java-programmer >>Is my socket open?

Is my socket open?

Index ‹ java-programmer

Previous
- 2
  - what's wrong with this thread?Why is it when i create and add a new thread to a vector, the vector,
    instead of adding a new thread, replaces all the old threads with the
    a new one.
    I know it's hard to understand, just run the code below, you'll see
    what i mean.
    
    ////////////////////////////////////////////////
    import java.util.*;
    
    class ThreadTest
    {
    static Vector vec = new Vector();
    
    public static void main(String[] args)
    {
    for (int x=0; x!=10; x++)
    {
    vec.add(x, new TestTrd(""+x));
    ((TestTrd)vec.get(x)).start();
    System.out.println("------------------------------------");
    }
    }
    }
    
    // the thread
    class TestTrd extends Thread
    {
    static String clientName= null;
    
    public TestTrd(String name)
    {
    System.out.println("Original value: "+clientName+" <-- should
    be null");
    clientName = name;
    System.out.println(" New Value: "+clientName);
    }
    
    public void run()
    {
    }
    }
    /////////////////////////////////////////////////////
    
    OUTPUT:
    Original value: null <-- should be null
    New Value: 0
    ------------------------------------
    Original value: 0 <-- should be null
    New Value: 1
    ------------------------------------
    Original value: 1 <-- should be null
    New Value: 2
    ------------------------------------
    Original value: 2 <-- should be null
    New Value: 3
    ------------------------------------
    Original value: 3 <-- should be null
    New Value: 4
    ------------------------------------
    Original value: 4 <-- should be null
    New Value: 5
    ------------------------------------
    Original value: 5 <-- should be null
    New Value: 6
    ------------------------------------
    Original value: 6 <-- should be null
    New Value: 7
    ------------------------------------
    Original value: 7 <-- should be null
    New Value: 8
    ------------------------------------
    Original value: 8 <-- should be null
    New Value: 9
    ------------------------------------
    
    Each time you see a "should be null", it should be null, because a new
    thread is started.
    
    does anybody know what's going on?
- 2
  - Getting access to printDialog attributesI need to print 8 html files. These files are loaded into JEditPanes
    which are then passed to a PrinterJob object. It would be nice to query
    the user with the print Dialog ( printDialog() ) at the beginning of the
    print sequence but not for each successive file. It appears that the
    printDialog() sets a series of attributes in the PrinterJob object. My
    code, on n+1 documents, sets some attributes, but clearly, not all of
    what the printDialog() method sets. And, I have no way of knowing if the
    user changes something (such as page orientation, number of copies,etc).
    Is there a way to get the full PrintRequestAttributeSet out of the
    PrinterJob object so that it can be set for the next print()? I can send
    the code if needed, thanks - Lou
- 3
  - Component requirement
    "David McCallum" <email***@***.com> ha scritto nel
    messaggio news:q3ooc.4353026$email***@***.com...
    > I'm looking for JTextField with a (...) button to the left of it, the idea
    > being a user can type something, the press the button and possibly use
    what
    > was typed in a method. The only thing I can think off calling it is
    > ButtonEdit, then name used in Delphi
    >
    
    In the button_ActionListener you use yourJTextField.getText() to retrieve
    the text present in it.
    
    public void button_ActionListener(ActionEvent e){
    String s=yourJTextField.getText();
    //do whatever you need to do with 's'
    }
- 3
  - Artificial IntelligenceRoedy Green <email***@***.com> wrote in
    news:email***@***.com:
    
    > On Wed, 21 Sep 2005 13:11:14 GMT, "JS" <james.sarjeant90
    @ntlworld.com>
    > wrote or quoted :
    >
    >>But we can fake Intelligence by using hard coded if statements,
    
    [snip]
    
    > I suspect living organisms are the same way. These high level
    > attributes we use to describe humans and their thoughts are just
    > patterns of low level flow. There is nothing in there directly that
    > controls them on that level.
    
    Exactly, there is nothing fake about hard coded if statements, unless
    you want to call everything that is manmade fake.
    
    The problem with hard coded if statements as an implementation of
    intelligence isn't fakeness, it is quality. Unless there are a huge
    number of if statements, you're going to notice pretty quick that this
    intelligence isn't thinking very deeply on a Turing test. It is
    practically impossible to make a good intelligence that way. You would
    probably need billions or trillions of 'if's to make something like a
    human. At the very least you would need to use a computer to write that
    program for you, which is totally violating the spirit of hard coded if
    statements.
- 3
  - Scrolling JPopupMenu"bdinmstig" wrote:
    
    > Actually I'm not surprised because every other post I've seen asking
    > about scrolling a JPopupMenu got no replies, either.
    
    So why do yo go on our nerves? Do you think your problem is so
    important?
    
