chatserveradministrator.java

高级java2 大学教程(含源码,经典的Java学习教程

// ChatServerAdministrator.java
// ChatServerAdministrator is a utility program for launching
// and terminating the Activatable ChatServer.
package com.deitel.messenger.rmi.server;

// Java core packages
import java.rmi.*;
import java.rmi.activation.*;
import java.util.*;

public class ChatServerAdministrator {
   
   // set up activatable server object
   private static void startServer( String policy, 
      String codebase ) throws Exception
   {
      // set up RMI security manager
      System.setSecurityManager( new RMISecurityManager() );

      // set security policy for ActivatableGroup JVM
      Properties properties = new Properties(); 
      properties.put( "java.security.policy", policy );

      // create ActivationGroupDesc for activatable object
      ActivationGroupDesc groupDesc = 
         new ActivationGroupDesc( properties, null );

      // register activation group with RMI activation system 
      ActivationGroupID groupID = 
         ActivationGroup.getSystem().registerGroup( groupDesc );

      // create activation group
      ActivationGroup.createGroup( groupID, groupDesc , 0 );

      // activation description for ChatServerImpl
      ActivationDesc description = new ActivationDesc( 
         "com.deitel.messenger.rmi.server.ChatServerImpl", 
         codebase, null );

      // register description with rmid
      ChatServer server = 
         ( ChatServer ) Activatable.register( description ); 
      System.out.println( "Obtained ChatServerImpl stub" );

      // bind ChatServer in registry
      Naming.rebind( "ChatServer", server ); 
      System.out.println( "Bound object to registry" ); 
      
      // terminate setup program
      System.exit( 0 );
      
   } // end method startServer
   
   // terminate server
   private static void terminateServer( String hostname ) 
      throws Exception
   {
      // lookup ChatServer in RMI registry
      System.out.println( "Locating server ..." );
      StoppableChatServer server = ( StoppableChatServer ) 
         Naming.lookup( "rmi://" + hostname + "/ChatServer" );

      // terminate server
      System.out.println( "Stopping server ..." );
      server.stopServer();
         
      // remove ChatServer from RMI registry
      System.out.println( "Server stopped" );      
      Naming.unbind( "rmi://" + hostname + "/ChatServer" );
      
   } // end method terminateServer
   
   // launch ChatServerAdministrator application
   public static void main( String args[] ) throws Exception
   {
      // check for stop server argument
      if ( args.length == 2 ) {
         
         if ( args[ 0 ].equals( "stop" ) )
            terminateServer( args[ 1 ] );
      
         else printUsageInstructions();
      }
      
      // check for start server argument
      else if ( args.length == 3 ) {
         
         // start server with user-provided policy, codebase
         // and Registry hostname
         if ( args[ 0 ].equals( "start" ) )
            startServer( args[ 1 ], args[ 2 ] );
         
         else printUsageInstructions();
      }
      
      // wrong number of arguments provided, so print instructions
      else printUsageInstructions();
      
   } // end method main
   
   // print instructions for running ChatServerAdministrator
   private static void printUsageInstructions()
   {
      System.err.println( "\nUsage:\n" +
         "\tjava com.deitel.messenger.rmi.server." +
         "ChatServerAdministrator start <policy> <codebase>\n" +
         "\tjava com.deitel.messenger.rmi.server." +
         "ChatServerAdministrator stop <registry hostname>" );
   }
}

/**************************************************************************
 * (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 *************************************************************************/