| paintComponent into a BuffereImage? |
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Index ‹ java-programmer
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- 1
- Doing one last thing to a WeakReferenceLew wrote:
> Paul J. Lucas wrote:
>> Lew wrote:
>>>
>>> This is not a flaw in Java.
>>
>> Yes it is.
>
> No, it isn't.
Real compelling argument there. Java programmers need to stop being in denial
and admit that Java has flaws just like every other language.
- Paul
- 1
- AffineTransform.getScaleInstance questionHi,
I am using the AffineTransform.getScaleInstance to transform an image
by showing it growing. i.e. something like the following:
while(scale <= 1) {
repaint();
scale += 0.05;
try {
Thread.sleep(25);
}
catch(InterruptedException e) {
e.printStackTrace();
}
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setComposite(AlphaComposite.SrcAtop);
g2.transform(AffineTransform.getScaleInstance(scale, scale));
g2.fill(clipShape);
g2.dispose();
}
the problem is that the image grows large from the top lefthand corner
towards the bottom right hand corner.
What I want is the image to grow from the bottom left hand corner to
the top right hand corner.
I have tried messing with the Scale instance, but I cant seem to figure
it out.
anyone know how to do this? thanks!
- 2
- A specific external package import from javacWhich file(s) are required?
Where should these file(s) go?
What's the javac syntax to compile Test16 into ...\class\?
Given this directory structure:
C:\java\java\jTidy\Test16.java
C:\java\org\w3c\
C:\java\class\
Given that Test16.java has this import:
import org.w3c.tidy.Tidy;
SSCE @ <http://thufir.lecktronix.net/java/Test16.java>
Here's what I've gleaned from the 'net:
C:\java> javac -d . org\w3c\* C:\java\java\*
Clearly not correct, but that's my best effort at this point :(
thank you,
Thufir Hawat
- 3
- JTree with dynamically adjusted row height during editing.I have extended JTable so that the installed editor for a cell checks
at each keystroke whether it must adjust the row height in order to fit
the content in the cell. This is easy to do with a document listener
which just starts a thread on each insertion to check for a height
change, and then calls setRowHeight on the appropriate row.
However, it does not seem to be so simple to do the same thing with a
JTree. setRowHeight cannot be called on a specific row, and with
rowHeight set to 0, the tree cells are only resized when the tree
manager itself queries the height. There does not appear to be a way
to get the editor to do this directly.
Does anyone know how to get this effect? It allows for something much
like a regular text outliner using JTree and I would think lots of
people would have wanted to do this in the past, but I havent found
evidence that it has been done.
- 5
- JNI: call C-main program from JavaI have a C-program which calls Java functions through JNI.
The C-part runs okay, and I want to debug the Java code.
For that reason, I want to start the Java debugger and then start the
C-main program through JNI. After that I hope I can set
breakpoints within the Java part and start debugging.
In the documents I saw that "System.LoadLibrary()" can load
only DLL's and shared object, but no main-program.
Thanks for any help,
Josef
- 5
- memory profiler recommendationJavameisters,
I have written an application for J2SE using the Netbeans IDE. I would
like to test it for memory leaks before releasing it, and would like a
recommendation as to what to use. I tried OptimizeIt some time ago,
and it seemed to do what I want, but I was just wondering if there are
better (or less expensive) alternatives.
Thanks much,
Matthew Fleming
email***@***.com
(please remove X before using this address)
- 7
- AES-RijndaelI am doing an entry in the Java glossary on AES aka
Rijndael symmetric cipher.
I wonder if anyone knows of opensource Java implementations.
see http://mindprod.com/jgloss/aes.html
for what I have discovered so far.
--
Canadian Mind Products, Roedy Green.
Coaching, problem solving, economical contract programming.
See http://mindprod.com/jgloss/jgloss.html for The Java Glossary.
- 8
- Improving hashCode() to match equals()In my NamedBitField class I define equals() to mean that 2
NamedBitFields are equal if all 3 of their fields are equal.
Any suggestions for improving my hashCode() definition? I
can improve its performance by caching the computed hashCode
in a transient field, sure, but can I improve the _way_ it's
computed?
class NamedBitField {
String name; // name of bit field
int startIndex; // where it starts
int length; // how many bits it occupies
pubic boolean equals(Object obj) {
if (this == obj)
return true;
if ( obj == null || this.getClass() != obj.getClass() )
return false;
NamedBitField other = (NamedBitField) obj;
return
this.name.equals(other.name) &&
this.startIndex == other.startIndex &&
this.length == other.length;
}
public int hashCode() {
// to make this symmetric with equals() I'd prefer to
// involve all 3 fields (name, startIndex and length)
// in the computation of the hash. But how?
//
// Here I'm simply reusing String.hashCode(), but the
// hashed String at least incorporates the other
// fields
return ((name + startIndex) + length).hashCode();
}
}
Marco
----------------------------------------------------
Please remove digits from e-mail address (tr/0-9//d)
- 8
- Java proxy server for IEHi,
I hope someone can help me (I am an inexperienced Java programmer).
