OT:News readers..so many to choose from

[Print Dude]

Well I've abandoned google groups for the time being and have switched
over to PAN on Linux and Gravity on Windows. What I am wondering is,
how hard would it be to write a news reader client in Java? I know it's
way beyond me, but there must be people reading this ng who have had
some degree of sucess at it. What was the process you went through to
design and build the program? How much practical experience would one
need to be able to sucessfully code such a program? If you know that
you need say, a class that will send a request to a news server, how do
you go about finding it in the API documentation? And if you don't find
one, do you write your own or simply extend one that is already there,
and is close to what you need? I have a book on OO Design coming, but
it would be interesting to know what others think. I know this is
pseudo-off topic, which is why I put the OT in the subject line. This
is my first post using Gravity so it may not work, but if it does, I
hope we can have a good discussion about this topic, if it hasn't
already been hash(tabled) before.

Cheers

 

[Daniel Pitts]

Well I've abandoned google groups for the time being and have switched
over to PAN on Linux and Gravity on Windows. What I am wondering is,
how hard would it be to write a news reader client in Java? I know it's
way beyond me, but there must be people reading this ng who have had
some degree of sucess at it. What was the process you went through to
design and build the program? How much practical experience would one
need to be able to sucessfully code such a program? If you know that
you need say, a class that will send a request to a news server, how do
you go about finding it in the API documentation? And if you don't find
one, do you write your own or simply extend one that is already there,
and is close to what you need? I have a book on OO Design coming, but
it would be interesting to know what others think. I know this is
pseudo-off topic, which is why I put the OT in the subject line. This
is my first post using Gravity so it may not work, but if it does, I
hope we can have a good discussion about this topic, if it hasn't
already been hash(tabled) before.

Cheers

Actually, writing a simple newsreader probably wouldn't be too hard,
the NNTP protocol is well documented, and socket programming is "too
easy" in Java.

Out of curiousity, did you abandon Google because of their new look and
feel?
I don't like it myself, but I haven't bothered finding an alternative
yet.

 

[Andrew Thompson]

....
Out of curiousity, did you abandon Google because of their new look and
feel?
I don't like it myself, but I haven't bothered finding an alternative
yet.- Hide quoted text -- Show quoted text -

It is pissing me off how it ..
1) reformats text.
A good e.g. is the addition of
'- Hide quoted text -- Show quoted text -'
above. I would usually trim/reformat it.
2) Does not allow me to change thread titles
(though arguably, that is a good thing, in general)
3) Will not 'auto-text'/'bring up' past x-posts I
have made, when typing in the 'Newsgroups'
box (instead it sems to produce email
addresses from my gmail account!)

...anyway, back to the ..already off-topic
thread.

Andrew T.

 

[Daniel Pitts]

Actually, writing a simple newsreader probably wouldn't be too hard,
the NNTP protocol is well documented, and socket programming is "too
easy" in Java.

To follow up. in the last 30 minuts, I wrote a simple Swing application
that will download a list of newsgroups from my local provider, and
display them in a JTree.

It wouldn't be hard to "extend" this to download messages for a
particular group.
My only references were: <http://tools.ietf.org/html/rfc977> and of
course the JDK javadoc.

Less than 100 lines of code too:
<sscce file="GroupSSCCE.java" javac="GroupSSCCE.java" run="java
GroupSSCCE">
import javax.swing.*;
import javax.swing.tree.DefaultTreeModel;
import java.awt.*;
import java.io.*;
import java.util.*;

class GroupSSCCE {
static final String MESSAGE = "Please enter your nntp server
address";

public static void main(String[] args) throws Throwable {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
JFrame.setDefaultLookAndFeelDecorated(true);
JDialog.setDefaultLookAndFeelDecorated(true);
String host = getHost();

final GroupNode root = new GroupNode(host);

final DefaultTreeModel model = new DefaultTreeModel(root);
final JLabel countLabel = new JLabel("");
initMainFrame(model, countLabel, host);

java.net.Socket socket = new java.net.Socket(host, 119);

