分布计算 实验4(共6页)

1、福州大学数学(shxu)与计算机科学学院上机实验报告专业和班级信息数学02班姓名詹小青成绩课程名称分布计算实验名称使用RMI实现Agent实验目的和要求 1、实验目的： （1）学习派生类的定义和使用； （2）理解派生类对基类成员的访问权 （3）理解派生类的构造函数与析构函数的定义与执行过程； （4）学习多继承类的定义和使用 2、实验要求： （1）定义一个派生类，并且创建该类的对象。 （2）体现出派生类构造函数与析构函数的调用。 （3）理解派生类的构造函数与析构函数的运行顺序。 （4）定义一个多继承的派生类，并且创建该类的对象。 实验内容和步骤1.实验内容：任务1. 根据agent示例目录中re

2、adme文件的说明，运行图8.8到8.12所描述的移动agent演示。描述并解释结果。任务2. 考虑下面所列的应用。描述怎样才能将这些范型(消息队列系统，移动agent和对象空间)应用到这些应用系统中。注意，本题不要求提供具体实现。你的描述应根据范型来分段，而不是根据特定的API。考虑的应用是：a. 监视通过运输工具运输到仓库和商店的货物b. 聊天室c. 在线拍卖d. 使你所在的大学向学生提供课程信息的服务。信息不断更新。2.实验基本步骤：（1）程序：AgentInterface程序：/ An interface for a transportable object /reprsenting

3、a mobile agentimport java.io.Serializable;public interface AgentInterface extends Serializable void execute(); Agent程序： /An implementation of a mobile agent import java.io.*; import java.util.*; import java.rmi.*; import java.rmi.registry.Registry; import java.rmi.registry.LocateRegistry; public cla

4、ss Agent implements AgentInterface int hostIndex; /which host to vist next String name;Vector hostList; /the itineararyint RMIPort=12345; public Agent(String myName,Vector theHostList,int theRMIPort) name=myName; hostList=theHostList; hostIndex=0; RMIPort=theRMIPort;/This method defines the tasks th

5、at the mobile agent is to perform once it has arrived at a server. public void execute() String thisHost,nextHost; sleep(2); /delay for visibility System.out.println(007 here!); thisHost=(String) hostList.elementAt(hostIndex); hostIndex+; if (hostIndexhostList.size() /if there is another host to vis

6、it nextHost=(String) hostList.elementAt(hostIndex); sleep(5); /delay for visibility try / Locate the RMI registry on the next host Registry registry=LocateRegistry.getRegistry(localhost,RMIPort); ServerInterface h=(ServerInterface) registry.lookup(nextHost); System.out.println(Lookup for +nextHost+

7、at +thisHost+ completed ); sleep(5); /Ask the server at the next host to receive this agent h.receive(this); /end try catch (Exception e) System.out.println(Exception in Agent execute: +e); /end if else /if all the stops have been made sleep(5); /delay for visibility System.out.println(Agent 007 has

8、 come home); sleep(5); /delay for 5 visibility / Method sleep suspends this objects execution for the specified number of seconds.static void sleep(double time) try Thread.sleep(long)(time*1000.0); catch (InterruptedException e) System.out.println(sleep exception); /end sleep /end class AgentServerI

9、nterface程序：/ An interface for a transportable object/ representing a mobile agent./M. Liuimport java.io.Serializable;public interface ServerInterface extends Serializable public void receive(Agent h) ;Server程序： import java.io.*;import .*;import java.rmi.*;import java.rmi.server.*;import java.rmi.reg

10、istry.Registry;import java.rmi.registry.LocateRegistry;public class Server static int RMIPort = 12345; String myName; public Server() throws RemoteException super(); public void receive(Agent h)throws RemoteException sleep(3); myName = ; System.out.println(Agent ++ arrived.); h.execute()

11、; public static void main(String args) InputStreamReader is = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(is); try System.setSecurityManager(new RMISecurityManager(); Server h = new Server(); Registry registry = LocateRegistry.getRegistry(RMIPort); registry.rebind(myName

12、, registry); System.out.println(Agent +myName+ready.); catch(RemoteException e) System.out.println(Exception occured in AgentServer.main: +e); private static void sleep(int time) try Thread.sleep(time*1000); catch(InterruptedException e) System.out.println(sleep exception.); Client程序：/Client.java -c

13、lient program for lauching the mobile agent/M. Liu import java.io.*; import java.util.*; import java.rmi.*; import java.rmi.registry.Registry; import java.rmi.registry.LocateRegistry; public class Client static int RMIPort=12345; public static void main(String args) System.setSecurityManager(new RMI

14、SecurityManager(); try Registry registry=LocateRegistry.getRegistry(localhost,RMIPort); ServerInterface h=(ServerInterface) registry.lookup(server1); System.out.println(Lookup for server1 completed ); System.out.println(*Have a good trip,+ agent 007.); Vector hostList=new Vector(); hostList.addEleme

15、nt(server1); hostList.addElement(server2); hostList.addElement(server3); Agent a=new Agent(007,hostList,RMIPort); h.receive(a); System.out.println(*Nice job,agent 007); catch (Exception e) System.out.println(Exception in main:+e); /end main / end class（2）实验结果截图：研究与探讨考虑下面所列的应用。描述怎样才能将消息队列系统，移动agent和对象空间这些范型应用到这些应用系统中。考虑的应用是：a. 监视通过运输工具运输到仓库和商店的货物b. 聊天室c. 在线拍卖d. 使你所在的大学向学生提供课程信息的服务。信息不断更新。答：（1）监视通过运输工具运输到仓库和商店的货物。用消息队列系统实现