What I'm trying to do is write a Java Application that acts as a proxy
server for Internet Explorer. The goal of the little Java application
is to be able to log HTTP requests and responses between IE and a web
server.
I've pasted my application as it exists so far. It only handles HTTP
GETs right now, which is fine for my purposes at the moment. It works
for simple HTML pages. The problem is that I can't get it to
read/write graphic information correctly, such as when a web page
requests a gif (the graphic appears messed up in IE). I have 2
questions for all the Java experts out there:
(1) How can I handle binary content so it's properly rendered in the
browser.
(2) Using writeBytes from the DataOuputStream class seems to write one
byte at time, even though I'm passing in a string. I'd like a method
that writes in batches to the socket endpoint. Is that possible?
Thanks for any and all help!
import java.io.*;
import java.net.*;
class SimpleProxy {
public static void main(String[] args) {
ServerSocket ss = null;
Socket s = null; // client socket connection with client (browser)
DataOutputStream os = null; //client (browser) output;
DataInputStream is = null; //client (browser) input
String sInput;
int iPosURLEnd;
String sURL;
Socket sServ = null; //client socket connection with server (web
server)
DataOutputStream osServ = null; //server (web server) output;
DataInputStream isServ = null; //client (web server) input
int iPosHostStart;
String sHost;
System.out.println ("Starting app...\r\n");
try {
ss = new ServerSocket(45678);
}
catch (Exception e) {
System.out.println ("Error establishing ServerSocket
connection.\r\n");
System.out.println ("Error: " + e.getMessage());
}
for (; ;) {
try {
s = ss.accept();
System.out.println("Connection established.\r\n");
os = new DataOutputStream(s.getOutputStream());
is = new DataInputStream(s.getInputStream());
}
catch (Exception e) {
System.out.println ("Error establishing connection.\r\n");
System.out.println ("Error: " + e.getMessage());
}
System.out.println("--------- Read REQUEST from client
--------\r\n");
for (; ;) {
try {
sInput = is.readLine();
if (sInput == null)
break;
System.out.println("Client: " + sInput);
if (sInput.startsWith("GET",0)) {
iPosURLEnd = sInput.indexOf(" ",4); // 4 = Len("GET ")
sURL = sInput.substring(4, iPosURLEnd);
iPosHostStart = sURL.indexOf("://") + 3; // 3 = Len("://")
sHost = sURL.substring(iPosHostStart,
sURL.indexOf("/",iPosHostStart+1));
try {
sServ = new Socket(sHost, 80); //assume port 80
osServ = new
DataOutputStream(sServ.getOutputStream());
isServ = new DataInputStream(sServ.getInputStream());
}
catch (Exception e) {
System.out.println ("Error establishing connection with
server.\r\n");
System.out.println ("Error: " + e.getMessage());
}
}
osServ.writeBytes(new String(sInput + "\r\n"));
if (sInput.compareTo("") == 0)
break;
}
catch (Exception e) {
System.out.println ("Error reading information from
client.\r\n");
System.out.println ("Error: " + e.getMessage());
}
}
System.out.println("--------- Write RESPONSE from server
--------\r\n");
for (; ;) {
try {
sInput = isServ.readLine();
if (sInput == null)
break;
System.out.println("Server: " + sInput);
os.writeBytes(new String(sInput + "\r\n"));
}
catch (Exception e) {
System.out.println ("Error reading information from
server.\r\n");
System.out.println ("Error: " + e.getMessage());
}
}
try {
isServ.close();
osServ.close();
sServ.close();
is.close();
os.close();
s.close();
}
catch (IOException e) {
System.out.println ("Error closing sockets.\r\n");
System.out.println ("Error: " + e.getMessage());
}
}
}
}
- 10
- JSP, forward, include, dispatch rules ?Can I get a clear summary of the rules involved with these ?
forward, include, RequestDispatcher rd
<jsp:include page="servlet/MyServlet" flush="false" />
rd.forward(req, res);
<jsp:forward page="NextPart.jsp" />
response.sendRedirect("NewPage.html");
What I have seen, is that this Error occurs:
'IllegalStateException: Cannot forward after response has been
committed'
When a JSP/Servlet writes to the page using a PrintWriter and then
tries to do a forward.
Maybe the following also cause problems:
response.setContentType(...)
response.setHeader(...)
TIA for your help, suggestions; Please Advise.
- 11
- Struts JDO EJB Hibernate JFC - NUTS !The industry is in pure and utter chaos.
So many choices. How does one know which one is the popular one?
Is it Struts? Is it JFC? Is EJB unpopular (bloat)?
Personally, I find that xdoclet makes writing EJB's a total breeze,
dealing with the database that is. Are people using JDO now, or have
people been looking to see what JDO is all about but can't find any
solid examples so that people can't get rolling with it?
