来自另一个类的Java调用方法

Question

Disclaimer - this is for an assignment, I'm trying to figure out why my code is giving me an error.

Background:

So the assignment is basically to make edits to SimpleChat, a client-server framework for which the teacher has given us the code. I am trying to implement a chat console from the server side, and implement actions that begin with hashtags. So I have a "handleMessageFromServer" method in my server file (called "EchoServer"), and am trying to call it from the server console (aptly named "Server Console"). I'll put the relevant code below, and explain it:

I'll edit what I've put, I'll put the whole files with comments.

Below is the "EchoServer" file. The more important bits relevant to my question are the "handleMessageFromServer" method, which I am trying to call from the other file and pass in information, as well as the EchoServer constructor, which I am using in the other file to create an instance.

import java.io.*;
import ocsf.server.*;
import common.*;

/**
 * This class overrides some of the methods in the abstract 
 * superclass in order to give more functionality to the server.
 *
 * @author Dr Timothy C. Lethbridge
 * @author Dr Robert Laganière
 * @author François Bélanger
 * @author Paul Holden
 * @version July 2000
 */
public class EchoServer extends AbstractServer 
{
  //Class variables *************************************************

  /**
   * The default port to listen on.
   */
  final public static int DEFAULT_PORT = 5555;

  //Constructors ****************************************************

  /*
   * An interface type variable, will allow the implementation of the 
   * Display method in the client.
   * 
   */
  public ChatIF server;
  /**
   * Constructs an instance of the echo server.
   *
   * @param port The port number to connect on.
   */
  public EchoServer(int port, ChatIF server)
  {
      super(port);
      this.server = server;
  }

  //Instance methods ************************************************

  /**
   * This method handles any messages received from the client.
   *
   * @param msg The message received from the client.
   * @param client The connection from which the message originated.
   */
  public void handleMessageFromClient
    (Object msg, ConnectionToClient client)
  {
    System.out.println("Message received: " + msg + " from " + client);
    this.sendToAllClients(msg);
  }

  /**
   * This method handles any messages received from the server console.
   *
   * @param msg The message received from the server.
   * @param server The connection from which the message originated.
   */
  public void handleMessageFromServer(String message)
  {
    if (message.charAt(0) == '#')
    {
      serverCommand(message);
    }
    else
    {
      server.display(message);
      this.sendToAllClients("SERVER MSG> " + message);
    }
  }
  /*This method allows us to run commands from the server console
   * 
   */
  public void serverCommand(String command)
  {
      if (command.equalsIgnoreCase("quit")) System.exit(0);      /////Shuts the system down
      else if (command.equalsIgnoreCase("#stop")) stopListening();  ///Stops listening for connections
      else if (command.equalsIgnoreCase("#close"))            ///////closes all connections
      {
          try close();
                  catch(IOException ex) {
                      server.display("Could not close connection");
                  }
      }
      else if (command.toLowerCase().startsWith("#setport"))           /////Sets port when not listening
      {
        if (!isListening() && getNumberOfClients() == 0)
        {
            //////If there are no connected clients, and
            //////we're not listening for new ones, we can 
            ////assume that the server is closed (close() has been 
            ////called. 
            String portNum = command.substring(s.indexOf("<") + 1)
            portNum = portnum.substring(0, s.indexOf(">"));
            int num = Integer.parseInt(portNum);
            setPort(num);
            server.display("The server port has been changed to port" + getPort());
        }
        else
        {
            server.display("Port cannot be changed");
        }
        else if (command.equalsIgnoreCase("#start"))     ///////starts listening for clients if not already
        {
            if (!isListening())
            {
                try listen();
                catch (Exception ex)
                {
                    server.display("Could not listen for clients!");
                }
            }
            else
            {
                server.display("Already listening for clients");
            }
        }
        else if (message.equalsIgnoreCase("#getport"))    //////gets the port number
        {
            server.display("Current port: " + Integer.toString(getPort()));
        }
      }
  }

  /**
   * This method overrides the one in the superclass.  Called
   * when the server starts listening for connections.
   */
  protected void serverStarted()
  {
    System.out.println
      ("Server listening for connections on port " + getPort());
  }

