命令模式实现简单计算器功能包括撤销

考虑一个计算器功能，只能实现加法和减法运算。但是，这个计算器支持撤销操作。

package Command;

public class AddCommandImpl implements CommandInterface{
	private OperationsInterface operation = null;
	private int number;
	
	public AddCommandImpl（OperationsInterface operationint number） {
		// TODO Auto-generated constructor stub
		this.operation = operation;
		this.number = number;
	}
	@Override
	public void Execute（） {
		// TODO Auto-generated method stub
		this.operation.add（number）;
	}

	@Override
	public void Undo（） {
		// TODO Auto-generated method stub
		this.operation.sub（number）;
	}

}

 属性            大小     日期    时间   名称
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     文件        301  2017-12-21 15:26  CommandImpl\.classpath

     文件        387  2017-12-21 15:26  CommandImpl\.project

     文件        598  2017-12-21 15:26  CommandImpl\.settings\org.eclipse.jdt.core.prefs

     文件        732  2017-12-21 15:40  CommandImpl\bin\Command\AddCommandImpl.class

     文件       1699  2017-12-21 17:24  CommandImpl\bin\Command\Calculator.class

     文件        160  2017-12-21 15:36  CommandImpl\bin\Command\CommandInterface.class

     文件       1690  2017-12-21 17:26  CommandImpl\bin\Command\CommandTest.class

     文件        706  2017-12-21 15:34  CommandImpl\bin\Command\OperationsImpl.class

     文件        208  2017-12-21 15:32  CommandImpl\bin\Command\OperationsInterface.class

     文件        732  2017-12-21 17:26  CommandImpl\bin\Command\SubCommandImpl.class

     文件        548  2017-12-21 15:40  CommandImpl\src\Command\AddCommandImpl.java

     文件       1024  2017-12-21 17:24  CommandImpl\src\Command\Calculator.java

     文件         95  2017-12-21 15:36  CommandImpl\src\Command\CommandInterface.java

     文件        885  2017-12-21 17:25  CommandImpl\src\Command\CommandTest.java

     文件        544  2017-12-21 15:34  CommandImpl\src\Command\OperationsImpl.java

     文件        162  2017-12-21 15:32  CommandImpl\src\Command\OperationsInterface.java

     文件        547  2017-12-21 17:26  CommandImpl\src\Command\SubCommandImpl.java

     目录          0  2017-12-21 17:29  CommandImpl\bin\Command

     目录          0  2017-12-21 17:29  CommandImpl\src\Command

     目录          0  2017-12-21 17:29  CommandImpl\.settings

     目录          0  2017-12-21 17:29  CommandImpl\bin

     目录          0  2017-12-21 17:29  CommandImpl\src

     目录          0  2017-12-21 17:29  CommandImpl

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