BufferedReader in = getIn(socket);
PrintWriter out = getOut(socket);

System.out.println(in.readLine());
out.println("list");
out.flush();
System.out.println(in.readLine());

long count = 0;
for (String line = in.readLine();
line.trim().length() > 1;
line = in.readLine()) {
addGroup(root,new StringTokenizer(getGroupName(line),
"."),model);
countLabel.setText("Groups: " + ++count);
}
System.out.println("Done!");
}

static void addGroup(GroupNode node,
StringTokenizer tokenizer, DefaultTreeModel model)
{
while (tokenizer.hasMoreTokens()) {
node = node.walkTo(model, tokenizer.nextToken());
}
}

static String getHost() {
return JOptionPane.showInputDialog(MESSAGE, "news.astound.net");
}

static PrintWriter getOut(java.net.Socket socket) throws Throwable {
return new PrintWriter(socket.getOutputStream());
}

static BufferedReader getIn(java.net.Socket socket) throws Throwable
{
return new BufferedReader(
new InputStreamReader(socket.getInputStream()));
}

static void initMainFrame(final DefaultTreeModel model,
final JLabel countLabel, final String
host){
SwingUtilities.invokeLater(new Runnable() {
public void run() {
final JFrame jframe = new JFrame("Groups: " + host);
jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jframe.getContentPane().add(new JScrollPane(new JTree(model)),
BorderLayout.CENTER);
jframe.getContentPane().add(countLabel, BorderLayout.SOUTH);
jframe.setLocationRelativeTo(null);
jframe.pack();
jframe.setVisible(true);
}
});
}

static String getGroupName(String line) {
return new StringTokenizer(line).nextToken();
}
}

class GroupNode extends javax.swing.tree.DefaultMutableTreeNode {
HashMap<String, GroupNode> kids = new HashMap<String, GroupNode>();
GroupNode(String name) {
super(name, true);
}
GroupNode walkTo(DefaultTreeModel model, String child) {
GroupNode node = kids.get(child);
if (node == null) {
node = new GroupNode(child);
kids.put(child, node);
add(node);
model.nodesWereInserted(this, new int[] {children.size()-1});
}
return node;
}
}
</sscce>

 

[Print Dude]

Out of curiousity, did you abandon Google because of their new look and
feel?
I don't like it myself, but I haven't bothered finding an alternative
yet.

Pretty much my reasoning. I'm not sure I like Gravity all that much
either. PAN on Linux is great so far.

As I expected, the code you show later is way beyond me but it looks
like someone with a fair amount of experience with Swing and networking
and sockets could do it. I've got a long way to go...

 

[Print Dude]

..anyway, back to the ..already off-topic
thread.

.....which you never did respond to I know it's off topic, which is
why I added OT to the subject line (isn't this the correct way to start
a discussion which may be considered off-topic). Do you have anything
that you can add to the discussion about newsreader client construction,
in particular the process you would go through to come up with such a
product?

 

[Andrew Thompson]

which you never did respond to I know it's off topic, which is
why I added OT to the subject line (isn't this the correct way to start
a discussion which may be considered off-topic).

(shrugs) Yeah.. hey I was just going with your
flow*, usually I do not even bother to mention
when /I/ begin to take a conversation OT.

(* Not that I regard discussions on posting
tools to be off-topic for any NG.)

.. Do you have anything
that you can add to the discussion about newsreader client construction,
in particular the process you would go through to come up with such a
product?

No. It is not my particular area of specialty, and
it looks like Daniel has already posted code that
would get you further than my sum total of
knowledge of writing a news client.

Andrew T.

 

[Lew]

I am partial to Mozilla Thunderbird.

BTW, how is writing a newsgroup reader in Java OT for this group? Seems pretty
on topic to me, but, hey.

- Lew

 

[Print Dude]

Hi, I copied and pasted your code into Eclipse but it won't run.
Here's the error dump I get:

java.lang.UnsupportedClassVersionError: Bad version number in .class
file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
at java.security.SecureClassLoader.defineClass
(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
Exception in thread "main"

Any ideas? I've set the jdk to 1.6 and rebuilt the project a couple of
times, to no avail.

