c#interface segregation原理示例混淆

http://www.objectmentor.com/resources/articles/isp.pdf

基本上,它从一个不抱怨ISP(接口隔离原理)的设计开始,然后继续将行为重构为不同的接口.

我的问题是：我们不是使用接口来表达不相关(或不相关)抽象中的共同行为吗？

在接口中封装方法有什么意义,如果不是一个将与将要实现它们的类共享？在哪种情况下,这可能被认为是有用的？

如果我们继续该示例的行,则给出以下代码：

public interface ITransaction
{
    void Execute();
}

public interface IDepositUi
{
    void RequestDepositAmount();
}

public class DepositTransaction : ITransaction
{
    private IDepositUi depositUI;

    public DepositTransaction(IDepositUi ui)
    {
        depositUI = ui;
    }

    public virtual void Execute()
    {
        /*code*/
        depositUI.RequestDepositAmount();
        /*code*/
    }
}

public interface WithdrawalUI
{
    void RequestWithdrawalAmount();
}

public class WithdrawalTransaction : ITransaction
{
    private WithdrawalUI withdrawalUI;

    public WithdrawalTransaction(WithdrawalUI ui)
    {
        withdrawalUI = ui;
    }

    public virtual void Execute()
    {
        /*code*/
        withdrawalUI.RequestWithdrawalAmount(); /*code*/
    }
}

public interface TransferUI
{
    void RequestTransferAmount();
}

public class TransferTransaction : ITransaction
{
    private TransferUI transferUI;

    public TransferTransaction(TransferUI ui)
    {
        transferUI = ui;
    }

    public virtual void Execute()
    {
        /*code*/
        transferUI.RequestTransferAmount();
        /*code*/
    }
}

public interface UI : IDepositUi,WithdrawalUI,TransferUI
{
}

据我所知,为了使用以前的设计,我们应该有类似的东西：

UI impui = new IMPLEMENTATIONUI(); // Some UI implementation
DepositTransaction dt = new DepositTransaction(Gui);
dt.Execute();

现在,我们不需要IMPLEMENTATIONUI实现每一种方法吗？如果是这样,它不会打破SRP吗？