    > Which begs the question, is there in fact NO solution?
    
    There is. You start from scratch with a JComponent and implement
    everything from groud up. Painting, event handling, everything. Have
    fun.
- 5
  - Accumulated CACMs (since 1966) Considered Dangerous: you want? (free,OfCourse)Newsgroups: comp.unix.solaris,comp.unix.shell
    Subject: Accumulated CACMs (since 1966) Considered Dangerous: you want?
    Summary:
    Followup-To:
    Distribution:
    Organization: PANIX -- Public Access Networks Corp.
    Keywords:
    Cc:
    
    (This is via crosspost -- is faster, easier for me,
    this late; also, all responses visible to me.
    (and, with any luck, you'll see it only ONCE, in ONE
    group -- the *first* one in which you see it)
    
    BE NICE -- DON'T REPLY VIA THE NEWS-GROUP --
    please do it ONLY via EMAIL --
    
    ie, lets keep this crosspost to a SINGLE-article thread.
    
    thanks!)
    
    Yes, dangerous -- I've been informed -- dangerous to the
    continued existence in house of *other* publications.
    
    Feeling a little queasy about getting rid of these things,
    especially the ones up through, say, 1980 (when cacm
    went to hell?) -- anyway, tomorrow is recycled-paper
    pickup day, at maybe 8am they come by with garbage truck --
    
    Anyone want?
    
    You'd have to come by and pick them up yourself.
    
    This is New Rochelle, NY, right on US 95, exit 16,
    maybe 5 miles north of the Bronx.
    
    Interested?
    
    BETTER ACT RIGHT NOW!
    
    If you do reply, please include YOUR PHONE NUMBER.
    
    Thanks,
    
    David Combs
- 6
  - Calling java from the command-line: 40 timesMy company has an ETL that runs 40 'threads', and does logic similiar
    to a Java object I have created. I am trying to convince them to call
    my code instead (from the 40 threads) so we only maintain one code
    base (a BIG issue).
    
    My concern? Sinc eit is a command line program, not a service, each
    'call' will start in it's own JVM - correct? so this machine will
    have 40 JVM's running at the same time? Do I need to be concerned?
    
    What issues am I not considering? The machine is a Solaris box with
    96G of memory and 28 processors. How much overhead does a sinlge JVM
    need?
- 7
  - Diablo 1.3.1 JVM runs out of file descriptors at 1021I'm using the Diablo 1.3.1 JVM package from www.freebsdfoundation.org on a
    4.9-STABLE machine and it unfortunately seems to exhibit the bug described at:
    
    http://developer.java.sun.com/developer/bugParade/bugs/4189011.html
    
    interestingly enough, the linux 1.3.1_02 JVM under a 4.6-STABLE machine does
    not exhibit the problem.
    
    Is there an updated Diablo (diablo-jdk-noplugin-1.3.1.0 Java Development Kit
    1.3.1 is what I'm running) that has this fixed or is my only recourse, other
    than compiling from source, to run under linux emulation?
    
    On the Diablo JVM machine (test.java is the program suggested in the bug
    report):
    
    nine[ttyp2]:aditya~> /usr/local/diablo-jdk1.3.1/bin/java test 3000 1 1 test
    Starting 1078434190431
    
    Opened test0000001020.tst Thread: 0
    test0000001021.tst (Too many open files) java.io.FileNotFoundException:
    test0000001021.tst (Too many open files)
    Aborting 1078434221065
    
    nine[ttyp2]:aditya~> /usr/local/diablo-jdk1.3.1/bin/java -version
    java version "1.3.1"
    Java(TM) 2 Runtime Environment, Standard Edition (build diablo-1.3.1-0)
    Classic VM (build diablo-1.3.1-0, green threads, nojit)
    nine[ttyp2]:aditya~> limit
    cputime unlimited
    filesize unlimited
    datasize 524288 kbytes
    stacksize 65536 kbytes
    coredumpsize unlimited
    memoryuse unlimited
    vmemoryuse unlimited
    descriptors 11095
    memorylocked unlimited
    maxproc 5547
    sbsize unlimited
    
    And the following on a 4.6-STABLE machine running a 1.3.1_02 JVM under linux
    emulation (linux-jdk-1.3.1.02_1 Sun Java Development Kit 1.3 for Linux):
    
    two[ttyp2]:aditya~> java test 3000 1 1 test
    Starting 1078434145154
    
    Closing 1078434235337.tst Thread: 0
    
    two[ttyp2]:aditya~> java -version
    java version "1.3.1_02"
    Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_02-b02)
    Classic VM (build 1.3.1_02-b02, green threads, nojit)
    
    _______________________________________________
    email***@***.com mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-java
    To unsubscribe, send any mail to "email***@***.com"
- 10
  - JavaMail send mail without using default port 25Hi,
    I must send email to a server that listen in port 2025,
    how I can do it using JavaMail??
    
