//-----------------------------------------------------------------
// CSE 461 Project 1
//
// simulate.java: This describes the interface presented to clients
//                of the simulator.  
//-----------------------------------------------------------------

//-----------------------------------------------------------------
// Address: an address for a node.  This implementation uses
//          arbitrary strings as addresses, and ensures that 
//          they are compared with string comparison.
//-----------------------------------------------------------------
class Address
{
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Constructor: takes the address in string form
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public Address (String s)
   {
      text = s;
   }

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // toString: allows printing of addresses
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public String toString ()
   {
      return text;
   }

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // equals: control comparison of addresses
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public boolean equals (Address rhs)
   {
      return text.equals (rhs.text);
   }

   private String text;
}

//-----------------------------------------------------------------
// Packet: the data carried in a packet.  Feel free to add
//         reasonable stuff here.
//-----------------------------------------------------------------
class Packet
{
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Addresses of the sender and receiver
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public Address sourceAddr;
   public Address destinationAddr;

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Sequence number of this packet
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public int sequenceNum;

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Is this an ack or a regular packet?
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public boolean ack;

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // The data carried by the packet (<= MTU of the link)
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public byte[] data;
}

//-----------------------------------------------------------------
// PacketReceiver: clients who want ot receive packets from links
//                 need to implement this interface
//-----------------------------------------------------------------
interface PacketReceiver 
{
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Callback that a packet has arrived.  Implementations of this
   // need to run in zero simulated time.
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public void PacketArrived (Packet p);
}

//-----------------------------------------------------------------
// Link: the generic interface to a link.  Clients may call these
//       functions on any link.
//-----------------------------------------------------------------
interface Link
{
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Send a packet, blocking until the packet has been transmitted
   // (but not necessarily received).  Threads calling this need
   // to be registered with the timer.
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public void TransmitPacket (Packet p);

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Query the maximum data size of packets on this link
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public int MTU ();

   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   // Add and Remove receivers.  Clients need to identify 
   // themselves using AddReceiver (passing 'this' (since they
   // must implement PacketReceiver) and their address).  
   // RemoveReceiver can be used to stop receiving packets.
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   public void AddReceiver (PacketReceiver rcvr, Address address);
   public void RemoveReceiver (PacketReceiver rcvr);
}