Encrypted.java

import java.util.*;
public class EncryptedGrid {

	private List<Character> grid = new ArrayList<>();
	private String keyword;

	/**
	 * Constructor of the EncryptedGrid class
	 * @param plaintext - the plaintext we wish to encrypt, already with all lowercase and now punctuation
	 * @param keyword - the keyword, already in all lowercase
	 */
	public EncryptedGrid(String plaintext, String keyword) {
		this.keyword = keyword;

		// calculates length of grid arraylist to be the least multiple of keyword length greater than
		// the cipher text length
		int gridLength = plaintext.length() + keyword.length() - (plaintext.length() % keyword.length());

		for(int i=0; i<plaintext.length(); i++) {
			grid.add(plaintext.charAt(i));
		}

		for(int i=plaintext.length(); i<gridLength; i++) {
			grid.add('x');
		}
	}
}