Create check digit for 11 string upc -> 12 string upc

/**
 * Created by Benjamin Ehlers on 12/18/2018 for java.
 * Ported by Larry Stanfield on 2/28/2020 for cfscript.
 * This class evaulates the upc, and in the case of 11 digits it will generate a check digit for it.
 * Also corrected the way it was calculated on the check digit at the end.
 */

component displayname='CheckDigits' output=true hint='A collection of methods used to match items in eclipse.'{

    //Strings
    this.code = true;

    public void function init(required string code) {

        this.code = code;

    }

    public boolean function evaluateValidity( string code ) {

        //boolean
        var valid = false;

        //numerics
        var i           = 1;
        var j           = 2;
        var sumOne      = 0;
        var stepTwo     = 0;
        var sumTwo      = 0;
        var stepFour    = 0;
        var checkDigit  = 0;

        //String
        var currentChar         = '';
        variables.code          = arguments.code?:this.code;

        local.code          = listToArray( duplicate( variables.code ), "" );

        for( i; i < 12; i++ ) {

            if( i == 1 || i % 2 ){

                sumOne          +=   javaCast( 'int', local.code[i] );

            }

        }

        stepTwo = sumOne * 3;
        sumTwo = 0;

        for( j; j < 12; j++ ) {

            if( j % 2 == 0 ){

                sumTwo          += javaCast( 'int', local.code[j] );

            }

        }

            stepTwo += sumTwo;
            stepFour = stepTwo % 10;
            checkDigit = 0;

        if( stepFour != 0 ) {

            checkDigit = 10 - stepFour;

        }

        if( arrayLen( local.code ) == 12  && checkDigit == local.code[ 12 ] ) {

            valid = true;

        }

        return valid;

    }

    public string function generateDigit( string code ) {

        //boolean
        var valid = false;

        //numerics
        var i           = 1;
        var j           = 2;
        var sumOne      = 0;
        var stepTwo     = 0;
        var sumTwo      = 0;
        var stepFour    = 0;
        var checkDigit  = 0;

        //String
        var currentChar         = '';
        variables.code          = arguments.code?:this.code;

        local.code          = listToArray( variables.code, "" );

        for( i; i <= 11; i++ ) {

            if( i == 1 || i % 2 ){

                sumOne          +=   javaCast( 'int', local.code[i] );

            }

        }

        stepTwo = sumOne * 3;
        sumTwo = 0;

        for( j = 2; j <= 11; j++ ) {

            if( j % 2  == 0 ){
                sumTwo          += javaCast( 'int', local.code[j] );
            }

        }

            stepTwo += sumTwo;
            stepFour = stepTwo % 10;
            checkDigit = 0;

        if( stepFour != 0 ) {

            checkDigit = 10 - stepFour;

        }

        return checkDigit;



    }



}