/*
			  CARNEGIE MELLON UNIVERSITY
			    NON-EXCLUSIVE END-USER
			  SOFTWARE LICENSE AGREEMENT

    
				  RETSINA(tm)
    Reusable Environment for Task Structured Intelligent Network Agents(tm)

IMPORTANT: PLEASE READ THIS  SOFTWARE LICENSE AGREEMENT ("AGREEMENT") CAREFULLY.

          LICENSE

The CMU Software, together with  any fonts accompanying this Agreement, whether
on  disk,  in read  only  memory  or  any other  media  or  in any  other  form
(collectively,  the  "CMU Software")  is  never  sold.   It is  non-exclusively
licensed  by Carnegie  Mellon University  ("CMU") to  you solely  for  your own
internal, non-commercial research purposes on the terms of this Agreement.  CMU
retains the ownership of the CMU  Software and any subsequent copies of the CMU
Software. The CMU Software and any copies made under this Agreement are subject
to this Agreement.

          YOU MAY:

          1. LOAD and USE the CMU Software as long as the  CMU Software is only
          used on one (1) computer by one (1) user at a time. This license does
          not allow the CMU Software to exist on more than one (1)  computer at
          a time or on a computer  network,  including  without  limitation  an
          intranet network or a local area network.

          2. USE the CMU Software solely for your own internal,  non-commercial
          research purposes. 

          3. COPY the CMU Software for back-up purposes only. You may make  one
          (1) copy of the CMU Software in  machine-readable  form  for  back-up
	  purposes.  The  back-up  copy  must  contain  all  copyright  notices
	  contained in the original CMU Software.

          4. TERMINATE this Agreement by destroying the original and all copies
          of the CMU Software in whatever form.

          YOU MAY NOT:

          1. Assign, delegate or  otherwise  transfer  the  CMU  Software,  the
	  license (including this Agreement),  or  any  rights  or  obligations
	  hereunder or thereunder, to another person or entity.  Any  purported
	  assignment, delegation or transfer in  violation  of  this  provision
	  shall be void.

          2. Loan, distribute,  rent,  lease,  give,  sublicense  or  otherwise
          transfer the CMU Software (or any copy of the CMU Software), in whole
          or in part, to any other person or entity.

          3. Copy, alter, translate, decompile, disassemble,  reverse  engineer
          or create derivative works from the CMU Software, including  but  not
          limited to, modifying the CMU Software to make  it  operate  on  non-
	  compatible hardware.

          4. Remove, alter or cause not to be displayed, any copyright  notices
          or startup messages contained in the CMU Software.

          5. Export the CMU Software or the product components in violation  of
	  any United States export laws.

Title to the CMU Software,  including the ownership of all copyrights, patents,
trademarks  and  all  other  intellectual  property rights  subsisting  in  the
foregoing, and all  adaptations to and modifications of  the foregoing shall at
all times remain with CMU. CMU  retains all rights not expressly licensed under
this Agreement. The CMU  Software, including any images, graphics, photographs,
animation, video, audio, music and text incorporated therein is owned by CMU or
its  suppliers   and  is  protected   by  United  States  copyright   laws  and
international  treaty provisions.   Except as  otherwise expressly  provided in
this  Agreement,  the copying,  reproduction,  distribution  or preparation  of
derivative works  of the CMU Software  is strictly prohibited by  such laws and
treaty provisions.   Nothing in  this Agreement constitutes  a waiver  of CMU's
rights under United States copyright law.

This Agreement and your rights are  governed by the laws of the Commonwealth of
Pennsylvania.  If  for any reason a  court of competent  jurisdiction finds any
provision  of this  Agreement, or  portion  thereof, to  be unenforceable,  the
remainder of this Agreement shall continue in full force and effect.

THIS LICENSE SHALL TERMINATE AUTOMATICALLY if you fail to comply with the terms
of this Agreement.

          DISCLAIMER OF WARRANTY ON CMU SOFTWARE

You expressly  acknowledge and agree  that your use  of the CMU Software  is at
your sole risk.

