组件化开发方法
一．题目分析
题目1.Java版CORBA程序1——HelloWorld
1.组件实现
实现详解：
1 编写IDL接口HelloWorld.idl：
module sample{
interface HelloWorld{
wstring sayHello();
};
};
2编译IDL接口：E:\work >idlj –fall HelloWorld.idl
编译结果生成sample包，生成下述文件
_HelloWorldStub.java
HelloWorld.java
HelloWorldHelper.java
HelloWorldHolder.java
HelloWorldOperations.java
HelloWorldPOA.java
3 编写并编译服务端程序:HelloWorldServer.java
import sample.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import org.omg.CORBA.portable.*;
import org.omg.PortableServer.*;
class HelloWorldServant extends HelloWorldPOA{ //对象实现类
public String sayHello(){
return "\nHello World! 软工1704班 张佳欣 \n";
}
}
public class HelloWorldServer{ //服务程序
public static void main(String args[]){
try{
//初始化ORB
ORB orb = ORB.init(args, null);
//取根POA的引用
org.omg.CORBA.Object poaobj = orb.resolve_initial_references ("RootPOA");
org.omg.PortableServer.POA rootPOA = org.omg.PortableServer.POAHelper.narrow(poaobj);
org.omg.PortableServer.POAManager manager = rootPOA.the_POAManager();
//创建伺服对象
HelloWorldServant objRef = new HelloWorldServant();
HelloWorld obj = objRef._this(orb);
//绑定命名服务
NamingContext ncRef = NamingContextHelper.narrow(orb.resolve_initial_references("NameService"));
NameComponent nc = new NameComponent("Hello", "");
NameComponent path[] = {nc};
ncRef.rebind(path, obj);
//**POA管理器
manager.activate();
//等待处理客户程序的请求
System.out.println("HelloWorld is running! 软工1704班 张佳欣 ");
orb.run();
}catch (Exception e) {
System.err.println("ERROR: " + e);
e.printStackTrace(System.out);
}
}
}
4 编写并编译客户端程序: HelloWorldClient.java
import sample.*;
import org.omg.CosNaming.*;
import org.omg.CORBA.*;
public class HelloWorldClient {
public static void main(String args[]) {
try{
ORB orb = ORB.init(args, null);
org.omg.CORBA.Object objRef = orb.resolve_initial_references("NameService");
NamingContext ncRef = NamingContextHelper.narrow(objRef);
NameComponent nc = new NameComponent("Hello","");
NameComponent path[] = {nc};
HelloWorld helloWorld = HelloWorldHelper.narrow(ncRef.resolve(path));
String hello = helloWorld.sayHello();
System.out.println(hello);
} catch (Exception e) {
System.out.println("ERROR : " + e) ;
e.printStackTrace(System.out);
}
}
}
题目2.JAVA版CORBA程序2——Counter
2.组件实现
1 编写IDL接口counter.idl：
module CounterApp{
interface Counter{
readonly attribute long value;
void inc();
void dec();
};
};
2编译IDL接口：E:\work >idlj –fall counter.idl
编译结果生成CounterApp包，生成下述文件
_CounterStub.java
Counter.java
CounterHelper.java
CounterHolder.java
CounterOperations.java
CounterPOA.java
3 编写并编译对象实现代码：CounterImpl.java
import CounterApp.*;
public class CounterImpl extends CounterPOA {
private int count;
public CounterImpl(){
count = 0;
}
public void inc(){
count++;
}
public void dec(){
count - -;
}
public int value(){
return count;
}
}
4 编写并编译服务端程序: Server.java
import CounterApp.*;
import java.io.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import org.omg.CORBA.portable.*;
import org.omg.PortableServer.*;
public class Server {
public static void main(String[] args){
try{