    Thank to all.
    Nicola Trevisan
    
    PS: I insert my code so you can tell me where to place new code.....I hope
    
    props = System.getProperties();
    props.setProperty("mail.transport.protocol", "smtp");
    props.setProperty("mail.host", "127.0.0.1");
    session = Session.getDefaultInstance(props);
    in = new FileInputStream(file);
    msg = new MimeMessage(session, in);
    msg.setFrom(new InternetAddress("email***@***.com"));
    msg.setRecipient(Message.RecipientType.TO, new
    InternetAddress("email***@***.com"));
    transport = session.getTransport();
    transport.send(msg);
- 10
  - Capturing web camera video streamHello gurus,
    Does java have a standard support of web cameras? I'm interested in
    capturing the video stream coming from my webcam using J2SE if this is
    possible.
    Thanks gurus.
- 12
  - Hibernate - one-to-many problem/questionsHi all,
    
    DB: MySQL
    Hibernate 2.0.1
    
    I have a very simple (one-to-many) relationship between two tables
    
    QUESTIONS ANSWERS
    ------------------ ----------------------
    id: long id: long
    text: string qid: long
    text: string
    
    qid is foreign key.
    
    In my Question.hbm.xml I have the following:
    
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD
    2.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
    <hibernate-mapping>
    <class name="my.Question" table="questions">
    <id column="id" name="id" type="long">
    <generator class="identity"/>
    </id>
    <property column="text" length="200" name="text" not-null="true"
    type="string"/>
    <set name="answers" table="answers" lazy="false">
    <key column="qid"/>
    <one-to-many class="my.Answer" />
    </set>
    </class>
    </hibernate-mapping>
    
    There is more than one answer for a question always.
    What happens is when I load a question with answers I only get one answer
    back, though
    in the hibernate trace I see the result set returned more answers and
    objects were initialized.
    
    What is wrong?
    
    I tried to use list instead of set with id as index column, but result was
    N+1 entry. Additional entry was null.
    I still don't understand what should I use as an index column in this case.
    Please help.
    
    thanks in advance,
    Igor
- 12
  - JInternalFrame/JDesktopPane questionHello,
    
    Is it possible to add a JDesktopPane to components other than
    top-level components (RootPaneContainer interface implementors like
    JFrame, JDialog, etc.)? I'd like to contain a set of JInternalFrames
    within one side of a JSplitPane. I don't see a way to do it.
    
    The functionality I'm looking for is a way to create a set of
    components that can be dragged around within one side of a JSplitPane.
    If there is another way to do that outside of JInternalFrames, I'd be
    happy to hear about that as well.
    
    Thanks,
    
    R. Trevor
- 14
  - Problem with loading an image to a PanelSalutations everybody. I want to load an image into a panel. I have
    sub-classed the JPanel class in order to be able to override the pain
    method, like this :
    
    public class ImageCanvas
    extends JPanel {
    Image image;
    public ImageCanvas() {
    super();
    this.setBackground(Color.white);
    }
    public void paint(Graphics g) {
    if (image!=null)
    {
    g.drawImage(image, 0, 0, this);
    }
    }
    public void SetImage(Image img)
    {
    image = img;
    int iW = Math.min(image.getWidth(this),this.getWidth());
    int iH = Math.min(image.getHeight(this), this.getHeight());
    
    this.setSize(iW>>1,iH>>1);
    //this.setSize(image.getWidth(this)>>1,image.getHeight(this)>>1);
    setVisible(true);
    this.repaint();
    }
    
    Now I use this code in order to load my image into a normal jPanel :
    (this is the snippet of code that executes loading the image :
    
    //Display images
    Image img =
    Toolkit.getDefaultToolkit().createImage(strFilePath);//strFilePath of
    course contains the path where the "image.png" is located
    MediaTracker tracker = new MediaTracker(this);
    tracker.addImage(img, 0);
    try
    {
    tracker.waitForAll();
    }
    catch (InterruptedException exI)
    {
    System.out.println("Error while waiting tracker"+
    exI.getMessage());
    }
    jCanvas.setMaximumSize(jPanelImg.getSize());
    jCanvas.SetImage(img);
    jPanelImg.revalidate(); //jPanelImg (type = JPanel) contains
    jCanvas which is of type //ImageCanvas
    jPanelImg.repaint();
    
    However, when I use this program it loads the image all right but the
    background is full of trash. Also if I try to load multiple images
    then they all get jumbled together...
    How can I clean this up ?
    
