| Integrating servlet container into my stand alone App |
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Index ‹ java-programmer
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- 1
- 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?
- 2
- 2
- 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"
- 3
- 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
- 5
- 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);
- 5
- 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
- 5
- 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
- 5
- 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
- 8
- 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
- 9
- 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
- 9
- 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'
}
- 12
- 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;
}
}
- 14
- 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.
- 16
- 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
- 16
- 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.
|
| Author |
Message |
gregfrommer
|
 Posted: 2004-9-26 2:42:00 |
Top |
java-programmer, Integrating servlet container into my stand alone App
Hello 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
|
| |
|
| |
|
Silvio Bierman
|
| Posted: 2004-9-26 8:20:00 |
Top |
java-programmer >> Integrating servlet container into my stand alone App
"DiscoStu" <email***@***.com> wrote in message
news:email***@***.com...
> Hello 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
Greg,
My company supplies a software system that is basically based on standard
servlets but since most of our potential customers do not own or want to own
a J2EE server environment we normally distribute our servlets packages with
a servlet container that can be simply embedded in a Java app (of no more
then a few lines). In short, people only install a JRE, unpack our ZIP and
fire up the app. For windows environments we cooked up a service wrapper EXE
and that is it.
Actually, our system consists of a central server that has no user
interfaces but handles XML requests through HTTP (servlets handle the
requests through the servlet container) which come from multiple application
servers (servlets that generate HTML as the UI and connect to the central
server via HTTP requests). Both tiers are servlet based and use the same
setup.
The embeddable server is Jetty (www.mortbay.org) which is one of the best
(free) servlet containers available and very simple to embed (including
sample code and great free support through the mailing lists).
|
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gregfrommer
|
| Posted: 2004-9-27 11:41:00 |
Top |
java-programmer >> Integrating servlet container into my stand alone App
> The embeddable server is Jetty (www.mortbay.org) which is one of the best
> (free) servlet containers available and very simple to embed (including
> sample code and great free support through the mailing lists).
That sounds exactly like what I need. Thanks for pointing it out.
|
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Index ‹ java-programmer |
- Next
- 1
- For loop not working from static methodI have a JSP that outputs 10 links and it works great but want to cut
down on the scriptlet lines in my JSP.
Now I want to put the for loop that outputs the 10 links into a source
file and call the class in my JSP using just one line scriptlet.
Here is what my current JSP looks like where it outputs the 10 links:
<jsp:useBean id="pageinfo" class="storm.Pageinfo" scope="session" />
.....
<%
if (pageinfo!=null)
{
for(int i=0;i < 10;i++)
{
out.println("<a href=moveto.jsp?inpage=" + i + ">" + i + "</
a>");
}
}
%>
Now my attempt to put it in a class outputs only 1 link instead of 10.
Source code for the Java class:
package storm;
import storm.*;
public class PageUtil
{
public static String theMethod(Pageinfo pageinfo)
{
if (pageinfo!=null)
{
for(int i=0;i < 10;i++)
{
return "<a href=moveto.jsp?inpage=" + i + ">" + i +
"</a>";
}
}
return "";
}
}
JSP scriptlet calling the static method:
<%= PageUtil.theMethod(pageinfo) %>
Please advise how I can get this to work. I am using Tomcat 4.1.27
and dont have JSTL.
- 2
- 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.
- 3
- 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
- 4
- J2ME, How to minimize a program ?Thank you so much for the information I didn't know.
But, for Sony Ericsson cells, we can press back button ( like the
symbol of inverse Enter ) to exit ( not destroy ) program.
For SmartPhone - P910i, we can run other funtion very easily ( we don't
have to implement it )
I found a cheat method that could do this.
public Form f;
....
....
// Do not new a Form for f
display.setCurrent(f); // minimum program :p
// I don't know why, the compiler pass it, and we can find it is work
on cell.
- 5
- 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???
- 6
- panel question.."Frances" <email***@***.com> wrote in message
news:4317337c$0$18646$email***@***.com...
<snipped />
> Sunde, we finally managed to connect to server.. thank you very much for
> all your help, very much appreciated.. Frances
You never said...
Did your original code call one of the applets methods from JavaScript?
...or was it something else?
I'm just curious to what was wrong...
--
Dag.
- 7
- 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!
- 8
- 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
- 9
- 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
- 10
- GridBagLayout and JMenuBar problemsHere's another interesting one. I looked on the Bug Parade to see if
this was present, but rapidly drowned in the sea of totally unrelated
results I got back from the brain dead search capabilities.
I built up a JPanel using GridBagLayout and various components. Works
fine; I'm quite used to GridBagLayout and its quirks. I'm using the
Java look and feel with native decorations turned off, so GridBagLayout
respects my panel's minimum size constraints.
I had been testing this layout in a JFrame without a JMenuBar, just to
validate the layout. Now when I added a JMenuBar to the JFrame, the
layout screws up when I resize the panel down to its smallest size.
It's as though the GridBagLayout does not take the JMenuBar's dimensions
into account when resizing happens. In my case, a couple of buttons
shrink in height, a text field bizarrely grows to 1.5X height, and
another text field overlaps it. None of these problems show up unless
the menu bar is in place.
Again: a known bug? Or should I submit it?
If there's any interest I'll whittle my code down to a SSCCE. Then I'll
try it with native window decorations turned on to see if that's where
the problem lies.
Laird
- 11
- 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
- 12
- 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
- 13
- 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.
- 14
- 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);
}
}
- 15
- 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
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