命令模式（2）-命令接口中的撤销方法

通过封装请求的execute()方法以及撤销请求的undo()方法：

接受者：
package DesignPatterns.CommandMode1;

import java.lang.reflect.Array;
import java.util.ArrayList;

public class StringReceiver {
    public void printString(ArrayList<String> arrayList)
    {
        System.out.println("输出后");
        for (int i=0;i<arrayList.size();i++)
        {
            System.out.println(arrayList.get(i));
        }
    }
    public void cancelString(ArrayList<String> arrayList)
    {
        System.out.println("取消输出后");
        for (int i=0;i<arrayList.size();i++)
        {
            System.out.println(arrayList.get(i));
        }

    }
}

命令接口：

package DesignPatterns.CommandMode1;

import java.util.ArrayList;

public interface StringCommand {
    void execute(String name);
    void undo(String name);
}


具体命令：

package DesignPatterns.CommandMode1;

import java.util.ArrayList;

public class StringConcreteCommand  implements StringCommand{
    ArrayList<String> arrayList;
    StringReceiver stringReceiver;
    public StringConcreteCommand(StringReceiver stringReceiver)
    {
        this.arrayList=new ArrayList<>();
        this.stringReceiver=stringReceiver;
    }
    @Override
    public void execute(String name) {
        arrayList.add(name);
        stringReceiver.printString(arrayList);
    }

    @Override
    public void undo(String name) {
        arrayList.remove(name);
        stringReceiver.cancelString(arrayList);

    }
}


请求者：

package DesignPatterns.CommandMode1;

import DesignPatterns.CommandMode.Command;

public class StringInvoker {
    StringCommand stringCommand;
    String name;

    public void setName(String name) {
        this.name = name;
    }

    public void setStringCommand(StringCommand stringCommand)
    {
        this.stringCommand=stringCommand;
    }
    public void executeStringCommand()
    {
        stringCommand.execute(name);
    }
    public void undoStringCommand()
    {
        stringCommand.undo(name);
    }
}


测试类：

package DesignPatterns.CommandMode1;

public class Application {
    public static void main(String[] args) {
        StringReceiver stringReceiver=new StringReceiver();
        StringCommand stringCommand=new StringConcreteCommand(stringReceiver);
        StringInvoker stringInvoker=new StringInvoker();
        stringInvoker.setStringCommand(stringCommand);
        stringInvoker.setName("xujinfeng");
        stringInvoker.executeStringCommand();
        stringInvoker.undoStringCommand();
    }
}