    Thanx alot !
    Pascal
- 14
  - javax.net.ssl.SSLException: untrusted server cert chain with FireFoxFor an in-house project, I have a web server (Apache) with a
    self-signed certificate. I can access everything via https: just fine.
    The reason for wanting https is to add security to the .htaccess
    passwords. This all works just fine.
    
    FWIW, I'm using FireFox, and simply added the self-signed certificate.
    
    However, no Java applets will load. I get the following when trying
    to load InHouseApp (one of the applets):
    
    load: class InHouseApp not found.
    java.lang.ClassNotFoundException: javax.net.ssl.SSLException:
    untrusted server cert chain
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.a([DashoPro-V1.2-120198])
    [rest deleted]
    
    I have complete access to the various client machines (both desktops
    on the lan, and laptops that will be out in the wild). What do I need
    to add to prevent this exception? Also, as certificates aren't my
    strong suit, are there any step-by-step detail instructions on what to
    do?
    
    TIA
- 15
  - Can't Call Methods in Class Created W/ ReflectionI am testing a class that I'll need later. I need to be able to load one of
    a number of classes that all implement a particular interface, then call 3
    methods in them. When I run the test class, I get the same error
    (indicated in comments below). I've gone over this several times and
    compared it with tutorials online, but I can't find my error (which, the
    way my brain works, means it's probably something simple and obvious and
    I'm just to caught in it to see what's wrong).
    
    The code for the calling class and the called class are below.
    
    Thank you for any help!
    
    Hal
    
    -------------------------------------------------------
    Calling class (ldt):
    
    import java.io.*;
    import java.lang.reflect.*;
    
    public class ldt {
    
    int iCount, iLimit;
    int iSet = 0, iGet = 0, iProcess = 0;
    String dirConf, dirProcess, sName, setFile, RDFile, MMFile;
    String[] fList;
    
    public static void main(String[] args) {
    ldt l = new ldt();
    l.dostuff();
    }
    
    public ldt() {
    
    }
    
    public void dostuff() {
    int i;
    String sTemp = "LDRDMod000";
    Class cSearch = null;
    Object oSearch = null;
    Method[] oMethod = null;
    Method mSet = null, mGet = null, mProcess = null;
    try {
    cSearch = Class.forName(sTemp);
    } catch (Exception e) {
    System.out.println("Error: Could not find class: "+sTemp+", Error: "+e);
    return;
    }
    oMethod = cSearch.getMethods();
    try {
    mSet = cSearch.getMethod("set", new Class[] {String.class,
    String.class});
    mGet = cSearch.getMethod("get", new Class[] {String.class});
    mProcess = cSearch.getMethod("process", new Class[] {});
    } catch (Exception e) {
    System.out.println("Error with getting method. Exception: "+e);
    }
    try {
    oSearch = (Object) cSearch;
    Object[] aInput = new Object[] {(String) "one", (String) "two"};
    Object o = mSet.invoke(cSearch, aInput);
    //Line above seems to be what always causes error, printed below. Error is
    //always: "java.lang.IllegalArgumentException: object is not an instance of
    //declaring class"
    } catch (Exception e) {
    System.out.println("Error: Set Value: "+e);
    return;
    }
    return;
    }
    }
    
    Here is the called class that I'm trying to instantiate through reflection
    (LDRDMod000):
    
    import java.io.*;
    import java.util.HashMap;
    
    public class LDRDMod000 implements LDRDMod {
    
    String sName = "", sStreet = "", sCity = "", sState = "", sZip = "";
    HashMap hData = new HashMap();
    LDConfig sysConfig;
    
    public LDRDMod000() {
    
    }
    
    public void set(String sKey, String sVal) {
    hData.put(sKey.toLowerCase(), sVal);
    return;
    }
    
    public String get(String sKey) {
    String sVal = (String) hData.get(sKey.toLowerCase());
    return sVal;
    }
    
    public void process() {
    String sIn = get("filename");
    String sOut = sIn.substring(0, sIn.indexOf(".RD")) + ".MM";
    File outFile = new File(sOut);
    if (!outFile.exists()) {
    File inFile = new File(sIn);
    // inFile.renameTo(outFile);
    }
    set("filename", sOut);
    return;
    }
    }

Author

Message

Chase Preuninger

Posted: 2008-4-19 1:49:00

Top

java-programmer, Is my socket open? What is the most reliable way to tell if a socket is sill connected?

Peter Duniho

Posted: 2008-4-19 2:03:00

Top

java-programmer >> Is my socket open? On Fri, 18 Apr 2008 10:48:37 -0700, Chase Preuninger
<email***@***.com> wrote:

> What is the most reliable way to tell if a socket is sill connected?

The only reliable way is to try to send something. With TCP, unless the
socket has been closed gracefully (in which case you'll get whatever "end
of stream" indication is appropriate for the class you're using, be that a
return value of -1 or 0 for example), no interruption in the connection
can be detected unless the side that wants to detect the interruption
tries to send something.

