package jsetool.data;

import java.io.Serializable;

/**
 * @author Mike Lawson
 *
 * As of Oct 20, 2004
 * 
 * The Transition class represents either a SEND or RECEIVE transition
 * in the CFSM diagram.  It is composed of a message.
 * 
 * 
 */
public class Transition implements Serializable
{
  /** Denotes a SEND transition   */
  public static final short SEND = 0;
  
  /** Denotes a RECEIVE transition   */
  public static final short RECEIVE = 1;
  
  /** The transition type - either SEND or RECEIVE */
  protected short transitionType;
  
  /** The message being sent */
  protected String message;
  
  protected MachineState sourceState;
  
  protected MachineState targetState;  
  
  protected boolean explored = false;
  
  /**
   * Constructs a new Transition object
   * @param type the type of transition, either SEND or RECEIVE
   * @param source the state where this transition comes FROM
   * @param targetState the state that this transition goes TO
   * @param message the message associated with the transition
   */
  public Transition(short type, MachineState source, MachineState targetState, String message)
  {
    this.transitionType = type;
    this.message = message;
    this.sourceState = source;
    this.targetState = targetState;
  }

  /**
   * Returns the String representation of this transition as we specified
   * in CS522: -M for sending M, +R for receiving R
   * @return String
   */
  public String toString()
  {
    String modifier = transitionType == SEND ? "-" : "+";
    return modifier + message;
  }
  
  
  /**
   * Returns a more verbose String version of this object.
   * @return String
   */
  public String verboseString()
  {
    return sourceState.getStateName() + " " + toString() + " " + targetState.getStateName();
  }
  
  /**
   * Returns true if this transition has been explored.
   * @return boolean
   */
  public boolean isExplored()
  {
    return explored;
  }
  
  /**
   * Sets this transition as having been explored.
   */
  public void setExplored()
  {
    this.explored = true;
  }
  
  /**
   * @return Returns the message.
   */
  public String getMessage()
  {
    return message;
  }
  
  /**
   * @return Returns the targetState.
   */
  public MachineState getTargetState()
  {
    return targetState;
  }
  
  /**
   * @return Returns the transitionType.
   */
  public short getTransitionType()
  {
    return transitionType;
  }
  
}