/*
 *  JFLAP - Formal Languages and Automata Package
 * 
 * 
 *  Susan H. Rodger
 *  Computer Science Department
 *  Duke University
 *  August 27, 2009

 *  Copyright (c) 2002-2009
 *  All rights reserved.

 *  JFLAP is open source software. Please see the LICENSE for terms.
 *
 */





package automata.mealy;

import automata.Configuration;
import automata.State;

/**
 * A <code>MealyConfiguration</code> object is a <code>Configuration</code>
 * object with an additional field for the input string and the output string.
 * The output is saved as a separate field that is passed in through the
 * constructor. All additional output appended to the output passed in.
 * A <code>MealyConfiguration</code> serves both the 
 * {@link automata.mealy.MealyMachine} and the {@link automata.mealy.MooreMachine}
 * 
 * @author Jinghui Lim
 *
 */
public class MealyConfiguration extends Configuration 
{
    /**
     * The total input.
     */
    private String myInput = "";
    /**
     * The unprocesed input.
     */
    private String myUnprocessedInput = "";
    /**
     * The processed output.
     */
    private String myOutput = "";
    
    /**
     * Constructs a new <code>MealyConfiguration</code>.
     * 
     * @param state the state that the MealyMachine is currently in
     * @param parent the configuration that is the parent of this configuration
     * @param input the entire test input
     * @param unprocessed the unprocessed input
     * @param output the ouput produced before this configuration
     */
    public MealyConfiguration(State state, MealyConfiguration parent, 
            String input, String unprocessed, String output) 
    {
        super(state, parent);
        myInput = input;
        myUnprocessedInput = unprocessed;
        myOutput = output;
    }
    
    /**
     * Returns the total input.
     * 
     * @return total input
     */
    public String getInput()
    {
        return myInput;
    }
    
    /**
     * Returns the unprocessed input.
     * 
     * @return unprocessed input
     */
    public String getUnprocessedInput()
    {
        return myUnprocessedInput;
    }
    
    /**
     * Returns the output produced by previous ancestor configurations.
     * This is the only way to obtain the output produced by a Mealy
     * machine, as <code>Configuration.isAccept()</code> returns a
     * <code>boolean</code>.
     * 
     * @return output by ancestor configurations.
     */
    public String getOutput()
    {
        return myOutput;
    }
    
    /**
     * Changes the unprocessed input.
     * 
     * @param input the string that will replace the unprocessed input
     */
    public void setUnprocessedInput(String input)
    {
        myUnprocessedInput = input;
    }
    
    /**
     * Returns a string representation of this configuration.
     * 
     * @return string representation of this configuration.
     */
    public String toString()
    {
        return super.toString() + ": " + getUnprocessedInput() + "--" + getOutput();
    }

    /**
     * Accepts if there is no more unprocessed input (all of the input has been
     * process and output generated).
     * 
     * @return <code>true</code> if all input has been processed, 
     * <code>false</code> otherwise.
     */
    public boolean isAccept() 
    {
        return getUnprocessedInput().length() == 0;
    }
    
    /**
     * This function checks if two configurations are equal. Two configurations 
     * are equal if they have the same output and unprocessed input and satisfy
     * the <code>.equals()</code> test of the base <code>Configuration</code>
     * class. 
     * 
     * @see automata.Configuration#equals(Object)
     * @param configuration the configuration to check for equality
     * @return <code>true</code> if the two configurations are equal,
     * <code>false</code> otherwise
     */
    public boolean equals(Object configuration)
    {
        if(configuration == this)
            return true;
        try
        {
            MealyConfiguration config = (MealyConfiguration) configuration;
            return super.equals(config) && 
                myUnprocessedInput.equals(config.myUnprocessedInput) &&
                myOutput.equals(config.myOutput);
        }
        catch(ClassCastException e)
        {
            return false;
        }
    }

    /**
     * Returns a hashcode for this object.
     * 
     * @return hashcode for this object
     */
    public int hashCode()
    {
        return super.hashCode() ^ myUnprocessedInput.hashCode() ^ myOutput.hashCode();
    }
}