I'm tempted to use the same abusive tone here that you've used on others,
but...well, it's only a temptation. I can resist. :)

Pete

Eric Sosman

Posted: 2008-4-19 2:27:00

Top

java-programmer >> Is my socket open? Chase Preuninger wrote:
> What is the most reliable way to tell if a socket is sill connected?

Move some data through it.

--
email***@***.com

Daniel Pitts

Posted: 2008-4-21 2:35:00

Top

java-programmer >> Is my socket open? Eric Sosman wrote:
> Chase Preuninger wrote:
>> What is the most reliable way to tell if a socket is sill connected?
>
> Move some data through it.
>
Specifically, if your application-level protocol supports some sort of
ping/pong handshake, use it as appropriate. You can also have some sort
of time-out, where if you haven't had any activity in /n/ minutes,
assume the connection is dead.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

Index ‹ java-programmer

Next
- 1
  - J2ME: j9 & JSR75?Hi all...
    
    Has anyone tried to install IBM's optional package for JSR75
    support on it's PDA?
    I am having troubles by lauching the Midlet HQ that would
    support FileConnection.
    
    Regards,
    Branko
- 2
  - can't create BufferedImageI am trying to create a BifferedImage and Graphics2D associated with a
    JPanel. I understand that the JPanel must be displayable else the
    createImage method may return null. However in my stub program below I
    always get null returned from createGraphics. I obviously am missing
    something but I can't figure out what. If the program below is run
    without a runline parameter it does not attempt to create a
    BufferedImage and it runs OK. If it is run with a runline parameter it
    throws an exception because bh is null. Why?
    
    Jay
    
    public class Test extends javax.swing.JFrame {
    
    private static String[] opt = null;
    
    public Test() {
    init();
    }
    
    void init() {
    javax.swing.JPanel jContentPane = new javax.swing.JPanel();
    setContentPane(jContentPane);
    setSize(450, 350);
    javax.swing.JPanel graphPanel = new javax.swing.JPanel();
    java.awt.Dimension s = new java.awt.Dimension(400, 300);
    graphPanel.setPreferredSize(s);
    getContentPane().add(graphPanel, null);
    graphPanel.addNotify();
    s = graphPanel.getPreferredSize();
    System.err.println("Is JPanel=" +
    (graphPanel instanceof javax.swing.JPanel) +
    " " + s.width + "x" + s.height + " Displayable=" +
    graphPanel.isDisplayable() + " Headless= " +
    java.awt.GraphicsEnvironment.isHeadless());
    if(opt!=null && opt.length>0) {
    java.awt.image.BufferedImage bh =
    (java.awt.image.BufferedImage)graphPanel.createImage(
    s.width, s.height);
    java.awt.Graphics2D bufh = bh.createGraphics();
    }
    }
    
    public static final void main(String[] argv) {
    opt = argv;
    Test test = new Test();
    test.setVisible(true);
    }
    }
- 3
  - How do I make a simple password field....more.I want to password protect the continued running of a section of javascript.
    
    What I need is for the user to see a login field, they type a code in, if it
    is good, the script continues, if bad, it stops dead.
    I would like to base the password on julian date.
    
    Also, how do I time out a group of statements after a preset amount of time
    like 1 minute or so.
    
    I am not a Java programmer, but if examples are shown, I can usually figure
    out the specific details.
    
    THANKS in advance.
- 4
  - web search with summarized results, good for wireless, too.We just released a wireless search service. The wireless search
    service takes the results returned by Google and gives key points of
    the resulting web sites. The short key points are suitable for viewing
    on wireless devices.
    
    Check it out at:
    http://www.netosprey.com
    
    The following is an example of www.sun.com:
    -----
    
    You entered: http://www.sun.com/
    
    Link to Text ratio: 453/914=0.49562363238512036
    
    AME finds this page has a lot of links.
    It could be an index page and talks about: Java, Sun, System,
    Computing, and Products
    
    Here is a list of main ideas presented in the page:
    
    *** Sun's Big Web Event - Don't miss Network Computing 03-Q4 on
    December 3 at 8 am PST. Sign up for an e-mail reminder today.
    *** Choice on a grand scale. - Sun extends product line through
    strategic alliance with AMD; plans to offer high-performance x86
    systems at affordable prices.
    *** The identity management leader. - Sun's planned acquisition of
    Waveset aims to inject the Java EnterpriseSystem with superior network
    identitycapabilities.
    *** Sun Signs Agreement with CSSC - Java Desktop System to be
    established as the foundation for China's fast-growing IT industry.
    *** Contact |Company Info |Employment |Privacy |Terms of Use
    |Trademarks
    
    -----
    
    Check it out at:
    http://www.netosprey.com
    
    Steve
- 5
  - Adding multiple GUI drivers into one windowHello,
    I'm reasonably new at java:
    I have several classes that create different windows...using JFrame, JPanel
    etc, I was wondering how I could add these seperate gui's to one driver
    class to have it all show in one window (which i could have a tabbed pane)
    
    If someone understands what i'm blabberin about, please help!
    