 

[Print Dude]

I am partial to Mozilla Thunderbird.

BTW, how is writing a newsgroup reader in Java OT for this group? Seems pretty
on topic to me, but, hey.

- Lew

Not sure. The idea of OO Design (the process, not the end result) may
be considered Off-Topic by some. The FAQ (which I have read extensivly)
talks about what is considered verboten and not, but it seemed to me as
I was trying to formulate my question, that this would be the best forum
to post in. It's not exactly a plea for help, so c.l.j.h would not
work, neither would c.l.j.g And since these are the only 3 forums I
subscribe to, the process of elimination left c.l.j.p

 

[Print Dude]

No. It is not my particular area of specialty, and

it looks like Daniel has already posted code that
would get you further than my sum total of
knowledge of writing a news client.

Andrew T.

Fair enough. But I am more interested in the process of OOD. I only
used a newsreader as my example because it seemed to be a practical
application of the methodology. Things have changed in the IT world
since the days of the Yourdon Structured Design Course which I took back
in 1990. I have a couple of books on design patterns, including
HeadFirst, Design Patterns in Java and .... tada .... Essential Java (a
book which I purchased at the recommendation of my instructor when I
took a course in Java a couple of years ago).

 

[Print Dude]

To follow up. in the last 30 minuts, I wrote a simple Swing application
that will download a list of newsgroups from my local provider, and
display them in a JTree.

Not sure why Eclipse had a problem with this, but running it from the
command line with javac and java works perfectly.

 

[Alex Hunsley]

Well I've abandoned google groups for the time being and have switched
over to PAN on Linux and Gravity on Windows. What I am wondering is,
how hard would it be to write a news reader client in Java?

Not too hard, if you're comfortable with development up to a certain
level. I've often thought of features I wish would appear in
newsreaders/posters....

I know it's
way beyond me, but there must be people reading this ng who have had
some degree of sucess at it. What was the process you went through to
design and build the program? How much practical experience would one
need to be able to sucessfully code such a program? If you know that
you need say, a class that will send a request to a news server, how do
you go about finding it in the API documentation? And if you don't find
one, do you write your own or simply extend one that is already there,
and is close to what you need? I have a book on OO Design coming, but
it would be interesting to know what others think. I know this is
pseudo-off topic, which is why I put the OT in the subject line. This
is my first post using Gravity so it may not work, but if it does, I
hope we can have a good discussion about this topic, if it hasn't
already been hash(tabled) before.

One of the important concerns is finding out about the core technology -
news works via the NNTP protocol - and what is available to help you
(e.g. APIs). When I googled for "java nntp api", I found a pointer to
JavaMail:

http://java.sun.com/developer/onlineTraining/JavaMail/contents.html

From this page I found the following 3rd party JavaMail 'providers':

http://java.sun.com/products/javamail/Third_Party.html

...from which I found a link to this:
http://www.dog.net.uk/knife/

... and via the link to classpathx project I found, finally:

http://www.gnu.org/software/classpathx/javamail/javamail.html

This last page tells you about GNU JavaMail providers - they have an
NNTP provider, which is an API you can use to read/post newsgroup
messages...

lex

 

[Chris Smith]

Not sure why Eclipse had a problem with this, but running it from the
command line with javac and java works perfectly.

Sounds like a configuration problem; for example, perhaps you've got
Eclipse running with a 1.5 JRE, but thinking it's a 1.6 JRE.

 

[Chris Smith]

Not sure. The idea of OO Design (the process, not the end result) may
be considered Off-Topic by some.

This group is pretty laid back compared to many others. You're
generally welcome to discuss a lot of things here, so long as they are
relevant to Java programming. You might start getting some complaints
if you wanted to discuss OO design and post all your examples in
Smalltalk; but design in general is fine.

That's a commnunity norm. If you go over to comp.lang.c, you'll find a
completely different set of rules (namely, that almost any imaginable
question is considered off-topic there).