//Implementation
//編寫遠程服務的具體實現

import java.rmi.server.UnicastRemoteObject; 
public class CalculatorImpl extends UnicastRemoteObject implements Calculator 
{ 
    // 這個實現必須有一個顯式的構造函數，并且要拋出一個RemoteException異常 
    public CalculatorImpl() 
        throws java.rmi.RemoteException
    { 
        super(); 
    }  
   
    public long add(long a, long b) 
        throws java.rmi.RemoteException
    { 
        return a + b; 
    }
      
    public long sub(long a, long b) 
        throws java.rmi.RemoteException 
    { 
        return a - b; 
    } 
    
    public long mul(long a, long b) 
        throws java.rmi.RemoteException
    { 
        return a * b; 
    } 
 
    public long div(long a, long b) 
        throws java.rmi.RemoteException
    { 
        return a / b; 
    } 
}