    --
    Message posted via http://www.javakb.com
- 6
  - question about keeping the GUI and logic separateHello,
    
    I have a question about keeping logic/processing code off of the GUI.
    In a couple of other languages I'm familiar with, there is usually a
    method called FindComponent which will iterate through a form and get
    the component matching the name in the argument.
    
    For example, in VS.NET lets say I have a grid (table) on a form, the
    form represents one class. I then put the code for getting and
    processing data in another class. After any processing occurs (and
    the results are placed in a dataset), I need to bind the dataset to
    the grid. But the grid doesn't have knowledge of where the dataset
    came from... so how does the data get shoveled in there?
    
    In the data processing class, there's a local variable of grid type
    and it's gets bound to the grid in the form, like so (sorry about the
    VB):
    
    Class SomeClass
    Sub doSomething(ByVal c As Component)
    
    Dim localGridView as GridView
    Dim localDataSet as DataSet
    
    ' MyGrid lives on Form1
    localGridView = c.FindComponent("MyGrid")
    
    localGridView.DataSource = localDataSet
    
    ' So even though the GUI hasn't a clue as to what is going on, the
    current data is now displayed to the user.
    localGridView.DataBind()
    
    End Sub
    End Class
    
    Does Java have an equivalent of FindComponent, or a something similar
    to the code snip above?
    
    I'm using Java 6 here. I did try looking at c.getComponent() but
    there's only one valid index... 0 and it represents the
    javax.swing.JRootPane. Anything after 0 throws an index out of bounds
    error. There are 3 JButtons and 1 JList on the panel. I want to add
    some strings to the JList...
    
    public class MyGUI() extends JFrame
    {
    GUIUtils u = new GUIUtils();
    
    public MyGUI()
    {
    //
    // snip
    //
    
    myButton.addActionListener (new ActionListener()
    {
    public void actionPerformed (ActionEvent e)
    {
    try
    {
    u.doSomething(MyGUI.this);
    }
    catch (IOException ioe)
    {
    ioe.printStackTrace();
    }
    }
    });
    }
    
    and...
    
    public class GUIUtils
    {
    public void doSometing(Container c) throws IOException
    {
    listModel = new DefaultListModel();
    
    listModel.addElement(value);
    
    // I want to put the listmodel in the JList now but how do I get
    this code to know about the JList in MyGUI?
    }
    }
    
    Suggestions are greatly appreciated.
    
    Thanks!
- 7
  - a unusual codesthe codes:
    -------------------
    Object[] stuff = new Object[5];
    stuff[0] = "eggs";
    stuff[1] = new StringBuffer( "flour" );
    stuff[2] = 3.56;
    stuff[3] = 'c';
    stuff[4] = 123;
    stuff[0]="33";
    for( int i=0; i<stuff.length; i++ ) {
    System.out.println( stuff[i] );
    }
    ------------------
    It seems odd.....
    
    followings is what I guest. please tell me whether it's correct, thank
    you very much
    
    1:
    what I think is because that the Object Class is any class's
    superClass, so it can point to any type (right?), but in these codes it
    only have Object Class's interface, not the interface which it point
    to.
    is it right?
    
    2:
    stuff[0]="eggs"
    
    in this sentence,the JVM create a String object(right?), although it's
    a String object and of course it has all the String object's
    interface, but what the reference(stuff[0]) can access is only the
    Object Class's interface.not the String interfaces(just like
    concat(),charAt()....)
    is it right?
    
    3:
    stuff[0]="eggs"
    System.out.println( stuff[0] );
    
    and when print it,the print function call stuff[0]'s toString()
    function,and this toString() is the String object's , not the Object
    Class's
    is it right?
    
    thank you very much
    
    JTL
- 8
  - Looping over arrays.Isn't it a waste of resources to loop over arrays this way:
    
    for (i = 0; i < myArray.length; i ++) {
    // do something
    }
    
    ... as opposed to create a variable to hold the value of
    myArray.length first, like so:
    
    int len = myArray.length;
    for (i = 0; i < len; i ++) {
    // do something
    }
    
    This way the length of the array doesn't have to be recalculated on
    every iteration? Or am I completely wrong?
    
