Command Pattern (6)
命令模式：
将请求封装为对象，使得客户可以将不同的请求当做参数使用，同时可以支持Undo操作。
示例代码：
using System;
using System.Text;
using System.IO;
namespace Hello
{
//Interface Command
public interface Command
{
void Execute();
void Undo();
}
//No Command
public class NoCommand : Command
{
public void Execute()
{
}
public void Undo()
{
}
}
//Light Class
public class Light
{
public void On()
{
Console.WriteLine("Light is on");
}
public void Off()
{
Console.WriteLine("Light is off");
}
}
//Light On Command
public class LightOnCommand : Command
{
Light light;
public LightOnCommand(Light light)
{
this.light = light;
}
public void Execute()
{
light.On();
}
public void Undo()
{
light.Off();
}
}
//Light Off Command
public class LightOffCommand : Command
{
Light light;
public LightOffCommand(Light light)
{
this.light = light;
}
public void Execute()
{
light.Off();
}
public void Undo()
{
light.On();
}
}
//RemoteControl
public class RemoteControl
{
Command[] onCommands;
Command[] offCommands;
Command undoCommand;
public RemoteControl()
{
onCommands = new Command[7];
offCommands = new Command[7];
Command noCommand = new NoCommand();
for (int i = 0; i < 7; i++)
{
onCommands[i] = noCommand;
offCommands[i] = noCommand;
}
undoCommand = new NoCommand();
}
public void SetCommand(int slot, Command onCommand, Command offCommand)
{
onCommands[slot] = onCommand;
offCommands[slot] = offCommand;
}
public void OnButtonWasPushed(int slot)
{
onCommands[slot].Execute();
undoCommand = onCommands[slot];
}
public void OffButtonWasPushed(int slot)
{
offCommands[slot].Execute();
undoCommand = offCommands[slot];
}
public void UndoButtonWasPushed()
{
undoCommand.Undo();
}
public override string ToString()
{
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.Append("-----Remote Control-----\n");
for (int i = 0; i < onCommands.Length; i++)
{
stringBuilder.Append("[slot" + i + "] " + onCommands[i].ToString()
+ " " + offCommands[i].ToString() + "\n");
}
return stringBuilder.ToString();
}
}
class Program
{
static void Main(string[] args)
{
RemoteControl remoteControl = new RemoteControl();
Console.WriteLine(remoteControl);
Light light = new Light();
LightOnCommand lightOnCommand = new LightOnCommand(light);
LightOffCommand lightOffCommand = new LightOffCommand(light);
remoteControl.SetCommand(3, lightOnCommand, lightOffCommand);
remoteControl.OnButtonWasPushed(3);
remoteControl.OffButtonWasPushed(3);
remoteControl.UndoButtonWasPushed();
Console.WriteLine(remoteControl);
remoteControl.OnButtonWasPushed(0);
remoteControl.OffButtonWasPushed(0);
}
}
}