For the webgui, I wish more solutions would take the XMLC (enhydra) or
Tapestry approach. JSP / JSF / Struts all fail to separate design
from content.
Which framework handles form processing best? When I tried Struts I
lost days and days dealing with the uninformative errors it spits out.
Which one is better? What do people like these days? Or is everyone
else also in disarray, and keeps browsing site after site after blog
after blog and can't seem to get the scoop anymore?
- 13
- M-I 5-Persecution . my resp onse to the harass ment-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-= my response to the. harassment -=
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
My first reaction in 1990/91 was to assume that. if I broke contact then
they would not be able to follow and would lose interest.. So I did the
things that have been suggested by other people; I sold my. television,
stopped listening to the radio and tried. to withdraw away from the sources
of abuse as much as possible. I reasoned that. they must have more important
things. to deal with and that normal people would simply leave me alone if
it. were made difficult for them to continue their harassment.
I reckoned without the sheer vindictiveness of the abusers. They. did not
let up. but instead "got to" people around me, mainly people at work, to do
their dirty work for them. I went to see my GP, who refused to. believe what
he was being told, and. refused to direct me on to anyone who could be of
practical assistance. It was not until three. years had passed that the GP
admitted the matter was. outside his competence and suggested going to the
police.
In the summer of 1994 we called in. counter-surveillance experts from a
private detective agency to sweep our house and telephone for. bugging
devices. They conducted. a thorough search and found nothing; but as noted
above, since the existence of surveillance was being. forced in my face by
the harassers, you would expect. them to have taken the possibility of a
counter-surveillance sweep into account when. planning the type of devices
to. be employed.
In Easter 1995 I made a complaint to. my local Police station in London, but
the police have not expressed any intention to do anything about. the
continuing harassment ("we're not saying it's. happening and we're not
saying it isn't. happening" were the words used). I think the officer I
spoke to at Easter wasn't aware of it happening, although other members. of
the police force obviously do. know.
From April 1995 until the present time the. matter has been discussed in a
lot of detail on the Usenet (Internet) "uk.misc" newsgroup.. That discussion
has. given birth to the article which you are now reading. My hopes in
posting to Usenet were that. wider publicizing would discourage the security
services from continuing their harassment, and "draw. people out" into
concurring with the truth of what was being said. Neither of. those have
followed, but the discussion has served a purpose in allowing. this
structured. report to be created.
8322
- 13
- McNealy should have watched "Godfather 3" -- "Never hate your enemies, it clouds your judgement.""The worst thing about this deal is that Sun brought it upon itself
through a campaign of ridicule and hate promulgated personally by CEO
Scott McNealy. This is McNealy's failure and nobody else's. The quotes
last week from McNealy were laughable, the about face nothing short of
shameful. How are Sun's big customers going to believe what the company
says in the future in the face of such a change? How can they base huge
technical investments on the word of Sun?"
Answer: They can't. They never could.
http://www.pbs.org/cringely/pulpit/pulpit20040408.html
- 16
- 16
|
| Author |
Message |
fiziwig
|
 Posted: 2006-8-10 6:27:00 |
Top |
java-programmer, paintComponent into a BuffereImage?
It seems like I should be able to override the paintComponent method of
a class and have it do its paint into a BufferedImage something like
this:
public void paintComponent(Graphics g) {
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2D = image.createGraphics();
super.paintComponent( g2D );
.. etc ...
But all I get is a null pointer exception on super.paintComponent( g2D
); even though g2D is definitely NOT null. The exception actually comes
deep in the bowels of Java at:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.awt.Rectangle.intersects(Unknown Source)
at javax.swing.text.BoxView.paint(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$RootView.paint(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI.paintSafely(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI.paint(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI.update(Unknown Source)
at javax.swing.JComponent.paintComponent(Unknown Source)
at TextPanel.paintComponent(TestClass.java:139) <--- the
super.paintComonent()
Any ideas on how to make this work?
Thanks,
--gary
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Thomas Fritsch
|
| Posted: 2006-8-10 8:15:00 |
Top |
java-programmer >> paintComponent into a BuffereImage?
fiziwig" <email***@***.com> wrote:
> It seems like I should be able to override the paintComponent method of
> a class and have it do its paint into a BufferedImage something like
> this:
>
> public void paintComponent(Graphics g) {
>
> BufferedImage image = new BufferedImage(width, height,
> BufferedImage.TYPE_INT_RGB);
> Graphics2D g2D = image.createGraphics();
> super.paintComponent( g2D );
>
> .. etc ...
Be aware that paintComponent() may be called hundreds of times per second,
depending on what you do with your GUI (moving it, maximizing it, resizing
it, ...). It is therefore not a good idea to create a new BufferedImage each
time, and paint on it.
>
> But all I get is a null pointer exception on super.paintComponent( g2D
> ); even though g2D is definitely NOT null.
Correct.
