package de.fesere.tictactoe;

public enum Marker {
    X,
    O,
    NONE;

    public boolean isNone() {
        return this == NONE;
    }

    public boolean isMarked() {
        return !isNone();
    }


    @Override
    public String toString() {
        if(this== X) {
            return "X";
        }
        if(this==O){
            return "O";
        }
        return " ";
    }
}

@@ -200,16 +200,185 @@
 %0A    %7D%0A%0A
+    public Marker other() %7B%0A        if(this == X) %7B%0A            return O;%0A        %7D%0A        if( this == O) %7B%0A            return X;%0A        %7D%0A        return null;%0A    %7D%0A%0A
 %0A    @Ov

Allow the marker to return the opponent Player or null for NONE