/**
@author  Scott Marshall
@author  University of Glasgow, MSc IT Project 2001
@author  Building an OnLine Course in Computing Fundamentals

*/

package ukacgla_ATT;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Vector;


abstract public class Checker{

	/** Allows access to the GUI and student input variables */
	protected TableUI table;	
	
	/** Contains the random numbers corresponding to the type of logic gate */
	protected TTRandom random;		

	/** True if all student input correct, otherwise false */
	protected boolean correct;		

	/** Holds the number of lines containing errors */
	protected Vector wrongLines;
	
	public Checker(TableUI t,TTRandom r){
		table = t;
		random = r;
		wrongLines = new Vector();
	}


	/** Implementations of calcAnswer(int row)  must provide the correct answer for a single row. 	*/
	abstract protected void calcAnswer(int row);
	
	
	/**	Implementations of revealAnswer(int row)  will display the correct answer for a single row.	*/
	abstract protected void revealAnswer(int row);

	
	/** Implementation of checkAnswer(int row) must check if the student input for a single line is correct.*/
	abstract protected void checkAnswer(int row);


	/**	Returns boolean true if no errors found.*/
	protected boolean allCorrect() {

		if (wrongLines.size()==0)
			correct = true;
		else
			correct = false;	
		return correct;
	}
	
	/**
	Vector wrongLines contains the rows with errors. Method returns the vector as a string
	to allow table to construct the appropriate error message
	*/
	protected String wrongLines(){
		return wrongLines.toString();
	}
	
	/** clears contents of vector prior to next checking run. */
	protected void clearVector(){
		wrongLines.clear();
	}
	
	
	
}