> The exception actually comes deep in the bowels of Java at:
>
> Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
> at java.awt.Rectangle.intersects(Unknown Source)
The NullPointerException occurs inside Rectangle's method
intersects(Rectangle rect) probably because the rect passed in is null. You
may want to look into Sun's source 'Rectangle.java' (you'll find it in
'src.zip' which is part of the JDK installation).
> at javax.swing.text.BoxView.paint(Unknown Source)
> at javax.swing.plaf.basic.BasicTextUI$RootView.paint(Unknown Source)
> at javax.swing.plaf.basic.BasicTextUI.paintSafely(Unknown Source)
> at javax.swing.plaf.basic.BasicTextUI.paint(Unknown Source)
> at javax.swing.plaf.basic.BasicTextUI.update(Unknown Source)
> at javax.swing.JComponent.paintComponent(Unknown Source)
> at TextPanel.paintComponent(TestClass.java:139) <--- the
> super.paintComonent()
>
> Any ideas on how to make this work?
I don't know what exactly you want to achieve. I assume you are just curious
and want to grab a snapshot of your TextPanel, to see if it works.
Don't override paintComponent(), but call paint() directly once after your
panel has got visible:
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2D = image.createGraphics();
yourTextPanel.paint(g2D);
You don't call paintComponent(), but call paint(), because that will draw
the whole component (including its border, its children, and the component
itself). You may want to look into the source 'JComponent.java', to see what
paint() actually does.
--
Thomas
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fiziwig
|
| Posted: 2006-8-11 0:45:00 |
Top |
java-programmer >> paintComponent into a BuffereImage?
Thomas Fritsch wrote:
> fiziwig" <email***@***.com> wrote:
> > It seems like I should be able to override the paintComponent method of
> > a class and have it do its paint into a BufferedImage something like
<snip>
> Be aware that paintComponent() may be called hundreds of times per second,
> depending on what you do with your GUI (moving it, maximizing it, resizing
> it, ...). It is therefore not a good idea to create a new BufferedImage each
> time, and paint on it.
> >
<snip>
> >
> > Any ideas on how to make this work?
> I don't know what exactly you want to achieve. I assume you are just curious
> and want to grab a snapshot of your TextPanel, to see if it works.
<snip>
> --
> Thomas
Thanks for that warning about the frequency of paintComponent(). That
will obviously not be satisfactory.
My purpose is that, out of desperation, I'm trying everything possible
to rotate a JTextPane by 90 or 180 degrees. I've tried at least two
dozen different ways to do it. The most straightforward way, to apply
an AffineTransform to the JTextPane simply doesn't work correctly, even
though it DOES work on other components such as JLabels, etc. On the
JTextPane the text rotates, but the clipping is all messed up and I
haven't found any way to get it to work correctly.
All I want to do is to display the contents of a JTextPane, in
non-editing mode, rotated 90 or 180 degrees, and as far as I can tell,
Java just isn't capable of doing that. Either that or the JTextPane +
AffineTransform combination has some serious unfixed bugs.
I can't use a JLabel (which I CAN rotate) because I need the text to
retain its attributes like font, bold, size, etc. and a JLabel can't do
that.
Any ideas?
--gary
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fiziwig
|
| Posted: 2006-8-11 4:50:00 |
Top |
java-programmer >> paintComponent into a BuffereImage?
Thomas Fritsch wrote:
> fiziwig" <email***@***.com> wrote:
> > It seems like I should be able to override the paintComponent method of
> > a class and have it do its paint into a BufferedImage something like
> > this:
> >
> > public void paintComponent(Graphics g) {
> >
> > BufferedImage image = new BufferedImage(width, height,
> > BufferedImage.TYPE_INT_RGB);
> > Graphics2D g2D = image.createGraphics();
> > super.paintComponent( g2D );
> >
> > .. etc ...
> Be aware that paintComponent() may be called hundreds of times per second,
> depending on what you do with your GUI (moving it, maximizing it, resizing
> it, ...). It is therefore not a good idea to create a new BufferedImage each
> time, and paint on it.
