server.java

Java 3D Desktop Environment旨在使用Java 3D来创建一个3D桌面环境。功能包括：分布式的应用程序

/*
 * Copyright (c) 2000, Niklas Mehner 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 * 
 *   - Redistributions of source code must retain the above copyright 
 *     notice, this list of conditions and the following disclaimer.
 * 
 *   - Redistributions in binary form must reproduce the above copyright 
 *     notice, this list of conditions and the following disclaimer in 
 *     the documentation and/or other materials provided with the 
 *     distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */ 
package org.j3de;
   
import java.io.FileOutputStream;
import java.io.File;
import java.io.IOException;                            
import java.rmi.Naming;
import java.rmi.RMISecurityManager;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.server.RemoteServer;
import java.rmi.registry.LocateRegistry;
import java.lang.reflect.InvocationTargetException;

import javax.xml.parsers.ParserConfigurationException;

import org.xml.sax.SAXException;

import org.j3de.exception.LogExceptionHandler;
import org.j3de.exception.ExceptionHandler;     
import org.j3de.interfaces.ApplicationServer;
import org.j3de.interfaces.EnvironmentServer;
import org.j3de.server.ClassPathManager;
import org.j3de.server.EnvironmentList;
import org.j3de.server.ApplicationList;
import org.j3de.server.DefaultApplicationServer;
import org.j3de.server.DefaultEnvironmentServer;
import org.j3de.util.Configuration;
import org.j3de.util.ConfigurationException;
        
/**
 * Server is the main class of the j3de server. It is responsible for parsing the configuration file
 * and creating all necessairy components, as well as setting up exception-handling and logging.
 *
 * The server consists basically of a list of environments and a list of applications, that are provided
 * to the clients. Additional a webserver to server the needed (jar-)files can be started (not yet implemented). 
 *
 * @author Niklas Mehner
 * @version $Revision: 1.7 $, $Date: 2000/09/08 20:50:56 $
 * @since  j3de 1.0
 */
public class Server {      
  private static final String CONFIG_FILE  = "config-server.xml";
  private static final String LOG_FILE     = "log" + File.separator + "server.log";
  private static final String TRUE         = "true";
  private static final String APPLICATIONS = "applications";
  private static final String ENVIRONMENTS = "environments";
  
  private static final String CREATE_REGISTRY         = "createRegistry";   
  private static final String CREATE_REGISTRY_DEFAULT = "false";
  
  private static final String REGISTRY_PORT           = "registryPort";   
  private static final String REGISTRY_PORT_DEFAULT   = "1099";

  private static final String APP_BINDING_NAME            = "appBindingName";   
  private static final String APP_BINDING_NAME_DEFAULT    = "j3de-appserver";

  private static final String ENV_BINDING_NAME            = "envBindingName";   
  private static final String ENV_BINDING_NAME_DEFAULT    = "j3de-envserver";

  private static final String RMI_CLASS_PATH              = "rmi_classpath";   
  private static final String RMI_CLASS_PATH_DEFAULT      = "";
  
  
  private Configuration configuration;
  private String configFileName;
  private ApplicationList applicationList;
  private EnvironmentList environmentList;
  private ApplicationServer applicationServer;        
  private EnvironmentServer environmentServer;        
  private ClassPathManager  classPathManager;
  
  private boolean createRegistry;
  private int     registryPort;
  private String  appBindingName;
  private String  envBindingName;
  private String  rmiClassPath;
 
  /** Creates a new Server. All informations are read from the configuration file.
    * @param configFileName path to the configuration file.
    * @throws IOException if the configuration file cannot be opened.
    * @throws ParserConfigurationException if the xml parser is not configured correctly.
    * @throws SAXException if the configuration file cannot be parsed.
    * @throws ConfigurationException if there are semantic errors in the configuration file.
    */
  public Server(String configFileName) throws IOException,
                                              ParserConfigurationException, 
                                              SAXException,
                                              ConfigurationException {
    
    System.setProperty("java.rmi.server.useCodebaseOnly", "true");
    if (System.getSecurityManager() == null) {
      System.setSecurityManager(new RMISecurityManager());
    }   
    
    this.configFileName = configFileName;
    
    configuration = new Configuration(configFileName); 
    
    createRegistry  = configuration.getProperty(CREATE_REGISTRY, 
                                                CREATE_REGISTRY_DEFAULT,           
                                                ExceptionHandler.SHOW_WARNING)
                                               .toLowerCase().equals(TRUE);
    
    appBindingName     = configuration.getProperty(APP_BINDING_NAME, 
                                                   APP_BINDING_NAME_DEFAULT, 
                                                   ExceptionHandler.SHOW_WARNING); 
 
    envBindingName     = configuration.getProperty(ENV_BINDING_NAME, 
                                                   ENV_BINDING_NAME_DEFAULT, 
                                                   ExceptionHandler.SHOW_WARNING); 
    
    registryPort    = new Integer(configuration.getProperty(REGISTRY_PORT, 
                                                            REGISTRY_PORT_DEFAULT, 
                                                            ExceptionHandler.SHOW_WARNING)).intValue(); 
    rmiClassPath    = configuration.getProperty(RMI_CLASS_PATH, 
                                                RMI_CLASS_PATH_DEFAULT, 
                                                ExceptionHandler.SHOW_WARNING); 
    
    applicationList = (ApplicationList)configuration.getComponent(APPLICATIONS, 
                       org.j3de.server.DefaultApplicationList.class);     
 
    environmentList = (EnvironmentList)configuration.getComponent(ENVIRONMENTS, 
                       org.j3de.server.DefaultEnvironmentList.class); 
     
     classPathManager = new ClassPathManager(environmentList, applicationList, rmiClassPath); 
    classPathManager.setServerClassPath();
    
    applicationServer = new DefaultApplicationServer(applicationList);
    environmentServer = new DefaultEnvironmentServer(environmentList);
    
    if (createRegistry)
      LocateRegistry.createRegistry(registryPort);
    
    RemoteServer.setLog(new FileOutputStream("log" + File.separator + "rmi.log"));
    
    UnicastRemoteObject.exportObject(applicationServer);
    UnicastRemoteObject.exportObject(environmentServer);
       
    Naming.rebind(appBindingName, applicationServer);       
    Naming.rebind(envBindingName, environmentServer);
    System.out.println("Server ready");
  }  
 
  /** Saves the configuration of the given server.
    * @param server the server the configuration should be saved for.
    * @param fileName the fileName the configuration should be saved to.
    */ 
  public static void saveConfiguration(Server server, String fileName) {    
    try {
      if ((server != null) && server.configuration.isConfigurationChanged())      
        server.configuration.saveConfiguration(fileName);         
    } catch (IOException e) {
      ExceptionHandler.handleFatalException(e);
    }
  }

  /** 
   * Starts the server. 
   * @param args Contains either a configuration file or is empty. In that case the server
   *   tries to read the default configuration file <code>config-server.xml</code>
   */
  public static void main(String[] args) {    
    try {                           
      Server server = null;
      String configFileName = CONFIG_FILE;
    
      try {                                       
        if (args.length == 1) 
          configFileName = args[0];    
         
        new LogExceptionHandler(LOG_FILE);
     
        server = new Server(configFileName);
      
      } catch (Exception e) {       
        e.printStackTrace();
        ExceptionHandler.handleFatalException(e);
      } finally { 
        saveConfiguration(server, configFileName);            
      }
    } catch (Exception e) {
      e.printStackTrace();
    } 
  }
}