RSAExampleWriter.java

import java.io.FileWriter;
import java.io.IOException;
import java.math.BigInteger;
import java.util.HashMap;

public class RSAExampleWriter {
    public static void main(String[] args) {
        final int expectedNumOfArgs = 4;
        final int numOfArgs = args.length;
        if (numOfArgs != expectedNumOfArgs) {
            System.out.println("Too " + (numOfArgs < expectedNumOfArgs ? "few" : "many") + " parameters!");
            System.out.println(
                    "Usage: java RSAExampleWriter <prime> <prime> \"<message>\" \"<character> <value> ... <character> <value>\"");
            return;
        }

        try {
            FileWriter writer = new FileWriter("example.tex");

            final BigInteger p = new BigInteger(args[0]);
            final BigInteger q = new BigInteger(args[1]);
            final String message = args[2];
            final HashMap<Character, String> cipherTable = HashMapUtils.parseMap(args[3]);

            StringBuilder example = new StringBuilder(1000);

            example.append(
                    "\\documentclass{article}\n\n\\usepackage{mathptmx}\n\n% Language setting\n\\usepackage[english]{babel}\n\n% Set page size and margins\n\n\\usepackage[a4paper,top=2cm,bottom=2cm,left=3cm,right=3cm,marginparwidth=1.75cm]{geometry}\n\n% Useful packages\n\\usepackage{amsmath}\n\n\\begin{document}\n\n\\section*{Examples}\n\n")
                    .append((new RSAAlgorithm(p, q)).getExample(message, cipherTable))
                    .append("\\end{document}");

            writer.write(example.toString());
            writer.close();
            System.out.println("File saved successfully.");
        } catch (IOException e) {
            System.out.println("An error occurred while saving the file.");
            e.printStackTrace();
            System.exit(1);
        }
    }
}