continuously testing for the existence of the client program?


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Thread: continuously testing for the existence of the client program?

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  1. #1
    Lim Wing Hoe Guest

    continuously testing for the existence of the client program?

    OK,
    I'm going to have a server that keeps track of online users.

    When a client program logs onto the server [LOGON, username, ipaddress], the
    client's data [username, ip address] will be added to the list of online
    users.

    At the same time, the entire list of online users will be sent out to the
    current client's online user JInternalFrame.

    If the user quits the client program, upon detecting the windowClosing
    method, inside the stop() method, I will write a data stream [LOGOUT,
    username, ipaddress] back to the server to have this username removed from
    the server.

    These two steps are OK for me to write. However, let's say, if the client
    hangs or ran into some exceptions, the server will need a way to test if the
    user is still online. So, if the client program do not respond to the
    request from the server, the server itself will remove the user from the
    online users list and re-broadcast the current online users list to all
    other connected clients.

    How should I go about doing this? Checking for the existence of the client
    program to see whether it's still 'alive' or not.

    And, can I keep the online users that contains two fields [username,
    ipaddress] in a Vector()?

    How do I write them and how do I retrieve them?

    Thanks.



    --



    Best Regards,
    Wing Hoe
    ---------------------------------------------------------------
    ICQ: 2213281
    Email: winghoe@hotmail.com
    www: http://pwp.maxis.net.my/winghoe
    ---------------------------------------------------------------







  2. #2
    Mala Guest

    RE: continuously testing for the existence of the client program?

    Hello Winghoe

    You can easily keep the online users that contains two fields [username, ipaddress] in a Vector.

    Refer code -

    import java.net.InerAddress;
    public class User {
    private String username;
    private InetAddress IPAddress;

    public User(String name, InetAddress ipAddress) {
    username = name;
    IPAddress = ipAddress;
    }

    public String getUsername {return username;}
    public InetAddress getIPAddress (return IPAddress:}
    public void setUsername (String name) {username = name
    public void setIPAddress(InetAddress addr) {
    IPAddress = addr;
    }
    }

    import java.util.*;
    public class Test {
    public static void main(String args[]) {
    Vector vector = new Vector();
    InetAddress addr = null;

    try {addr = InetAddress.getLocalHost();}
    catch(Exception e) {}

    User user1 = new User("Winghoe", addr);
    vector.addElement(user1);

    //retreive values from vecor
    for (int 1=0; i<vecor.size; i++) {
    User u1 = (User)vector.elementAt(i);
    System.out.println(u1.getUsername());
    System.out.println(u1.getIPAddress());

    }
    }
    }


    If you find the above solution useful, let me know.




    >OK,
    >I'm going to have a server that keeps track of online users.
    >
    >When a client program logs onto the server [LOGON, username, ipaddress], the
    >client's data [username, ip address] will be added to the list of online
    >users.
    >
    >At the same time, the entire list of online users will be sent out to the
    >current client's online user JInternalFrame.
    >
    >If the user quits the client program, upon detecting the windowClosing
    >method, inside the stop() method, I will write a data stream [LOGOUT,
    >username, ipaddress] back to the server to have this username removed from
    >the server.
    >
    >These two steps are OK for me to write. However, let's say, if the client
    >hangs or ran into some exceptions, the server will need a way to test if the
    >user is still online. So, if the client program do not respond to the
    >request from the server, the server itself will remove the user from the
    >online users list and re-broadcast the current online users list to all
    >other connected clients.
    >
    >How should I go about doing this? Checking for the existence of the client
    >program to see whether it's still 'alive' or not.
    >
    >And, can I keep the online users that contains two fields [username,
    >ipaddress] in a Vector()?
    >
    >How do I write them and how do I retrieve them?
    >
    >Thanks.
    >
    >
    >
    >--
    >
    >
    >
    >Best Regards,
    >Wing Hoe
    >---------------------------------------------------------------
    >ICQ: 2213281
    >Email: winghoe@hotmail.com
    >www: http://pwp.maxis.net.my/winghoe
    >---------------------------------------------------------------
    >
    >
    >
    >
    >
    >


    Message sent from http://www.aewnet.com

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