client.java

java的客户端程序

import org.omg.CORBA.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import java.io.*;
import ssd8exercise5creator.*;
import ssd8exercise5.*;

/**
 * class <em>Client</em> represents a distributed to do list system 
 * client implemented in Corba.
 *
 * @author iCarnegie, inc (VP)
 * @version 1.0
 */
public class Client {

    public static void main( String [] args ) {

	int choice = 0, meetingid = 0;
	String username, password, recipientname, message, start_time, end_time, otheruser, description,
	    queryReturn;

	/*
	 * Setup to read from the keyboard.
	 */
	BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));

	/*
	 * Create an instance of the message center interface.
	 */
	TodolistInterface toDoList;
	TodolistCreatorInterface toDoListCreator;
	try {

	    /*
	     * Create and initialize the orb.	     
	     */
	    ORB orb = ORB.init( args, null );

	    /*
	     * Get the root naming context.
	     */
	    org.omg.CORBA.Object objectReference = orb.resolve_initial_references( "NameService" );
	    NamingContext namingContextReference = NamingContextHelper.narrow( objectReference );

	    /*
	     * Find the object named TodolistCreator.
	     */
	    NameComponent nc = new NameComponent("TodolistCreator","");
      	    NameComponent path[] = { nc };	       
	    toDoListCreator = TodolistCreatorInterfaceHelper.narrow(namingContextReference.resolve(path));
	    /*
	     * Loop forever while displaying the menu and performing
	     * operations for the user.
	     */
	    while ( true ) {
		
		System.out.println( "********** Distributed To Do List ************ " );
		System.out.println( "(1) Register a new user" );
		System.out.println( "(2) Clear a user's to do list" );
		System.out.println( "(3) Delete a to do list item" );
		System.out.println( "(4) Add an item to the to do list" );
		System.out.println( "(5) Query items from the to do list" );
		System.out.println( "(6) Exit" );
		System.out.println( "**********************************************" );
		System.out.println( "Enter choice: " );
		choice = Integer.parseInt( keyboard.readLine() );
		
		/*
		 * Register a member.  Print an error message if the 
		 * registration fails or a success message
		 * if the registration succeeds.
		 */
		if (choice==1) {
		    System.out.println( "Enter username: " );
		    username = keyboard.readLine();
		    System.out.println( "Enter password: " );
		    password = keyboard.readLine();
		    if (!toDoListCreator.register(username,password)) {
			System.out.println( "Trouble registering!" );
		    } else {
			System.out.println( "Registration Successful!" );
		    }
		}
		
		/*
		 * Clear a to do list.  Get the username and password.  Print a 
		 * success message if the clear succeeds or a failure message
		 * if the clear fails.
		 */
		if (choice==2) {
		    System.out.println( "Enter username: " );
		    username = keyboard.readLine();
		    System.out.println( "Enter password: " );
		    password = keyboard.readLine();
		    nc = new NameComponent(username,"");
		    NameComponent path2[] = { nc };
		    toDoList = TodolistInterfaceHelper.narrow(namingContextReference.resolve(path2));
		    if ( toDoList.clear( username, password ) ) {
			System.out.println( " To Do List for " + username + " has been successfully cleared." );
		    } else {
			System.out.println( "Trouble clearing to do list for " + username + "!" );
			System.out.println( "Try a different username/password!" );
		    }
		}
		
		/*
		 * Attempt to delete a meeting.  The user must enter
		 * the username, password, and meeting id.  Print a 
		 * success message if the delete succeeds and a failure 
		 * notice if the deletion fails.
		 */
		if ( choice==3 ) {
		    System.out.println( "Enter username: " );
		    username = keyboard.readLine();
		    System.out.println( "Enter password: " );
		    password = keyboard.readLine();
		    System.out.println( "Enter id of to do list item to delete: " );
		    meetingid = Integer.parseInt( keyboard.readLine() );
		    nc = new NameComponent(username,"");
		    NameComponent path2[] = { nc };
		    toDoList = TodolistInterfaceHelper.narrow(namingContextReference.resolve(path2));
		    if ( toDoList.delete(username, password, meetingid ) ) {
			System.out.println( "List item successfully deleted!" );
		    } else {
			System.out.println( "Could not delete list item!" );
			System.out.println( "Try a different username/password/list item id!" );
		    }
		}

		/*
		 * Add an item to the to-do list.  Print a success 
		 * message if the addition succeeds.  The user must enter his username, password,
		 * start time, end time, and item description.
		 */
		if (choice==4) {
		    System.out.println( "Enter username: " );
		    username = keyboard.readLine();
		    System.out.println( "Enter password: " );
		    password = keyboard.readLine();
		    System.out.println( "Enter the start time" );
		    System.out.println( "For example, 12/22/2003-12:45" );
		    start_time = keyboard.readLine();
		    System.out.println( "Enter the end time" );
		    System.out.println( "For example, 12/22/2003-12:45" );
		    end_time = keyboard.readLine();
		    System.out.println( "Enter the to do list item description" );
		    description = keyboard.readLine();
		    nc = new NameComponent(username,"");
		    NameComponent path2[] = { nc };
		    toDoList = TodolistInterfaceHelper.narrow(namingContextReference.resolve(path2));
		    if ( toDoList.add( username, password, start_time, end_time, description ) ) {
			System.out.println( "To do list item added successfully!" );
			} else {
			    System.out.println( "Failed to add list item!" );
			}
		}
		
		/*
		 * Query a meeting.  User must enter username, password, start time, 
		 * and end time.  Print an error message if there were no meetings matching
		 * the criteria.  Otherwise print the meetings matching the criteria.
		 */
		if (choice==5) {
		    System.out.println( "Enter username: " );
		    username = keyboard.readLine();
		    System.out.println( "Enter password: " );
		    password = keyboard.readLine();
		    System.out.println( "Enter the start time" );
		    System.out.println( "For example, 12/22/2003-12:45" );
		    start_time = keyboard.readLine();
		    System.out.println( "Enter the end time" );
		    System.out.println( "For example, 12/22/2003-12:45" );
		    end_time = keyboard.readLine();
		    nc = new NameComponent(username,"");
		    NameComponent path2[] = { nc };
		    toDoList = TodolistInterfaceHelper.narrow(namingContextReference.resolve(path2));
		    queryReturn = toDoList.query( username, password, start_time, end_time );
		    if (queryReturn==null || queryReturn.length()==0) {
			System.out.println( "No to do list items matched criteria!" );
		    } else {
			System.out.println( "To do list items matching criteria: " );
			System.out.println( queryReturn );
		    }
		}

		/*
		 * Exit.
		 */
		if (choice==6) {
		    System.exit(0);
		}
	    }
	} catch( Exception e ) {
	    e.printStackTrace();
	}
    }
}