public enum OrderType
{
    Coop = 0,
    Normal = 1,
    Package = 2,
    SubInvoicing = 3,
}

public enum OrderType
{
    Coop,
    Normal,
    Package,
    SubInvoicing
}

public class OrderTypeMap
{
  private static Map<String, Integer> typeMap = new Map<String, Integer>
  {
    'Coop' => 0,
    'Normal' => 1,
    'Package' => 2,
    'SubInvoicing' => 3
  };

  public Integer Value(String s)
  {
    return typeMap.get(s);
  }
}

Integer i = OrderTypeMap.Value(OrderType.Normal.name());

public class Foo {
    public enum OrderType
    {
        Coop,
        Normal,
        Package,
        SubInvoicing
    }

    public Map<OrderType,Integer> OrderTypeMap = ( new Map<OrderType,Integer>{
        Coop => 1,
        Normal => 2,
        Package => 3,
        SubInvoicing => 4 } );

...
}

public class Foo {
    public static OrderTypeEnum OrderType = new OrderTypeEnum();

    public class OrderTypeEnum
    {
        public Integer Coop { get { return 1; } }
        public Integer Normal { get { return 2; } }
        public Integer Package { get { return 3; } }
        public Integer SubInvoicing { get { return 4; } }
    }

...
}

Foo.OrderType ot = Foo.OrderType.Coop;
if(Foo.OrderTypeMap.get(ot) == 1)
...

Integer ot = Foo.OrderType.Coop;
if(ot == Foo.OrderType.Coop)
...

public class Foo {
    public static OrderTypeEnum OrderType = new OrderTypeEnum(null);

    public class OrderTypeEnum
    {
        public final Integer value;
        OrderTypeEnum(Integer value) { this.value = value; }
        public OrderTypeEnum Coop { get { return new OrderTypeEnum(1); } }
        public OrderTypeEnum Normal { get { return new OrderTypeEnum(2); } }
        public OrderTypeEnum Package { get { return new OrderTypeEnum(3); } }
        public OrderTypeEnum SubInvoicing { get { return new OrderTypEnum(4); } }
        public Boolean equals(Object that) {
            return (that instanceof OrderTypeEnum)?((OrderTypeEnum)that.value == value):(that == value);
        }
        public Integer hashCode() {return value;}
    }

...
}

Foo.OrderTypeEnum ot = Foo.OrderType.Coop;
if(ot == 1)
...
if(ot == Foo.OrderType.Coop)
...