    TIA,
    
    AJ
- 9
  - reason for sporadic long full GC pause times?!?....Hello folks,
    
    in our java business application our customer realize sporadic very
    long pauses caused by full gc's.
    Normaly the app runs smoothly with acceptable gc- and
    full-gc-pausetimes. (gc=0.0xx sec / fullgc <=2 sec)
    
    But sometimes during 8 hour work the occurs full gc's with 90-150
    seconds (!)
    which our customer complains about - of course.
    
    In the first step I thought that our JVM-settings were wrong:
    -Xms450m -Xmx450m -XX:NewSize=32m -XX:MaxNewSize=32m
    -XX:SurvivorRatio=8 -classpath....
    --> long full gc pauses occured sporadicaly.
    
    I thought that the Newsize is too small -> wich implies the too big
    tenured space -> which could be the reason for too longs full gc's. I
    decided to use -NewRatio=4 Parameter.
    And I also lowered the max. Heap size to Xmx350m, because the gcviewer
    told me that the memory usage was only about 290 MB.
    
    With the new settings
    -Xms350m -Xmx350m -XX:NewRatio=4 -XX:SurvivorRatio=8 -classpath....
    our customer had the same experience that sometimes the full gc's
    pausetime took more than 100 sec's.
    Additionally we/they relaized that the full gc freed not enough memory
    so that the full gc frequency raised up to a point where no minor gc
    were done - only full gc's !
    
    Due to that I raised Xms and Xmx
    -Xms512m -Xmx512m -XX:NewRatio=4 -XX:SurvivorRatio=8 -classpath....
    which enables the JVM to free more memory at full gc (already tested),
    but I fear this will not help to solve the sporadic problem with the
    long full gc pause times at customer side.
    
    Does anybody have an idea what could be the reason for the
    extraordinary long full gc pause times?
    
    Info btw:
    customer PC's all have 1 GB RAM and the throughput of the application
    was in any case >= 99,8% !
    The problem with the long full gc pause times was never reproduced in
    our lab / dev.-deptmnt.
    
    Thanks in advance
    
    Martin
- 10
  - Ideas, Making a graphical grid look like ISO viewHi, hope my question is not too abstract.
    
    I'm drawing a square grid and I have mouse events that return
    coordinates of that grid. Now I'd like to make that grid look like an
    iso view. Illusion of 3D, seen from an oblique angle, as is typical in
    conquest and exploration games.
    
    Affine transform shear takes me close, but I think it's not going to get
    me all the way. I think the problem is, I don't really want the
    vertical lines to stay parallel, because that makes it look like the
    "far end" is fatter, instead of converging to some vanishing point (The
    squares in the grid should end up being trapezoidal, I think).
    
    So two problems, 1., how to draw my grid in rectangular coords but have
    it look like an iso view, and 2., how to translate the Point from the
    mouse event, into the coordinates of my grid.
    
    If Affine transform is still the way to go, I can keep studying it.
    Right now I'm thinking I may actually need to work out the geometry of
    the iso view, draw it explicitly, and then find the mouse coordinates by
    iterating through the boundaries of my graph. This is nasty, since
    AffineTransforms would make it so easy.
    
    Maybe there's a better way I'm not thinking of, such as, instead of
    bounding my grid by "lines", construct it from "shapes", and then I
    could add a listener to each shape, or something like that. That sounds
    treacherous too.
- 11
  - servlet calling servlet stopped by securityI have two servlets in the same tomcat webapp (A and B) both normally
    accessed from the web. Sometimes A needs to access B and I use http to
    do that. Actually 'B' is about a dozen other servlets, still all in
    the same webapp.
    
    This works just fine until I turn on security constraints. When I do
    that and request A the login form works as normal and invokes A
    correctly. But when A needs to invoke B I get another logon form
    instead of B. This would be okay, I can hack through that, but I only
    know the user name, not the password for A's session.
    
    Is there a simpler way to have one servlet in the same webapp invoke
    another without having to go through security? I cannot just do java
    to java, there are too many entry points (ie cases of 'B') They are
    all volatile and need to be exposed to the web.
    
    Thanks for your help
    Roger
- 12
  - Making hand Hand Held Devices Easier to UseMy partner comes to me every once in a while utterly flummoxed by some
    hand held device for example a cell phone, a wall phone, a stereo, an
    alarm clock (no kidding -- this beast is quite an intimidating device
    it has over 20 buttons), and lately a digital tape recorder.
    
    The problem is these devices have ten thousand features. All she
    wanted to do was place a cell phone call or record a telephone
    interview. The other features just got in the way.
    
    There are two problems:
    
    1. The other features distract from the basics. There are two many
    buttons and too many menu items.
    
    2. The devices have modal traps. Even if you know how to do the
    simple operations, it is easy to hit the wrong button, get off in the
    weeds and not know how to navigate the device back to a familiar
    state.
    
