package bvyy.command;
// Copyright(C)1998 Brian Yap

// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.

// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
// more details.

// You should have received a copy of the GNU General Public License along with
// this program; if not, write to the Free Software Foundation, Inc., 675 Mass
// Ave, Cambridge, MA 02139, USA.
import bvyy.util.GeneralEvent;
/**
 * All commands are types of general events. This allows them to be transported
 * across the model using the listener interfaces in addition to the RMI and
 * data bus transport.</P>
 *
 * As you can see the commands closely match the Java beans standard commands
 * and those used by Sun generally inside Java. This is deliberate. There needs
 * to be a 1:1 mapping between these commands and their implementation inside
 * the objects and beans. This will greatly add to readability and reliability.
 * </P>
 *
 * A command has an ordered set of argument objects. Initially these objects
 * are sent by the user interface. Latter in the processing of the command,
 * these objects are replaced with the actual database objects where the
 * command action is processed.
 *
 * @version 0.0.1  27 October 1998
 * @author (c)1998 Brian Voon Yee Yap
 */

public abstract class Command extends GeneralEvent{

  private java.util.Hashtable arguments;
/**
 * Creates a new command.
 */
  public Command(){
    super();
  }
/**
 * Creates a new command with a description of S.
 *
 * @param s the event description.
 */
  public Command(String S) {
    super(S);
  }
/**
 * execure this command.
 *
 * @param arguments This is a hash table of the arguments.
 */
  public abstract void execute(java.util.Hashtable theArguments)
         throws CommandCompletelyFailedException,
                CommandPartlyFailedException;
/**
 * Returns the current command arguments list. The command arguments list is
 * a vector and this allows modification this list using the normal vector
 * functions.</P>
 *
 * For example: comand.getArguments.addElement(ArgumentX);</P>
 *
 * @see java.util.vector
 */
  public java.util.Hashtable getArguments() {
    return arguments;
  }
/**
 * Allows replacement of the current command argument list with a new command
 * argument list. All current arguments are lost.</P>
 *
 * Note: The command comes with it's own command srgument list so it will not
 * normally be necessary to call this function.</P>
 *
 * It a null command srgument list is supplied it will be ignored.
 *
 * @param newArguments the list that replaces the current list.
 */
  public void setArguments(java.util.Hashtable  newArguments) {
    arguments = newArguments;
  }
}