FWIW: I solved the problem like this:
class TextPanel extends JTextPane {
// implements rotation for a JTextPane
private int rotation;
private int tx, ty;
private int wide, high;
private BufferedImage renderedText = null;
// valid rotation values are:
// 0 = no rotation
// 1 = rotation 90 degree clockwise
// 2 = rotation 180 degrees
// 3 = rotation 90 degrees counterclockwise
TextPanel() {
super();
rotation = 0;
tx = 0;
ty = 0;
}
public void setDefaultBounds( int x, int y, int width, int height)
{
high = height;
wide = width;
super.setBounds(x,y,width,height);
}
public void setRotation( int newRotation ) {
newRotation = newRotation % 4;
if ( rotation != newRotation ) {
switch (newRotation) {
case 0 : tx = 0; ty = 0; break;
case 1 : tx = 1; ty = 0; break;
case 2 : tx = 1; ty = 1; break;
case 3 : tx = 0; ty = 1; break;
}
if ( newRotation != 0 ) {
if ( renderedText==null) {
rotation = 0; // so that text is actually rendered
renderedText = new BufferedImage(wide, high,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2D = renderedText.createGraphics();
paint( g2D );
}
}
rotation = newRotation; // so the repaint will paint the
rendered image
if ((rotation%2)==0) {
setSize(wide,high);
} else {
setSize(high,wide);
}
repaint();
}
}
public int getRotation() { return rotation; }
public void paintComponent(Graphics g) {
if ( rotation == 0 ) {
super.paintComponent(g);
return;
}
Graphics2D g2 = (Graphics2D) g;
double angle = rotation * Math.PI/2;
AffineTransform tr = g2.getTransform();
if (rotation==2) {
tr.setToTranslation(wide*tx,high*ty);
} else {
tr.setToTranslation(high*tx,wide*ty);
}
tr.rotate(angle);
g2.drawImage(renderedText, tr, this);
}
}
--gary
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Index ‹ java-programmer |
- Next
- 1
- Confused with the ArrayListHello,
ArrayList main = new ArrayList();
ArrayList copy = new ArrayList();
copy.add("Test1");
copy.add("Test2");
main.add(copy);
copy = new ArrayList();
copy.add("Test3");
copy.add("Test4");
main.add(copy);
for(int i=0;i<main.size();i++)
{
ArrayList temp = (ArrayList)main.get(i);
for(int j=0;j<temp.size();j++)
{
System.out.println(temp.get(j));
}
}
for(int i=1;i<main.size();i++)
{
ArrayList temp = (ArrayList)main.get(i);
temp.set(0,"Test5");
temp.set(1,"Test6");
}
for(int i=0;i<main.size();i++)
{
ArrayList temp = (ArrayList)main.get(i);
for(int j=0;j<temp.size();j++)
{
System.out.println(temp.get(j));
}
}
}
- 2
- 3
- JDK 1.5 and J2EE?I have bravely set up JDK 1.5 on one of my systems, which works a
treat. The trouble I'm having is with using it for J2EE applications.
I've tried dropping j2ee.jar into lib/ext so I can get at Servlet
and so on, but then I get another problem...
I use TransformerFactory.newInstance(), and I get a "class not found"
exception for org.apache.whatever.Transformer (which JDK 1.4 used)
rather than com.sun.org.apache.whatever (as per JDK 1.5). I presume
that the TransformerFactory is coming from j2ee.jar rather than the
1.5 library for this to happen...?
So: I want to be able to rebuild (and improve!) a load of code using
1.5, and I can do this for most things; servlets recompile fine, as
do various other apps, but I seem to have a choice between leaving
all my servlets on 1.4 (and removing j2ee.jar from 1.5) or leaving
my XML stuff on 1.4 (which I don't want to do, because I want some
of the 1.5 enhancements).
Any suggestions? Am I being stupid again?
-----------------------------------------------------------------
John English | mailto:email***@***.com
Senior Lecturer | http://www.it.bton.ac.uk/staff/je
School of Computing & MIS | ** NON-PROFIT CD FOR CS STUDENTS **
University of Brighton | -- see http://burks.bton.ac.uk
-----------------------------------------------------------------
- 4
- Howto read newline characterHi,
I'm new to java and I'm writing a simple text editor using swt examples
from eclipse. The only problem I see is that my editor wont display the
text file correctly. It will display the whole text file in one line.
Here is the code I use to open file. I don't know where to start.
public class OpenFile extends SelectionAdapter {
public void widgetSelected(SelectionEvent event) {
FileDialog fileOpen = new FileDialog(shell, SWT.OPEN);
fileOpen.setText("Open");
String[] filterExt = { "*.txt", "*.ini", "*.*" };
fileOpen.setFilterExtensions(filterExt);
String selected = fileOpen.open();
if (selected == null) {
return;
}
FileReader file = null;
try {
file = new FileReader(selected);
} catch (FileNotFoundException e) {
MessageBox messageBox = new MessageBox(shell, SWT.ICON_ERROR | SWT.OK);
messageBox.setMessage("Could not open file.");
messageBox.setText("Error");
messageBox.open();
return;
}
BufferedReader fileInput = new BufferedReader(file);
String textString = null;
StringBuffer sb = new StringBuffer();
try {
do {
if (textString != null) {
sb.append(textString);
}
} while ((textString = fileInput.readLine()) != null);
} catch (IOException e1) {
MessageBox messageBox = new MessageBox(shell, SWT.ICON_ERROR |
SWT.OK);
messageBox.setMessage("Could not write to file.");
messageBox.setText("Error");
messageBox.open();
return;
}
text.setText(sb.toString());
}
}
Thanks in advance,
C
- 5
- Correct use of ReadableByteChannelFor a piece of code intented to be rather
generic, I thought it would be a good idea
that it reads its input from a
ReadableByteChannel. The main reason to
choose it over an InputStream was that the
channel can be obtained for an InputStream as
well as for a RandomAccessFile.
