public interface IChargeWay
{
    ChargeResult doCharge(IChargeEvent event);
}

public class SMChargeWay implements IChargeWay
{
    public ChargeResult doCharge(IChargeEvent event)
    {
        // not supported IChargeEvent subclass will come to this overload method.
        System.out.println("no supported charge event.");
    }

    public ChargeResult doCharge(DownToneEvent event)
    {
        // DownToneEvent charge
        System.out.println("DownToneEvent charge process.");
    }

    ... more overload method for IChargeEvent subclass
}

public interface IChargeEvent
{
    ChargeResult chargeBy(IChargeWay way);
}

public class DownToneEvent implements IChargeEvent
{
    public ChargeResult chargeBy(IChargeWay way)
    {
        return way.doCharge(this);
    }
}

public class CopyToneEvent implements IChargeEvent
{
    public ChargeResult chargeBy(IChargeWay way)
    {
        return way.doCharge(this);
    }
}

public class Test
{
    public static void main(String[] args)
    {
        IChargeEvent dtEvent = new DownToneEvent();
        IChargeWay smWay = new SMChargeWay();
        
        // I expect the following method printing "DownToneEvent charge process."
        // But actually, it prints "no supported charge event."
        dtEvent.chargeBy(smWay);
    }
}