THE CMU SOFTWARE IS PROVIDED "AS IS"  AND WITHOUT WARRANTY OF ANY KIND, AND CMU
EXPRESSLY  DISCLAIMS ALL  WARRANTIES, EXPRESS  OR IMPLIED,  INCLUDING,  BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY  RIGHTS.  THE ENTIRE RISK AS TO THE
QUALITY AND PERFORMANCE  OF THE CMU SOFTWARE IS BORNE  BY YOU.  THIS DISCLAIMER
OF WARRANTIES, REMEDIES AND LIABILITY  ARE FUNDAMENTAL ELEMENTS OF THE BASIS OF
THE AGREEMENT BETWEEN  CMU AND YOU.  CMU  WOULD NOT BE ABLE TO  PROVIDE THE CMU
SOFTWARE WITHOUT SUCH LIMITATIONS.

          LIMITATION OF LIABILITY

THE  CMU  SOFTWARE  IS  BEING  PROVIDED  TO  YOU  FREE  OF  CHARGE.   UNDER  NO
CIRCUMSTANCES, INCLUDING  NEGLIGENCE, SHALL CMU  BE LIABLE UNDER ANY  THEORY OR
FOR  ANY  DAMAGES INCLUDING,  WITHOUT  LIMITATION,  DIRECT, INDIRECT,  GENERAL,
SPECIAL, CONSEQUENTIAL, INCIDENTAL, EXEMPLARY  OR OTHER DAMAGES) ARISING OUT OF
THE USE OF OR  INABILITY TO USE THE CMU SOFTWARE OR  OTHERWISE RELATING TO THIS
AGREEMENT (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
BUSINESS  INTERRUPTION, LOSS  OF BUSINESS  INFORMATION OR  ANY  OTHER PECUNIARY
LOSS), EVEN  IF CMU HAS BEEN ADVISED  OF THE POSSIBILITY OF  SUCH DAMAGES. SOME
JURISDICTIONS  DO  NOT ALLOW  THE  EXCLUSION  OR  LIMITATION OF  INCIDENTAL  OR
CONSEQUENTIAL DAMAGES SO THIS LIMITATION MAY NOT APPLY TO YOU.

          ADDITIONAL PROVISIONS YOU SHOULD BE AWARE OF

This Agreement constitutes  the entire agreement between you  and CMU regarding
the CMU  Software and supersedes any prior  representations, understandings and
agreements, either  oral or  written. No amendment  to or modification  of this
Agreement will be binding unless in writing and signed by CMU.

          U.S. GOVERNMENT RESTRICTED RIGHTS

If the CMU Software or any accompanying documentation is used or acquired by or
on behalf of any unit, division or agency of the United States Government, this
provision  applies.  The  CMU Software  and any  accompanying  documentation is
provided with RESTRICTED RIGHTS.  The use, modification, reproduction, release,
display,  duplication  or disclosure  thereof  by or  on  behalf  of any  unit,
division or agency  of the Government is subject to  the restrictions set forth
in  subdivision (c)(1)  of the  Commercial Computer  Software-Restricted Rights
clause at  48 CFR  52.227-19 and the  restrictions set  forth in the  Rights in
Technical   Data-Non-Commercial   Items   clause    set   forth   in   48   CFR
252.227-7013. The contractor/manufacturer of  the CMU Software and accompanying
documentation is  Carnegie Mellon  University, 5000 Forbes  Avenue, Pittsburgh,
Pennsylvania 15213, U.S.A.
*/
/* Copyright (c) 1998, Dirk Kalp, Katia Sycara, RETSINA Project,
                       Carnegie Mellon University
   All rights reserved
*/

/*----------------------------------------------------------------------------
  HISTORY:
    Spring/Summer 1998 Dirk Kalp (kalp@cs.cmu.edu)
    Created the module.

