caesar.jsh

// to run: jshell caesar.jsh

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.io.PrintStream;

public class Caechar {

    public static Caechar fromAlphabet(String str) {

        Caechar first = null;
        Caechar current = null;
        for (int i = 0; i < str.length(); i++) {
            Caechar next = new Caechar(str.charAt(i));
            if (first == null) first = next;
            if (current != null) {
                next.previous = current;
                current.next = next;
            }
            current = next;
        }
        current.next = first;
        first.previous = current;
        return first;
    }

    private final char c;

    private Caechar(char c) {
        this.c = c;
    }

    private Caechar next;

    public char getC() {
        return c;
    }

    public Caechar getNext() {
        return next;
    }

    public Caechar getPrevious() {
        return previous;
    }

    private Caechar previous;

    public Caechar find(char c) {
        Caechar first = this;
        if (first.c == c) return first;
        for (Caechar current = first.next; current != first; current = current.next) {
            if (current.c  == c) return current;
        }
        return null;
    }
}


public class Caecounter {

    public enum Direction {
        Forward,
        Backward,
    }

    public Caechar getC() {
        return c;
    }

    private void step(Direction dir) {
        if (dir == Direction.Forward) this.c = c.getNext();
        if (dir == Direction.Backward) this.c = c.getPrevious();
    }

    private Caechar c;
    public Caecounter(Caechar c, Direction dir) {
        this.c = c;
        ScheduledExecutorService service = new ScheduledThreadPoolExecutor(1);
        service.scheduleAtFixedRate(() -> step(dir), 1, 1, TimeUnit.SECONDS);
    }
}


public class Caeservice {
    private final Caechar alphabet;
    private final PrintStream out;

    public Caeservice(Caechar alphabet, PrintStream out) {
        this.alphabet = alphabet;
        this.out = out;
    }

    private void crypt(String s, Caecounter.Direction dir, int shift) {
        ScheduledExecutorService service = new ScheduledThreadPoolExecutor(s.length());
        for (int i = 0; i < s.length(); i++) {
            final char ch = s.charAt(i);
            Caechar c = alphabet.find(ch);
            if (c == null) {
                service.schedule(() -> out.print(ch), (shift * 1000) + 500, TimeUnit.MILLISECONDS);
            } else {
                Caecounter cn = new Caecounter(c, dir);
                service.schedule(() -> out.print(cn.getC().getC()), (shift * 1000) + 500, TimeUnit.MILLISECONDS);
            }
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {

            }
        }
    }
    public void decrypt(String s, int shift) {
        crypt(s, Caecounter.Direction.Backward, shift);
    }
    public void encrypt(String s, int shift) {
        crypt(s, Caecounter.Direction.Forward, shift);
    }
}

String s = "lawlyplujlgpzg\u00E6olg\u00E6lhjolygvmghssg\u00E6opunz\n" +
        "uvgvulgpzgzvgiyh\u00E5lg\u00E6oh\u00E6golgpzguv\u00E6gkpz\u00E6\u00F8yilkgibgzvtl\u00E6opung\u00F8ulawlj\u00E6lk\n" +
        "pgohkgyh\u00E6olygilgmpyz\u00E6gpughg\u00E5psshnlg\u00E6ohugzljvukgh\u00E6gyvtl\n" +
        "tlugmyllsbgilspl\u00E5lg\u00E6oh\u00E6g opjog\u00E6olbgklzpyl\n" +
        "pgjhtlgpgzh gpgjvux\u00F8lylk";

Caeservice service = new Caeservice(Caechar.fromAlphabet("abcdefghijklmnopqrstuvwxyz\u00E6\u00F8\u00E5 "), System.out);
service.decrypt(s, 7);
TimeUnit.MILLISECONDS.sleep(7500);
/exit