    Imagine a cellphone I could hand to my 4 year old grandson and say
    "hit 7 to call me, hit 8 to call your mother, hit the red button for
    an emergency" Nothing else the child could do would hurt or confuse
    the phone.
    
    Imagine I cellphone I could give to my mother. I say "When you want
    to call make a call, hit the call button, use the up down arrows to
    select a person from your friends list. If you get to the bottom and
    it still not there, choose new person, and they will automatically be
    added to the end of your list, but will drop off automatically
    eventually if you don't call them.
    
    Imagine a digital tape recorder I could give to a child. I restrict it
    so that there are only buttons, record, play, fast forward, rewind.
    you can't overwrite anything recorded. There is no erase button.
    
    Imagine a PDA that starts allowing only the simplest functions.
    Everything else is hidden. Once you have used and apparently mastered
    those functions it offers to teach you yet another function. You can
    decline or ask to lean something else. It never reveals too much of
    its functionality at a time. It remembers the learning state of
    several users.
    
    A few other ideas for hand helds:
    
    1. AC power outlets should have a DC jack built into the wall plate
    using some new style plug that delivers a variety of voltages. The
    tips of the prongs would receive 12, the base 1.5 with perhaps bands
    for 9, 6, 3 in between. The plug on the device would normally only
    tap just one voltage, but it would be free to tap all 5. There would
    be no matching problem. One plug fits all. It would relieve the
    clutter of ac adapters in the typical home office.
    
    2. could it be possible to have a universal charging stand so that you
    can wall mount it and put any device in it for a recharging by
    induction. Another feature of the charging stand is it would also
    tell and device in it the latest accurate atomic time. You could then
    create a "wand" you recharge with the correct time then wave at the
    microwave or any other non-portable device to update its clock.
    
    3. Could every product be given a UPC number or equivalent so that you
    can find an online manual for any device without fuss. Software too
    should get such numbers so you can automatically track the latest
    version, the replacement or the author. Software then could keep
    track of your possessions (software and otherwise) and periodically
    poll for a recall message, an important update etc.
    
    --
    Bush crime family lost/embezzled $3 trillion from Pentagon.
    Complicit Bush-friendly media keeps mum. Rumsfeld confesses on video.
    http://www.infowars.com/articles/us/mckinney_grills_rumsfeld.htm
    
    Canadian Mind Products, Roedy Green.
    See http://mindprod.com/iraq.html photos of Bush's war crimes
- 13
  - jboss and Workflow??I'm work with Jboss, and I'd use Workflow on Jboss server. Is Anyone working about this problem? Can anyone give me a tutorial or an example???
- 14
  - Integrating servlet container into my stand alone AppHello Everyone,
    
    I had this idea for an application I would like to write. I want
    to write it as a java application, but be able to output
    program-generated .html into an Internet Explorer window. Sending the
    generated html to the IE window is easy... just using the Runtime
    class. But I want the Internet Explorer window to be able to make http
    calls back to my application for form submissions. I didn't want to
    have to force my users to install Tomcat just so the internet explorer
    could pass back information to the servlet in my .Jar file.
    
    How hard is it to add a servlet container and respond to http post's
    from the localhost internet explorer window? This is all from my .jar
    file and not from a web application running under tomcat remember. The
    only http requests coming into my application will be from that one
    internet explorer window... so its really acting like a
    single-user-local-machine Tomcat server. But I dont want the burden of
    forcing Tomcat on people.
    
    I suppose you'll say pick a standard application or a jsp/servlet
    solution, but not both.... but I think there is a lot of flexability
    to this method, being able to generate GUI screens on the fly in the
    IE window is really exciting.
    
    Thanks,
    
    Greg
- 15
  - Comparing two long numbersOn Mon, 2 Jun 2008, Daniele Futtorovic wrote:
    
    > On 2008-06-02 13:22 +0100, Lew allegedly wrote:
    >> Lew wrote:
    >>>> Why do you use either "d" or "D"? Is it something you always put on
    >>>> double constants, or just for potentially ambiguous situations? If the
    >>>> latter, how do you assess ambiguity?
    >>
    >> John B. Matthews wrote:
    >>> I don't use either "d" or "D"; I use "d", but I have to read other
    >>> people's "D"s. Presbyopia comes to us all. :-)
    >>
    >> Most people don't bother with either "d" or "D" in Java double constants.
    >> I never have to read other people's "D" in Java code; I don't think I've
    >> ever encountered a double suffix on a constant in any professional Java
    >> code.
    >
    > double athird = 1d / 3; ?
    
    Urgh. Now this:
    
    double farthing = 1d / 4 ;
    
    is at least numismatically accurate, but won't compile after 1960!
    
    tom
    
    --
    Eat whip you steroid wall-bashing lug-head! -- The Laird