message
Class Message

java.lang.Object
  message.Message

All Implemented Interfaces:

java.lang.Comparable<Message>, BasicMessage

Direct Known Subclasses:

BatchSizeMessage, ChannelEstablishMessage, ChannelMessage, ChannelReleaseMessage, ReplyMessage

public abstract class Message
extends java.lang.Object
implements BasicMessage, java.lang.Comparable<Message>

Basic abstract class for all types of messages the InputOutputHandler is capable of transmitting.

Provides a byte array containing the message itself in an exchangeable form (see byteMessage) and several manipulable properties for internal usage only (e. g. by a mix or client).

Author:

Karl-Peter Fuchs

Field Summary

private byte[]	byteMessage Byte representation of this message.
private User	channel Reference on the user/channel. this message belongs to.
private int	CHANNEL_ID Identifier of the channel/user this message belongs to.
private static NetworkClockController	clock Reference on component NetworkClock (used to set variable timeOfReceival).
private int	messageID Identifier for this message.
private int	NEXT_MIX_CHANNEL_ID Identifier of the channel/user this message belongs to for the next mix of the cascade.
private int	payloadLength Only a certain part of byteMessage must be transmitted to the cascade's next mix (Some parts (e. g. the session key for the corresponding mix) are not supposed to be sent).
private int	startIndexOfPayload Only a certain part of byteMessage must be transmitted to the cascade's next mix (Some parts (e. g. the session key for the corresponding mix) are not supposed to be sent).
private long	timeOfReceival Point of time (timestamp), this message was received by the corresponding mix.

Constructor Summary

Message(byte[] byteMesssage)
Message constructor used by client.

Message(byte[] byteMesssage, User channel, int startIndexOfPayload, int payloadLength)
Message constructor used by mix.

Method Summary

int	compareTo(Message message) Implements the Comparable interface's compareTo() method.
byte[]	getByteMessage() Returns the byte representation of this message (byteMessage).
User	getChannel() Returns a reference on the channel/user this message belongs to.
int	getChannelID() Returns an identifier for the channel/user this message belongs to.
int	getMessageID() Returns an identifier for this message.
int	getNextMixChannelID() Returns an identifier for the channel/user this message belongs to, used by the next mix of the cascade.
long	getTimeOfReceival() Returns the point of time (timestamp), this message was received.
void	setByteMessage(byte[] byteMessage) Sets the byte representation of this message (byteMessage) to the bypassed array.
void	setMessageID(int newIdentifier) Sets this message's identifier to the bypassed value.
void	setPayloadRange(int startIndexOfPayload, int payloadLength) Only a certain part of the message array must be transmitted to the cascade's next mix (Some parts (e. g. the session key for the corresponding mix) are not supposed to be sent).
void	setTimeOfReceival(long newTimeOfReceival) Sets the point of time (timestamp), this message was received to the bypassed value.

Methods inherited from class java.lang.Object

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

Field Detail

CHANNEL_ID

private final int CHANNEL_ID

Identifier of the channel/user this message belongs to.

NEXT_MIX_CHANNEL_ID

private final int NEXT_MIX_CHANNEL_ID

Identifier of the channel/user this message belongs to for the next mix of the cascade.

messageID

private int messageID

Identifier for this message.

clock

private static NetworkClockController clock

Reference on component NetworkClock (used to set variable timeOfReceival).

See Also:

timeOfReceival

timeOfReceival

private long timeOfReceival

Point of time (timestamp), this message was received by the corresponding mix.

startIndexOfPayload

private int startIndexOfPayload

Only a certain part of byteMessage must be transmitted to the cascade's next mix (Some parts (e. g. the session key for the corresponding mix) are not supposed to be sent). Which part is relevant depends on the type of message.

This variable defines the offset for the part to be transmitted.

This variable must/can be set automatically in the constructor of any subclass.

See Also:

payloadLength

payloadLength

private int payloadLength

Only a certain part of byteMessage must be transmitted to the cascade's next mix (Some parts (e. g. the session key for the corresponding mix) are not supposed to be sent). Which part is relevant depends on the type of message.

