PkgAgentSystem.Messaging
Class Message

java.lang.Object
  |
  +--PkgAgentSystem.Messaging.Message

Direct Known Subclasses:

AcceptMessage, BroadcastMessage, ChallengeIdentityMessage, DeclineMessage, MessageReply, RejectMessage, ResultMessage, SendStatementsMessage, SignedMessage, TerminateAgentMessage

public abstract class Message

extends Object

implements Serializable, Cloneable

A message, which can be sent from one agent to another.
Subclasses MUST be serializable, else messaging will NOT work!

ATTENTION: The following is NOT allowed:
If a message contains a system class or an agent-system class, this class MUST NOT store a contained agent-class in binary form. It may contain it as an field.
If the data is automatically restored from the stream during deserialization or read through readObject, there is no problem. Not allowed is reading it in as an byte array and restoring it from a different (self created) ObjectInputStream (via a ByteArrayInputStream).
The problem is the following: When the class is deserialized through the classloader of the receiving agent, this class will be loaded (ot tried to be loaded) by the classloader of the system-class/agent-system class, which is the primordial classloader. If this is successful, there will be no possibility to cast it to the local type of the agent (which is loaded through the agents classloader!). The data will not be available for the receiver.
Example: java.security.SignedObject will not work.
Example: SignedMessage PkgAgentSystem.Messaging.SignedMessage does work.

Version:

1.0, 1.7.2000

Author:

Michael Sonntag

See Also:

AgentBase, AgentSystem.sendMessage(AgentBase,Message), Serialized Form

Field Summary

protected AgentIdentity	addressee The recipient of the message.
protected long	convTypeID ID of the type of the conversation, which handles this message.
protected long	destConvID ID of the conversation at the destination of the message.
protected AgentIdentity	sender The sender of the message
protected long	srcConvID ID of the conversation at the source of the message.

Constructor Summary

protected	Message() Create a new and empty message.
protected	Message(AgentIdentity sender, AgentIdentity addressee, long convTypeID, long srcConvID, long destConvID) Creates a new message from one agent to another.
protected	Message(Message inReplyTo) Create a new message in reply to another one.

Method Summary

Message	copy() Returns a shallow copy of this message.
AgentIdentity	getAddressee() Returns the identity of the recipient of the message.
long	getConversationTypeID() Returns the ID of the type of conversations handling this message.
long	getDestConversationID() Returns the ID of the conversation at the recipient of the message.
AgentIdentity	getSender() Returns the identity of the sender of the message.
long	getSrcConversationID() Returns the ID of the conversation at the sender of the message.
void	setDestConversationID(long id) Set the ID for the conversation at the destination.
void	setSrcConversationID(long id) Set the ID for the conversation at the sender.
String	toString() Returns a string representation of this message.

Methods inherited from class java.lang.Object

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

Field Detail

srcConvID

protected long srcConvID

ID of the conversation at the source of the message.

destConvID

protected long destConvID

ID of the conversation at the destination of the message.

convTypeID

protected long convTypeID

ID of the type of the conversation, which handles this message.

sender

protected transient AgentIdentity sender

The sender of the message

addressee

protected transient AgentIdentity addressee

The recipient of the message. This might be null, although this is not allowed in the constructor. The subclass BroadcastMessage has a constructor where this is allowed/necessary (broadcasts have no single recipient).

Constructor Detail

Message

protected Message()

Create a new and empty message. Necessary, so we get no default public constructor. No class should be able to create a message without the necessary parameters.

Message

protected Message(AgentIdentity sender,
                  AgentIdentity addressee,
                  long convTypeID,
                  long srcConvID,
                  long destConvID)

Creates a new message from one agent to another.

Parameters:

sender - the identity of the sender. Must be provided.

addressee - the identity of the recipient. Must be provided.

convTypeID - ID of the type of the conversation. Must not be 0.

srcConvID - ID of the conversation at the source. May be 0 for replies to unknown conversations, ... (there is no conversation with those).

destConvID - ID of the conversation at the recipient. May be 0 for initial messages (starting a conversation) and broadcasts.

Message

protected Message(Message inReplyTo)

Create a new message in reply to another one. The addressee is copied to the sender and the sender to the recipient. The conversation type ID stays the same. The source conversation ID is copied to the destionation conversation ID and reverse.

Method Detail

setDestConversationID

public void setDestConversationID(long id)

Set the ID for the conversation at the destination. Only allowed if the ID is currently 0.

Parameters:

id - the id of the conversation at the destination (may not be 0)

setSrcConversationID

public void setSrcConversationID(long id)

Set the ID for the conversation at the sender. Only allowed if the ID is currently 0.

Parameters:

id - the id of the conversation at the sender (may not be 0)

getSrcConversationID

public long getSrcConversationID()

Returns the ID of the conversation at the sender of the message.

Returns:

conversation ID of the sender

getDestConversationID

public long getDestConversationID()

Returns the ID of the conversation at the recipient of the message.

Returns:

conversation ID of the recipient

getConversationTypeID

public long getConversationTypeID()

Returns the ID of the type of conversations handling this message.

Returns:

conversation type ID of this message

getSender

public AgentIdentity getSender()

Returns the identity of the sender of the message.

Returns:

identity of the sender

getAddressee

public AgentIdentity getAddressee()

Returns the identity of the recipient of the message.

Returns:

identity of the recipient

copy

public Message copy()
             throws MessageException

Returns a shallow copy of this message.

Returns:

a clone of this message

Throws:

MessageException - if this message cannot be cloned

toString

public String toString()

Returns a string representation of this message. The representation is the name of the actual class of the message and the names of the sender and the recipient.

Returns:

string representation of this message

Overrides:

toString in class Object