    Dec 03 1998 Dirk Kalp (kalp@cs.cmu.edu)
    Added this HISTORY log. 
----------------------------------------------------------------------------*/

package EDU.cmu.softagents.retsina.Communicator;


/** An InternalMsg is used within an agent. In addition to the AgentMsg
    interface which InternalMsg extends, it can also be used to store
    any variety of internal state, such as the particular communication
    channel internal to the agent used to receive the msg or to be
    used to send the msg. This internal state, while a convenience
    within the agent as it processes a msg, is irrelevant to the
    outside agent. Thus it should be filtered from the msg when it
    is to be sent to the external agent.
*/
public interface InternalMsg extends AgentMsg {
  // Probably these are just internal fields since they serve to
  // define the connection-name and are used to indicate the role,
  // client or server, being played by the agent in the context of
  // of this msg.
  public static final String CLIENT_AGENT = "client";
  public static final String SERVER_AGENT = "server";
  public static final String LOCALPORT = "localport";

  // Strictly a field of an internal msg used to associate this
  // msg to a communication channel in an agent. This field can
  // be used internally to lookup the communication channel from
  // a table. The connection-name will consist of the ordered
  // triple:
  //     
  public static final String CONNECTION_NAME = "connection-name";

  public static final String[] basicInternalFields = {CLIENT_AGENT,
						 SERVER_AGENT,
						 LOCALPORT,
						 CONNECTION_NAME};


  /** Provide a means to transform an InternalMsg to an ExternalMsg so
      that ultimately the msg can be transmitted to an external agent.
      Internal fields such as "connection-name" should be filtered out.
      This method provides the link between ExternalMsgs and InternalMsgs by
      exposing the details of the class used to implement InternaMsg to the
      class implementing ExternalMsg. A corresponding method is in InternalMsg.
      The class that implements the InternalMsg interface will need to
      get an instantiation of the class implementing ExternalMsg in order
      to implement the convertToExternal() method.
  */
  public ExternalMsg convertToExternal();


  // NOTE: Should all the create methods below be static methods? It would 
  //       be nice since they don't operate on this object or create new 
  //       objects based on it. But I can't define static methods in an 
  //       interface and I do want these to be implemented in every 
  //       InternalMsg class. So I have to leave them as instance methods.
  // 

  /** Create a new InternalMsg instance. This will be a simple instance
      with all its fields cleared.
  */
  public InternalMsg createInternalMsg();


  /** Create an InternalMsg from a string representation of an application
      msg protocol object. (In KQML protocol, this would be the String
      representation of a KQMLmessage object.) The application refers to the
      program or agent that has integrated the use of the Communicator into
      itself.
  */
  public InternalMsg createInternalMsg(String applicationMsgProtocolString);


  /** Create an InternalMsg from an object that is an instance of an
      application msg protocol object. (In KQML protocol, this would be
      a KQMLmessage instance.) The application refers to the program or agent
      that has integrated the use of the Communicator into itself.
  */
  public InternalMsg createInternalMsg(Object applicationMsgProtocolObject);


  // NOTE: It would be nice to have this as a static method but I wouldn't
  //       be able to put it in InternalMsg since interfaces can't have
  //       static methods. But I do want it to be in every class that
  //       implements InternalMsg. So I have to keep it as an instance method.
  //
  /** When an agent needs to send a reply msg to an external agent, he
      can use the external agent's msg being replied to in order to
      build the reply msg. The method here assumes that the msg instance
      here is the external agent's msg we want to reply to. So the method
      takes this msg and clones it, swaps sender and receiver, assigns new
      performative and content and reply-with, and sets in-reply-to from
      this msgs's reply-with. The msg built is returned as the reply msg.
  */
  public InternalMsg buildReplyMsg(String performative,
				   String content,
				   String replyWith);

  /** This method overloads buildReplyMsg() to leave the reply-with
      field empty. This is intended for use with Communicator msg send
      methods that fill in the reply-with field to perform synchronized
      communication (with blocking) with the external agent or to establish
      a redirection of msgs from the external agent into a Provision queue.
  */
  public InternalMsg buildReplyMsg(String performative,
				   String content);

}