Re: OT:News readers..so many to choose from
On Jan 26, 9:36 pm, "Daniel Pitts" <googlegrou...@coloraura.com> wrote:
On Jan 26, 6:47 pm, Print Dude <printerdude1...@gmail.com> wrote:
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.
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>