Java实现CORBA静态绑定（七）

本文主要内容涉及：

• CORBA基本架构
• IDL文件编写
• POA示例实现
• POA+TIE示例实现
• ImplBase示例实现
• ImplBase+TIE示例实现
• Persistent示例实现

HiPersistent.idl

module HiCorba
{
	interface HiPersistent
	{
		string sayHiTo(in string someone);
		long add(in long numa, in long numb);
		oneway void shutdown();
	};
};

JDK提供了工具，可以直接生成stubs及skeletons接口代码：

idlj -fall HiPersistent.idl

编写server端代码：

import java.util.Properties;
import org.omg.CORBA.Object;
import org.omg.CORBA.ORB;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContextExt;
import org.omg.CosNaming.NamingContextExtHelper;
import org.omg.CORBA.Policy;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.*;
import org.omg.PortableServer.Servant;
import HiCorba.*;

class HiPersistentImpl extends HiPersistentPOA {
	private ORB orb;
	public void setORB(ORB orb_val) {
		orb = orb_val;
	}
	// implement sayHiTo() method
	public String sayHiTo(String someone) {
		return "\nHi, "+someone+" !"+"\n";
	}
	// implement add() method
	public int add(int numa, int numb) {
		return numa+numb;
	}
	// implement shutdown() method
	public void shutdown() {
		orb.shutdown(false);
	}
}

public class HiPersistentServer {
	public static void main( String args[] ) {
		try {
			// Step 1: Instantiate the ORB
			ORB orb = ORB.init(args, null);

			// Step 2: Instantiate the servant
			HiPersistentImpl impl = new HiPersistentImpl();
		        impl.setORB(orb);

			// Step 3 : Create a POA with Persistent Policy
			// Step 3-1: Get the rootPOA 
			POA rootPOA = POAHelper.narrow(orb.resolve_initial_references("RootPOA"));
			// Step 3-2: Create the Persistent Policy
			Policy[] persistentPolicy = new Policy[1];
			persistentPolicy[0] = rootPOA.create_lifespan_policy(LifespanPolicyValue.PERSISTENT);
			// Step 3-3: Create a POA by passing the Persistent Policy
			POA persistentPOA = rootPOA.create_POA("childPOA", null, persistentPolicy ); 
			// Step 3-4: Activate HiPersistentPOA's POAManager, Without this
			// All calls to HiPersistent Server will hang because POAManager
			// will be in the 'HOLD' state.
			persistentPOA.the_POAManager().activate( );
			
			// Step 4: Associate the servant with HiPersistentPOA
			persistentPOA.activate_object( impl );

			// Step 5: Resolve RootNaming context and bind a name for the
			// servant.
			// NOTE: If the Server is persistent in nature then using Persistent
			// Name Service is a good choice. Even if ORBD is restarted the Name
			// Bindings will be intact. To use Persistent Name Service use
			// 'NameService' as the key for resolve_initial_references() when
			// ORBD is running.
			org.omg.CORBA.Object obj = orb.resolve_initial_references( "NameService" );
			NamingContextExt rootContext = NamingContextExtHelper.narrow( obj );

			NameComponent[] nc = rootContext.to_name( "HiPersistent" );
			rootContext.rebind( nc, persistentPOA.servant_to_reference( impl ) );

			// Step 6: We are ready to receive client requests
			orb.run();
		} catch ( Exception e ) {
			System.err.println( "Exception in Persistent Server Startup " + e );
		}
	}
}

编写client端代码：

import java.util.Properties;
import org.omg.CORBA.ORB;
import org.omg.CORBA.OBJ_ADAPTER;
import org.omg.CosNaming.NamingContext;
import org.omg.CosNaming.NamingContextHelper;
import org.omg.CosNaming.NameComponent;
import org.omg.PortableServer.POA;
import HiCorba.*;

public class HiPersistentClient {
	public static void main(String args[]) {
		try {
			// Step 1: Instantiate the ORB
			ORB orb = ORB.init(args, null);

			// Step 2: Resolve the PersistentHelloServant by using INS's
			// corbaname url. The URL locates the NameService running on
			// localhost and listening on 1900 and resolve 
			// 'PersistentServerTutorial' from that NameService
			org.omg.CORBA.Object obj = orb.string_to_object("corbaname::localhost:1900#HiPersistent");
			HiPersistent hiPersistent = HiPersistentHelper.narrow( obj );

			// Step 3: Call the sayHello() method every 60 seconds and shutdown
			// the server. Next call from the client will restart the server,
			// because it is persistent in nature.
			while( true ) {
				System.out.println( "Calling HiPersisten Server.." );
				System.out.println("Message From HiPersisten Server: " + hiPersistent.sayHiTo("neohope") );
				System.out.println("70 + 80 = " + hiPersistent.add(70, 80) );
				System.out.println( "Shutting down HiPersistent Server.." );
				hiPersistent.shutdown( );
				Thread.sleep(2000);
			}
		} catch ( Exception e ) {
			System.err.println( "Exception in HiPersistentClient.java..." + e );
			e.printStackTrace( );
		}
	}
}

编译代码：

javac *.java HiCorba/*.java

测试，在三个shell或cmd窗口中依次运行：

#shell01
orbd -ORBInitialPort 1900 -serverPollingTime 200

#shell02
servertool -ORBInitialPort 1900
>>欢迎使用 Java IDL 服务器工具
>>请在提示处输入命令
> register -server HiPersistentServer -applicationName s1 -classpath .

#shell03
java HiPersistentClient
>>Calling HiPersisten Server..
>>Message From HiPersisten Server:
>>Hi, neohope !
>>70 + 80 = 150
>>Shutting down HiPersistent Server..
>>
>>Calling HiPersisten Server..
>>Message From HiPersisten Server:
>>Hi, neohope !
>>70 + 80 = 150
>>Shutting down HiPersistent Server..