  DTNHost from)

Description copied from class: MessageRouter

This method should be called (on the receiving host) after a message was successfully transferred. The transferred message is put to the message buffer unless this host is the final recipient of the message.

Overrides:

messageTransferred in class ActiveRouter

Parameters:

id - Id of the transferred message

from - Host the message was from (previous hop)

Returns:

The message that this host received

createNewMessage

public boolean createNewMessage(Message msg)

Description copied from class: MessageRouter

Creates a new message to the router.

Overrides:

createNewMessage in class ActiveRouter

Parameters:

msg - The message to create

Returns:

True if the creation succeeded, false if not (e.g. the message was too big for the buffer)

update

public void update()

Description copied from class: ActiveRouter

Checks out all sending connections to finalize the ready ones and abort those whose connection went down. Also drops messages whose TTL <= 0 (checking every one simulated minute).

Overrides:

update in class ActiveRouter

See Also:

ActiveRouter.addToSendingConnections(Connection)

getMessagesWithCopiesLeft

protected java.util.List<Message> getMessagesWithCopiesLeft()

Creates and returns a list of messages this router is currently carrying and still has copies left to distribute (nrof copies > 1).

Returns:

A list of messages that have copies left

transferDone

protected void transferDone(Connection con)

Called just before a transfer is finalized (by ActiveRouter.update()). Reduces the number of copies we have left for a message. In binary Spray and Wait, sending host is left with floor(n/2) copies, but in standard mode, nrof copies left is reduced by one.

Overrides:

transferDone in class ActiveRouter

Parameters:

con - The connection whose transfer was finalized

replicate

public SprayAndWaitRouter replicate()

Description copied from class: MessageRouter

Creates a replicate of this router. The replicate has the same settings as this router but empty buffers and routing tables.

Specified by:

replicate in class MessageRouter

Returns:

The replicate