This variable defines the length for the part to be transmitted.

This variable must/can be set automatically in the constructor of any subclass.

See Also:

payloadLength

channel

private User channel

Reference on the user/channel. this message belongs to.

byteMessage

private byte[] byteMessage

Byte representation of this message. Contains all data that was received or shall be sent via network.

Constructor Detail

Message

public Message(byte[] byteMesssage,
               User channel,
               int startIndexOfPayload,
               int payloadLength)

Message constructor used by mix.

Constructs a new Message with the submitted content ( byteMesssage) for the bypassed user/channel.

Parameters:

byteMesssage - Byte representation of the message (as received from the client/previous mix).

channel - Reference on the user/channel this message belongs to.

startIndexOfPayload - See instance variable startIndexOfPayload.

payloadLength - See instance variable payloadLength.

Message

public Message(byte[] byteMesssage)

Message constructor used by client.

Constructs a new Message with the submitted content ( byteMesssage).

Parameters:

byteMesssage - Byte representation of the message (can be empty).

Method Detail

getNextMixChannelID

public int getNextMixChannelID()

Returns an identifier for the channel/user this message belongs to, used by the next mix of the cascade.

Specified by:

getNextMixChannelID in interface BasicMessage

Returns:

Identifier for the channel/user this message belongs to, used by the next mix of the cascade.

getChannelID

public int getChannelID()

Returns an identifier for the channel/user this message belongs to.

Specified by:

getChannelID in interface BasicMessage

Returns:

Identifier for the channel/user this message belongs to.

getMessageID

public int getMessageID()

Returns an identifier for this message.

Specified by:

getMessageID in interface BasicMessage

Returns:

Identifier for this message.

setMessageID

public void setMessageID(int newIdentifier)

Sets this message's identifier to the bypassed value.

Specified by:

setMessageID in interface BasicMessage

Parameters:

newIdentifier - Value this message's identifier shall be set to.

setPayloadRange

public void setPayloadRange(int startIndexOfPayload,
                            int payloadLength)

Only a certain part of the message array must be transmitted to the cascade's next mix (Some parts (e. g. the session key for the corresponding mix) are not supposed to be sent). Which part is relevant depends on the type of message.

This method defines the offset and length of the part to be transmitted.

Specified by:

setPayloadRange in interface BasicMessage

Parameters:

startIndexOfPayload - Offset of the part to be transmitted.

payloadLength - Length of the part to be transmitted.

getChannel

public User getChannel()

Returns a reference on the channel/user this message belongs to.

Specified by:

getChannel in interface BasicMessage

Returns:

Reference on the channel/user this message belongs to.

getTimeOfReceival

public long getTimeOfReceival()

Returns the point of time (timestamp), this message was received.

Specified by:

getTimeOfReceival in interface BasicMessage

Returns:

Point of time (timestamp), this message was received.

setTimeOfReceival

public void setTimeOfReceival(long newTimeOfReceival)

Sets the point of time (timestamp), this message was received to the bypassed value.

Specified by:

setTimeOfReceival in interface BasicMessage

Parameters:

newTimeOfReceival - Point of time (timestamp), this message was received.

getByteMessage

public byte[] getByteMessage()

Returns the byte representation of this message (byteMessage).

Specified by:

getByteMessage in interface BasicMessage

Returns:

Byte representation of this message.

setByteMessage

public void setByteMessage(byte[] byteMessage)

Sets the byte representation of this message (byteMessage) to the bypassed array.

Specified by:

setByteMessage in interface BasicMessage

Parameters:

byteMessage - New content for this message.

compareTo

public int compareTo(Message message)

Implements the Comparable interface's compareTo() method. Compares this Message with the specified Message for order (criterion: alphabetic order of this Message's payload. Returns a negative integer, zero, or a positive integer as this Message is less than, equal to, or greater than the specified Message.

Specified by:

compareTo in interface java.lang.Comparable<Message>

Parameters:

message - The Message to be compared.

Returns:

-1, 0, or 1 as this Message is less than, equal to, or greater than the specified Message .

See Also:

setPayloadRange(int, int)