Now the question:
How do you correctly perform a blocking read
from a ReadableByteChannel given that it does
not necessarily block?
I came up with
ReadableByteChannel source;
ByteBuffer inBuf;
...
int result;
while( 0==(result=source.read(inBuf)) ) Thread.yield();
In case the channel is blocking, the yield()
will never be called. If the channel is
non-blocking, the yield() may be called. But
on a machine without much load, I am afraid
it will generate load because no other thread
is interested in the processor.
Any ideas how this can be done better?
Harald.
- 6
- 7
- [Active Tags] Have the RefleX !hi,
People that are intersting in native XML programming can download the
RefleX engine freely here :
http://reflex.gforge.inria.fr
RefleX is available under the french license CeCILL, which is almost the
same as the well-known GNU GPL.
RefleX is a Java tool that allows people that have no particular
knowledge of Java to write smart programs entirely in XML ; however, the
most brave fellows could also design their own tags and plug them to the
engine ! Have a look at the "How-To" section to achieve this.
The concepts of native XML programming used in RefleX have been designed
separately, so that other implementations on other platforms/languages
can be considered.
Why programming in XML ?
At INRIA, we have experienced RefleX on a *real* operational project,
and it appears that :
-the code is very easy to produce
-the amount of code produced is very tiny
Despite the intrinsic verbosity of XML, the expressiveness of XPath
(which is used intensively in Active Tags) and the ability to declare
complex processes exposed as simple tags makes Active Tags programs very
efficient.
Active Tags has been designed like a programming language : it offers
several libraries (called modules) for different purpose : system
interactions, I/O, SQL, Web, etc and allow users to define simply their
own libraries, but Active Tags differs from other programming languages
in many ways... read more on the Active Tags website or on the RefleX
web site !
http://reflex.gforge.inria.fr
http://disc.inria.fr/perso/philippe.poulard/xml/active-tags/
You'll find on the RefleX web site some tutorials that are showing the
traditional "hello world" example, how to publish an entire XML
repository to HTML, how to map SQL to XML, how to design an MVC
architecture, and how to play with datatypes and PSVI ; most of them are
available in batch mode as well as in a Web application ready to run.
Don't say anymore that Santa Claus doesn't exists !
Enjoy !
--
Cordialement,
///
(. .)
-----ooO--(_)--Ooo-----
| Philippe Poulard |
-----------------------
- 8
- Protected and package in iterfaceLew wrote in thread "Interface":
> What maxnesler forgot to show is that the implementing class declares
> the method to be 'public', which is implied automatically in the
> interface declaration
Why did the people writing the Java specs decide that an interface
should not contain protected and package methods?
I can imagine several cases where this would be useful.
Phil
- 9
- Extracting c++ header from jar file using javahI'm trying to create a native header from an existing jar file
(actually, only one class w/in the jar file). I've tried all sorts of
command line arguments (w/ classpath) and nothing seems to work.
Here's the setup:
* package is blah.jar and contains dozens of classes, one of which I'm
interested in creating a .h for (blahClass.java)
* I have the source for it in another directory but its dependencies
are pretty large and I figure using javah on the .jar file would be
easiest?
* why wouldn't this work:
javah -classpath c:\temp\work\blah.jar blahClass
blahClass is also part of a larger package (net.program.message) so I
also tried:
javah -classpath c:\temp\work\blah.jar net.program.message.blahClass
nothing works.
any ideas? thx
- 10
- Why does a method act differently when invoked manually to when invoked through the driver class?Can anyone tell me why, when I run the driver class InstantiateFerry to read
a file containing the test just below, this part of the code:
ferry.getvehicleLocation(); produces the message Vehicle MVK806R is in lane
1 and position 1, which I don't want, but when I enter the file details
manually and invoke the method public void getvehicleLocation(), I get the
message I want with correct values for lane and position rather than just 1
and 1 every time?
