@@ -0,0 +1,380 @@
+package src.model;%0A%0Apublic class IdGenorator %7B%0A    private static IdGenorator instance = null;%0A    int next = 0;%0A    protected IdGenorator()%7B%7D%0A    public static IdGenorator getInstance()%7B%0A        if(instance == null)%7B%0A            instance = new IdGenorator();%0A        %7D%0A        return instance;%0A    %7D%0A%0A    public int getNewId()%7B%0A        next++;%0A        return (next - 1);%0A    %7D%0A%7D%0A

Create IdGenorator.java