package jsetool.data;

import java.io.Serializable;
import java.util.NoSuchElementException;
import java.util.Vector;
import jsetool.data.*;

/** 
 * This class contains information about a single machine, including
 * it's state and it's communication channel.
 * 
 * @author Mike Lawson
 *
 */
public class ExplorationStateContainer implements Serializable
{
  protected MachineState machineState;
  protected Vector communicationChannel = new Vector(); // contains the messages for m1 at this stage
  protected int channelMaxSize = 0; // The maximum size the communication channel ever obtained.

  /**
   * Default constructor
   * 
   */
  public ExplorationStateContainer()
  {
    
  }
  
  /**
   * Copy constructor
   * @param other
   */
  public ExplorationStateContainer(ExplorationStateContainer other)
  {
    this.machineState         = other.getMachineState();
    this.communicationChannel = new Vector(other.getCommunicationChannel());
    this.channelMaxSize       = other.getChannelMaxSize();
  }
  
  /**
   * @return Returns the machineState.
   */
  public MachineState getMachineState()
  {
    return machineState;
  }
  /**
   * @param machineState The machineState to set.
   */
  public void setMachineState(MachineState machineState)
  {
    this.machineState = machineState;
  }
  /**
   * @return Returns the communicationChannel.
   */
  public Vector getCommunicationChannel()
  {
    return communicationChannel;
  }
  
  /**
   * Appends the given message to the channel.
   *  
   * @param message
   */
  public void appendMessage(String message)
  {
    communicationChannel.add(message);
    
    // Keep track of the maximum size of the channel.
    if (communicationChannel.size() > channelMaxSize)
    {
      channelMaxSize = communicationChannel.size();
    }
  }
     
  /**
   * Takes a peek at the first message in the communications channel.
   * @return String
   */
  public String peekFirstMessage()
  {
    try 
    {
      return (String)communicationChannel.firstElement();
    } 
    catch (NoSuchElementException n)
    {
      return null;
    }
  }
  
  /**
   * Returns the maximum size of the communication channel.
   * @return int
   */
  public int getChannelMaxSize()
  {
    return channelMaxSize;
  }

  /** 
   * Returns true of the other object is equal to this one, based
   * on the state and the communication channel.
   * @param obj - the other object to compare
   * @return boolean
   */
  public boolean equals(Object obj)
  {
    
    if (! (obj instanceof ExplorationStateContainer))
    {
      return false;
    }
    
    ExplorationStateContainer other = (ExplorationStateContainer)obj;
    
    // equality is based on both machines being in the same state
    // and the values in the communication channels are exactly the same.
    if (! machineState.equals(other.getMachineState()))
    {
      return false;
    }
          
    if (communicationChannel.equals(other.getCommunicationChannel()))
    {
      return true;
    }
    else
    {
      return false;
    }      
         
  } 
  
  /**
   * Returns a hash for this object
   * @return int
   */
  public int hashCode()
  {
    int cornedBeef = 37;
    cornedBeef ^= machineState.hashCode(); 
    cornedBeef ^= 37 * communicationChannel.hashCode();
    return cornedBeef;
  }
}