ca.mcgill.cs.postina.scribe
Class MessageID

java.lang.Object
  ca.mcgill.cs.postina.scribe.MessageID

All Implemented Interfaces:

java.io.Serializable

public class MessageID
extends java.lang.Object
implements java.io.Serializable

A messageID is a unique identifier of a message. The messageID is used to implement reliability.

Version:

8-Jan-08

Author:

Dominik Zindel

See Also:

Serialized Form

Field Summary

private int	counter An integer number counting the number of times the messages has already been sent over the network.
private rice.p2p.commonapi.NodeHandle	destinationHandle
private rice.p2p.commonapi.Id	destinationId
private int	messageNumber An integer number.
private rice.p2p.commonapi.Id	senderId The unique identifier of the originator of the message.
private long	sendTimeStamp The system time (milliseconds) at which the message was sent.
private static long	serialVersionUID

Constructor Summary

MessageID(rice.p2p.commonapi.Id senderId, rice.p2p.commonapi.Id destinationId, rice.p2p.commonapi.NodeHandle destinationHandle, int messageNumber)
The default constructor for a messageID

Method Summary

boolean	equals(java.lang.Object o)
int	getCounter() This method gets the number of times the message has already been sent.
rice.p2p.commonapi.NodeHandle	getDestinationHandle()
rice.p2p.commonapi.Id	getDestinationId()
int	getMessageNumber() This method gets the number of the message.
long	getRemainingTimeOut(long timeout) This method computes the time that is remaining before the message times out.
rice.p2p.commonapi.Id	getSenderId() This method gets the unique identifier of the sender of the message.
long	getSendTimeStamp() This method gets the Unix time stamp at which the message was sent the last time.
int	hashCode()
boolean	hasTimedOut(long timeout) This method checks if the message is older than the specified time.
void	incCounter() This message increases the counter of the number of times the message has been sent by one.
void	resetSendTimeStamp() This method resets the time stamp of the messageId to the current system time.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

counter

private int counter

An integer number counting the number of times the messages has already been sent over the network. This is used for reliability as a message is not resent an infinite number of times.

destinationHandle

private final rice.p2p.commonapi.NodeHandle destinationHandle

destinationId

private final rice.p2p.commonapi.Id destinationId

messageNumber

private final int messageNumber

An integer number. Note that this number is not unique in the network as each client has its own counter for the messageNumber. However, the combination of the ID of the sender and the messagenumber is guaranteed to be unique.

senderId

private final rice.p2p.commonapi.Id senderId

The unique identifier of the originator of the message. The senderId is used for all actions except sending the acknowledgment.

sendTimeStamp

private long sendTimeStamp

The system time (milliseconds) at which the message was sent.

Constructor Detail

MessageID

public MessageID(rice.p2p.commonapi.Id senderId,
                 rice.p2p.commonapi.Id destinationId,
                 rice.p2p.commonapi.NodeHandle destinationHandle,
                 int messageNumber)

The default constructor for a messageID

Parameters:

senderHandle - The Pastry-nodehandle of the originator of the message.

senderId - The unique Id (by Pastry) of the sender of the message.

messageNumber - The number of the message.

Method Detail

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

getCounter

public int getCounter()

This method gets the number of times the message has already been sent.

Returns:

The integer number of times the message has been sent so far.

getDestinationHandle

public rice.p2p.commonapi.NodeHandle getDestinationHandle()

Returns:

the destinationHandle

getDestinationId

public rice.p2p.commonapi.Id getDestinationId()

Returns:

the destinationId

getMessageNumber

public int getMessageNumber()

This method gets the number of the message.

Returns:

An integer number.

getRemainingTimeOut

public long getRemainingTimeOut(long timeout)

This method computes the time that is remaining before the message times out.

Parameters:

timeout - The timeout after which the message times out.

Returns:

A long number of milliseconds, representing the difference between timeout and the age of the message. If the message has already timed out (i.e. the return value would be negative), 0 is returned.

getSenderId

public rice.p2p.commonapi.Id getSenderId()

This method gets the unique identifier of the sender of the message.

Returns:

The Id of the originator of the message.

getSendTimeStamp

public long getSendTimeStamp()

This method gets the Unix time stamp at which the message was sent the last time.

Returns:

A long representing the Unix system time.

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

hasTimedOut

public boolean hasTimedOut(long timeout)

This method checks if the message is older than the specified time.

Parameters:

timeout - The minimum age in milliseconds of the message to return true.

Returns:

True if the message is at least timeout milliseconds olds, false otherwise.

incCounter

public void incCounter()

This message increases the counter of the number of times the message has been sent by one.

resetSendTimeStamp

public void resetSendTimeStamp()

This method resets the time stamp of the messageId to the current system time. This is used when a message has to be resent.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object