import java.io.*;
import java.util.*;
import java.lang.*;
import java.sql.Time;

/** This class represents the messages sent and received by LPs.
 * @author Yin Xiong
 * @version 2.0 (10/2006)
 */
  
public class Message implements Serializable, Comparable<Message> {
/**
 * Constants representing categories of messages that can be sent.
 * <ul>
 *  <li>Regular simulation messages
 *  <li>Simulation anti-messages (canceling a regular message)
 *  <li>Simulation straggler messages (regular messages that are behind GVT)
 *  <li>System monitoring requests
 *  <li>System monitoring reports
 *  <li>System steering requests
 *  <li>System steering acknowledgements
 * </ul>
 */
public enum MsgType { SIM_REGULAR, SIM_ANTI, SIM_STRAGGLER,
	SYSTEM_MONITOR, SYSTEM_STEER, SYSTEM_REPORT, SYSTEM_ACKNOWLEDGE,SIM_ENDSIM }

/**Tag that indicate whether this message has already been acknowledged by the 
   receiver */
 int tag;

/**Type of the message, matching one of the constants defined in this class. */
MsgType msgType;

/**(Simulation) time this message should occur.*/
//double timeStamp;
int timeStamp;

/**Message content*/
Object content;

/**Sender's {@link LogicalProcess#APPid APPid}, if sender is a 
 * {@link LogicalProcess}, or identifier, if sender is a monitoring/steering 
 * application. */
String senderAPPid;

/**Sender's LP number*/
int senderLP;

/**Sender's PE number*/
int senderPE;

/**Receiver's {@link LogicalProcess#APPid APPid}, if receiver is a 
 * {@link LogicalProcess}, or identifier, if receiver is a monitoring/steering
 * application. */
String receiverAPPid;

/**Receiver's LP number*/
int receiverLP;

/**Receiver's PE number*/
int receiverPE;

/**Receiver's machine name*/
String receiverMN;

/**Preferred constructor; constructs a Message object of undefined origin and 
  *destination.
  *The sender and receiver info must be set later.
  *@param time The local sim time this message occurs.
  *@param typ MsgType of this Message.
  *@param cont Object the content of the message.
  */
public Message(int time, MsgType typ, Object cont)
{
   tag=0; //0=not acknowledged yet
   timeStamp=time;
   msgType=typ;
   content=cont;
   senderAPPid = null;
   senderLP = -1;
   senderPE = -1;
   receiverAPPid = null;
   receiverLP = -1;
   receiverPE = -1;
   receiverMN=null;

}//end constructor


/**Sets the machine name of the receiver of this message.
  *@param mn a String object representing the machine name.
  */
void setReceiverMN(String mn)
{
   receiverMN=mn;
}


/**Returns the machine name of the receive of this message.
  */
public String getReceiverMN()
{
  return receiverMN;
}//end getReceiverMN

/**Constructs a Message object with preliminary (not complete) addressing.
 * senderLP, senderPE, receiverLP, and receiverPE must be specified later!
  *@param time The local sim time this message occurs.
  *@param typ MsgType of this Message. 
  *@param cont Object the content of the message.
  *@param sender String the APPid of the sender LP.
  *@param receiver String the APPid of the receiver LP.
  */
public Message(int time, MsgType typ, Object cont, String sender, 
	String receiver)
{
   timeStamp=time;
   msgType=typ;
   content=cont;
   senderAPPid=sender;
   senderLP = -1;
   senderPE = -1;
   receiverAPPid=receiver;
   receiverLP = -1;
   receiverPE = -1;
}//end constructor

/**Sets the message type;
  *@param typ MsgType
  */
void setMsgType(MsgType typ)
{
   msgType=typ;

}//end setMsgType

/**Returns a copy of the passed-in message with a negative sign.
  */
Message makeAntiMsg()
{
  Message antiMsg=new Message(this.timeStamp, Message.MsgType.SIM_ANTI, this.content, this.senderAPPid, this.receiverAPPid);
  antiMsg.senderLP=this.senderLP;
  antiMsg.senderPE=this.senderPE;
  antiMsg.receiverLP=this.receiverLP;
  antiMsg.receiverPE=this.receiverPE;

  return antiMsg;
}//end makeAntiMsg

/**Returns the PE id of the receiver of the message.
  */
public int getReceiverPE()
{
  return receiverPE;
}//end getsReceiverPE

/**Sets the sender's PE number.
  *@param sPE int the PE where the sender resides.
  */
void setSenderPE(int sPE)
{
   senderPE=sPE;
}//end setSenderPE

/**Sets the sender's LP number.
  *@param sLP int the LP id of the sender.
  */
void setSenderLP(int sLP)
{
   senderLP=sLP;
}//end setSenderLP

/**Sets the receiver's PE number.
  *@param rPE int the PE where the receiver resides.
  */
void setReceiverPE(int rPE)
{
   receiverPE=rPE;
}//end setReceiverPE

/**Sets the receiver's LP number.
  *@param rLP int the id of the receiver LP.
  */
void setReceiverLP(int rLP)
{
   receiverLP=rLP;
}//end setReceiverLP


/**Sets the sender APPid.*/
void setSenderAPPid(String said)
{
   senderAPPid=said;
}//end setsSenderName

/**Sets the receiver APPid.*/
void setReceiverAPPid(String raid)
{
   receiverAPPid=raid;
}//end setsReceiverName

/**gets the receiver LP.*/
public int getReceiverLP()
{
  return receiverLP;
}//end getsReceiverLP

/**gets the sender LP.*/
public int getSenderLP()
{
  return senderLP;
}//end getsSenderLP

/**Returns the sender name.*/
public String getSenderAPPid()
{
   return senderAPPid;
}//end getSenderName

/**Returns the receiver name.*/
public String getReceiverAPPid()
{
  return receiverAPPid;
}//end getReceiverName

/**Returns the type of the message.*/
public MsgType getMsgType()
{
   return msgType;
}

/**Returns the time stamp of the message.*/
public double getTimeStamp()
{
   return timeStamp;
}

/**Returns the content of the message.*/
public Object getContent()
{
   return content;
}


/**Returns a string representation of the Message object.
 */
public String toString()
{
	return "Message of type "+msgType+" with timestamp "+timeStamp+
		" from ("+senderAPPid+","+senderLP+","+senderPE+") to ("+
		receiverAPPid+","+receiverLP+","+receiverPE+") with content "+
		content;
}

/**Compares two Messages' time stamps. If this Message has an earlier time 
 * stamp than the other, it is "less than" it, and a negative number is
 * returned. If this message has a later time stamp, it is "greater" and a 
 * positive number is returned. If they have the same time stamp, zero is
 * returned (marking them as "equal"). As such, note: this class has a natural 
 * ordering that is inconsistent with equals. */
public int compareTo(Message O)
{
	//can't just return (sendTimeStamp - O.sendTimeStamp) due to rounding...
	if (timeStamp < O.timeStamp)
		return -1;
	else if (timeStamp > O.timeStamp)
		return 1;
	return 0;
}

}//end class Message