  /**
   * This method overrides the one in the superclass.  Called
   * when the server stops listening for connections.
   */
  protected void serverStopped()
  {
    System.out.println
      ("Server has stopped listening for connections.");
  }

  //Class methods ***************************************************

  /**
   * This method is responsible for the creation of 
   * the server instance (there is no UI in this phase).
   *
   * @param args[0] The port number to listen on.  Defaults to 5555 
   *          if no argument is entered.
   */
  public static void main(String[] args) 
  {
    int port = 0; //Port to listen on

    try
    {
      port = Integer.parseInt(args[0]); //Get port from command line
    }
    catch(Throwable t)
    {
      port = DEFAULT_PORT; //Set port to 5555
    }

    EchoServer sv = new EchoServer(port);

    try 
    {
      sv.listen(); //Start listening for connections
    } 
    catch (Exception ex) 
    {
      System.out.println("ERROR - Could not listen for clients!");
    }
  }
}
//End of EchoServer class

Below is the ServerConsole file, where I am creating an instance of the EchoServer class so that I may pass in information. The purpose of this file is to create an environment where the server side can send text for the SimpleChat application. The text then gets passed back to the EchoServer class, where it can be used for commands (all the commands begin with hashtags). I am currently getting an error in the "accept" method, when trying to call echoServer.handleMessageFromServer(message). The error is "The method handleMessageFromServer(String) is undefined for the type EchoServer".

import java.io.*;
import client.*;
import common.*;

/**
 * This class constructs the UI for a chat client.  It implements the
 * chat interface in order to activate the display() method.
 * Warning: Some of the code here is cloned in ServerConsole 
 *
 * @author François Bélanger
 * @author Dr Timothy C. Lethbridge  
 * @author Dr Robert Laganière
 * @version July 2000
 */
public class ServerConsole implements ChatIF 
{
  //Class variables *************************************************

  /**
   * The default port to connect on.
   */
  final public static int DEFAULT_PORT = 5555;

  //Instance variables **********************************************

  /**
   * The instance of the server that created this ConsoleChat.
   */
  //Constructors ****************************************************
  EchoServer echoServer;
  /**
   * Constructs an instance of the ClientConsole UI.
   *
   * @param host The host to connect to.
   * @param port The port to connect on.
   */
  public ServerConsole(int port) 
  {
   this.echoServer = new EchoServer(port);
  } 

  //Instance methods ************************************************

  /**
   * This method waits for input from the console.  Once it is 
   * received, it sends it to the client's message handler.
   */
  public void accept() 
  {
    try
    {
      BufferedReader fromConsole = 
        new BufferedReader(new InputStreamReader(System.in));
      String message;

      while (true) 
      {
        message = fromConsole.readLine();
        ///////////////ADDED FOR E50B       MA/ND
        echoServer.handleMessageFromServer(message);
        ///////////////ADDED FOR E50B       MA/ND
      }
    } 
    catch (Exception ex) 
    {
      System.out.println
        ("Unexpected error while reading from console!");
    }
  }

  /**
   * This method overrides the method in the ChatIF interface.  It
   * displays a message onto the screen.
   *
   * @param message The string to be displayed.
   */
  public void display(String message) 
  {
                 System.out.println(message);
  }


  //Class methods ***************************************************

  /**
   * This method is responsible for the creation of the Client UI.
   *
   * @param args[0] The host to connect to.
   */
  public static void main(String[] args) 
  {
    int port = 0;  //The port number

    try
    {
      String host = args[0];
    }
    catch(ArrayIndexOutOfBoundsException e)
    {
     String host = "localhost";
    }
    ServerConsole chat= new ServerConsole(DEFAULT_PORT);
    chat.accept();  //Wait for console data
  }
}
//End of ConsoleChat class

I think I might not be constructing the instance right, but any help is greatly appreciated guys!

Answer 1

Your echoserver class has the following contructor:

public EchoServer(int port, ChatIF server)
  {
      super(port);
      this.server = server;
  }

note it takes in two parameters.

your call to the EchoServer is however only injecting a port

this.echoServer = new EchoServer(port);

Without seeing all your code my guess would be that Echoserver extends some other Server class that does not have the method you want.