BLUEJ_BELLE 3 120.0 285
# Test1.txt: Demonstration file for Project 2, November 2004
KR02123 1.04 5.1
DR02123 1.56 7.64
XR02123 1.049 5.1
L02123 3.15 17.1
YR02123 1.04 5.1
FR02123 1.56 7.65
BB51765 1.125 6.75
DB51765 1.6875 10.125
MVK806R 1.6875 10.125
FR02123 2.33 11.43
BR02123 1.049 5.1
MR02123 1.5735 7.66
SR02123 1.5735 7.63
CR02123 1.5735 7.64
public void addVehicle(Vehicle v)
{
int count = 0;
//System.out.println("deckLength "+deckLength+ " takenSpace
"+takenSpace+" getspaceTaken "+v.getspaceTaken());
if(deckLength < (takenSpace + v.getspaceTaken()))
{
laneCount += 1;
spaceLeft = takenSpace;
takenSpace = 0;
counter = 0;
}
//System.out.println("lanes " +lanes+ " laneCount " +laneCount);
if(laneCount == lanes)
{
System.out.println("Vehicle " + v.getReg() + " cannot board the
ferry as it is full.");
return;
}
while (deckArray[laneCount][count]!= null)
{
count += 1;
}
deckArray[laneCount][count] = v;
vehicleCount += 1;
for(int i = counter ; i < deckLength-1; i++)
{
if(deckArray[laneCount][i]!=null)
{
Vehicle vehicle = deckArray[laneCount][i];
takenSpace += vehicle.getspaceTaken();
}
}
counter += 1;
}
public void getvehicleLocation()
{
for(int lanePos = 0; lanePos < deckLength-1; lanePos++)
for(int laneLocation = 0; laneLocation < lanes; laneLocation++)
{
if(deckArray[laneLocation][lanePos]!=null)
{
Vehicle vehicle2 = deckArray[laneLocation][lanePos];
if (vehicle2.getReg() == "MVK806R")
{
vLane = laneLocation;
vPos = lanePos;
}
}
}
System.out.println("Vehicle MVK806R is in lane " + (vLane + 1) + "
and position " + (vPos + 1));
}
public int getlanePos()
{
return (vPos + 1);
}
public int getlaneLocation()
{
return (vLane + 1);
}
}
public class InstantiateFerry
{
private InstantiateFerry()
{
// Instances of this class are never created.
}
public static void main(String[] args)
{
// Here is an example statement showing you how to get at the name of
the
try
{
FileReader inFile = new FileReader(args[0]); // Open
the file
BufferedReader buffReader = new BufferedReader(inFile); // Turn
into BufferedReader
boolean endOfFile = false;
double totalCost = 0;
String line;
line = buffReader.readLine();
StringTokenizer st = new StringTokenizer(line);
st = new StringTokenizer(line, "\t");
String token = st.nextToken();
String token2 = st.nextToken();
int fLanes = Integer.parseInt(token2);
String token3 = st.nextToken();
double fLength = Double.parseDouble(token3);
String token4 = st.nextToken();
int fMiles = Integer.parseInt(token4);
Ferry ferry = new Ferry(token, fLanes, fLength, fMiles);
String line2;
line2 = buffReader.readLine();
System.out.println(line2);
double ferryLength = ferry.getLength();
//System.out.println(ferryLength);
do
{
String line3;
line3 = buffReader.readLine();
StringTokenizer st2 = new StringTokenizer(line3);
if (line3.equals(""))
{
endOfFile = true;
break;
}
else
{
while(st2.hasMoreTokens())
{ if (line3.equals(""))
{
endOfFile = true;
break;
}
else
{
String token5 = st2.nextToken();
String token6 = st2.nextToken();
double vWeight = Double.parseDouble(token6);
String token7 = st2.nextToken();
double vLength = Double.parseDouble(token7);
Vehicle vehicle = new Vehicle(token5, vWeight, vLength);
ferry.addVehicle(vehicle);
Money money = ferry.cost(vehicle);
totalCost += money.getCost();
//System.out.println(ferry.getSpace());
}
}
}
}
while (!endOfFile);
buffReader.close();
System.out.println(ferry.getferryName());
System.out.println("There are " + ferry.getVehicles() + " on the
ferry.");
System.out.println("There is " + ferry.getspaceLeft() + " metres
of space left on the ferry.");
System.out.println(totalCost);
ferry.getvehicleLocation();
// This method is supposed to find the location of Vehicle
"MVK806R".
}
catch (IOException e)
{
System.out.println("Caught unexpected exception " +
e.toString());
return;
}
} // End readFileBufferedReader()
} // End main()
- 11
- Simple recursion / stack question
Hi All,
I suspect this is a bit of a 'how long is a piece of string' type question
(the answer to which is of course precisely 2 x half its length) but I'm
going to ask it anyway.....
How deep is the java process stack? If I write some complicated piece of
code that is recursive, how can I know if I will run out of stack doing the
recursion or not?
Michael
- 12
- Bug#166370: Join our marketing teamWe are Looking for partners worldwide. The position is home-based. Our Company Head Office is located in UK with branches all over the world. We are looking for talented, honest, reliable representatives from different regions. The ideal candidate will be an intelligent person, someone who can work autonomously with a high degree of enthusiasm. Our Company offers a very competitive salary to the successful candidate, along with an unrivalled career progression opportunity.
If you would like to work with our active, dynamic team, we invite you to apply for employment. Preference will be given to applicants with knowledge of multiple languages.
Please send the following information to email***@***.com.
1. Full name
2 Address of residence
3 Contact Phone numbers
4 Languages spoken
5 Whether you are interested in part time job or full time employment.
Thank you. We look forward to working with you.
If you received this message in error, please send a blank email to: email***@***.com.
--
To UNSUBSCRIBE, email to email***@***.com
with a subject of "unsubscribe". Trouble? Contact email***@***.com
- 13
- JDialog dispose and application window poppingHello!