ORB orb = ORB.init(args, null);
org.omg.CORBA.Object poaobj = orb.resolve_initial_references ("RootPOA");
org.omg.PortableServer.POA rootPOA = org.omg.PortableServer.POAHelper.narrow(poaobj);
org.omg.PortableServer.POAManager manager = rootPOA.the_POAManager();
CounterImpl c_impl = new CounterImpl();
Counter c = c_impl._this(orb);
NamingContext ncRef = NamingContextHelper.narrow(orb.resolve_initial_references("NameService"));
NameComponent nc = new NameComponent("Count", "");
NameComponent path[] = {nc};
ncRef.rebind(path, c);
FileOutputStream file = new FileOutputStream("Counter.ref");
PrintWriter writer = new PrintWriter(file);
String ref = orb.object_to_string(c);
writer.println(ref);
writer.flush();
file.close();
System.out.println("Server started."+" Stop:Ctrl-c");
rootPOA.the_POAManager().activate();
orb.run();
}catch(IOException ex){
System.out.println("File error:"+ex.getMessage());
System.exit(2);
}catch(Exception ex){
System.out.println("Exception: "+ex.getMessage());
System.exit(1);
}
}
}
5 编写并编译客户端程序: Client.java
import CounterApp.*;
import java.util.*;
import java.io.*;
import org.omg.CORBA.*;
import org.omg.CosNaming.*;
public class Client {
public static void main(String[] args){
try{
ORB orb = ORB.init(args, null);
org.omg.CORBA.Object obj = orb.resolve_initial_references("NameService");
NamingContext ncRef = NamingContextHelper.narrow(obj);
NameComponent nc = new NameComponent("Count","");
NameComponent path[] = {nc};
String ref = null;
try{
Scanner reader = new Scanner(new File("Counter.ref"));
ref = reader.nextLine();
}catch(IOException ex){
System.out.println("File error: "+ex.getMessage());
System.exit(2);
}
obj = orb.string_to_object(ref);
if(obj == null){
System.out.println("Invalid IOR");
System.exit(4);
}
Counter c = null;
try{
c = CounterHelper.narrow(obj);
}catch(BAD_PARAM ex){
System.out.println("Narrowing failed");
System.exit(3);
}
int inp = -1;
do{
System.out.print("Counter value: "+c.value()+"\nAction(+/-/e)?");
System.out.flush();
do{
try{
inp = System.in.read();
}catch(IOException ioe){}
}while(inp != '+' && inp != '-' && inp != 'e');
if(inp == '+')
c.inc();
else if(inp == '-')
c.dec();
}while(inp != 'e');
}catch(Exception ex){
System.out.println("Exception: "+ex.getMessage());
System.exit(1);
}
}
}
二．CORBA模型分析
三．运行结果
1.编译IDL接口：E:\work >idlj –fall counter.idl
编译结果生成sample包，生成下述文件
（1）启动名字服务器：E:\work >tnameserv -ORBInitialPort 1050
（2）启动服务端程序：E:\work >java HelloWorldServer -ORBInitialPort 1050
输出：编写实现显示“Hello，World！软工1704班 张佳欣”字符串。
（3）启动客户端程序：E:\work >java HelloWorldClient -ORBInitialPort 1050
输出：Hello World! 软工1704班 张佳欣
2编译IDL接口：E:\work >idlj –fall counter.idl
编译结果生成CounterApp包，生成下述文件
（1）启动名字服务器：E:\work >tnameserv -ORBInitialPort 1050
（2）启动服务端程序：E:\work >java Server -ORBInitialPort 1050
输出：Server started. Stop: Ctrl-c
（3）启动客户端程序：E:\work >java Client -ORBInitialPort 1050
四．经验归纳：
通过这次的试验，初步了解了COBAR组件模型，虽然还是不那么清楚。首先创建IDL接口，编译idlj生成包。然后编写并编译服务端，客户端，然后启动程序。刚开始自己不是很了解，在创建好.Java文件后没有编译直接运行发现出错。后来做好第一个，第二个也就好，实现输出了简单的HelloWorld班级姓名以及实现加减乘除。