I have an application where I show a JDialog (sort of as a status
indicator). During this time, I launch an application like Excel
(which comes up successfully). Once that other application is
launched, I take down my dialog by calling dlg.dispose(). Note that
the user did NOT interact with that dialog.
After the dialog disappears, my application pops itself to be
frontmost. I cannot figure out how to make my application stop this
behavior. I want the second application (Excel in this case), to
remain in front.
I have been searching all over and cannot find any solution to this
problem. I do know its tied up with the dispose() because not invoking
it leaves things the way I want (except that my modal dialog is still
up).
Any pointers would be appreciated.
Allan
- 14
- Saving a BufferedImage as a JPEGI am saving a BufferedImage as a JPEG file under Windows XP.
I am using the JAI JPEGImageEncoder class.
The JPEG is saved as CMYK but I need RGB.
I cannot figure out how to get RGB. Any help?
- 15
- ObjectWebCon'06 - Call For Proposals CALL FOR PROPOSALS OBJECTWEBCON06 ObjectWeb Annual Conference 5th EDITION Paris France Januar 31st Februar 2nd 2006 http: ObjectWebCon06 object eb org SUBMISSION DEADLINE: No ember 21th 2005 ObjectWebCon06 the ne t ObjectWeb annual conference ill take place in Paris la D fense France from Januar 31st to Februar 2nd 2006 As ObjectWeb is mo ing in Anal st reports from a pure technical pla er in open source infrastructure soft are to a consortium of market pla ers its annual conferences strengthens as unique opportunit for professionals to disco er learn and e change on middle are and open source soft are technolog and Ecos stems As an e perienced professional of the domain ou are in ited to submit proposals in one or more of the follo ing sessions: Parallel sessions Best use case a ards Podium talks Please freel distribute this call to interested colleagues and friends We thank ou for making our submission online before No ember 21th and are looking for ard to reading our proposals Best regards Object ebCon06 Program Committee mailto:OWCon06 contact@object eb org Note: More information can be found on the eb at http: ObjectWebCon06 object eb org or belo in plain te t form ============================================================================ The ObjectWebCon06 program committee is seeking to recei ing proposals for the follo ing sessions: 1 Parallel sessions 45 minutes ================================== Sessions ill co er the three follo ing topics: T1 Using Open Source Middle are for : 3 presentations in each topic enterprise Ja a APS J2EE Webportal B2B BI SOA application integration ESB Clustering GRID autonomic management pro isioning large scale s stems Ad hoc net orked s stems telco mobilit RFID embedded T2 In the business of Open Source Middle are 6 presentations Business models legal aspects OSS Strateg public policies real orld cases go ernmental uses T3 Focus on ObjectWeb projects 10 presentations O er ie introduction primers guided tours getting started ith ObjectWeb projects Guideline to submit in Parallel sessions The title of the presentation A brief outline or abstract of the presentation not to e ceed 400 ords For each speaker the speaker name title compan professional street and email addresses phone and fa numbers Addresses phone and fa numbers are for organi ation purposes onl and ill not be distributed to third parties ithout prior agreement A short biograph of the proposed speaker s sho ing rele ant e perience and qualification to speak on the proposed subject matter not to e ceed 300 ords Submissions should be made online at http: ObjectWebCon06 object eb org iki bin ie Main CFP and should be ritten in English presentations are to be gi en in English Important dates for Parallel sessions: Abstract due: No ember 21th 2005 Notification: starting December 5th 2005 2 Best Use Cases A ards ======================== The ObjectWebCon06 Best Use Cases contest is a challenge for hich ou ma file one or se eral submissions about real orld use cases of ObjectWeb components and platforms Winners ill be nominated b ObjectWeb members through on line ote December 1st 15th A ards ill be offered in the follo ing categories: A1: Entreprise Ja a: production use of ObjectWeb enterprise Ja a components and platforms A2: ISV Integration: commercial offering or de elopment embedding some ObjectWeb components A3: Jur s Special Pri e: an use of ObjectWeb components and platforms Guideline to run for Use Cases A ards: A brief outline or abstract not to e ceed 150 ords ObjectWeb components that ha e been used a comment about this success h has it been a success according to ou? In option ou ma add: a complete description of the Use Case screenshots Submission should be made online at http: ObjectWebCon06 object eb org iki bin ie Main A ardsForm Important dates for Use Case A ards: Abstract due: No ember 21st 2005 Online ote: December 1 12 Notification: Starting December 15th 3 Podium talks =============== Podium talks intends to gi e all participants an opportunit to present ork the do relating to open source middle are Podium speaker ill ha e the floor for 10 minutes and ma use up to 5 slides Podium talks ill complement technical sessions on the follo ing topics: enterprise grid J2EE APS SOA ESB Telco Guideline for podium speakers: Podium talks are scheduled on a first come first ser ed basis Send an email to OWCon06 contact@object eb org in order to reser e a slot On behalf of the ObjectWebCon 06 Organi ation Committee Xa ier MOGHRABI ObjectWeb Consortium http: object eb org
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