Commons Net example source code file (ListNewsgroups.java)

This example Commons Net source code file (ListNewsgroups.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Net tags/keywords

io, ioexception, ioexception, listnewsgroups, listnewsgroups, nntpclient, nntpclient, string, string

The Commons Net ListNewsgroups.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package examples.nntp;

import java.io.IOException;
import org.apache.commons.net.nntp.NNTPClient;
import org.apache.commons.net.nntp.NewsgroupInfo;

/***
 * This is a trivial example using the NNTP package to approximate the
 * Unix newsgroups command.  It merely connects to the specified news
 * server and issues fetches the list of newsgroups stored by the server.
 * On servers that store a lot of newsgroups, this command can take a very
 * long time (listing upwards of 30,000 groups).
 * <p>
 ***/

public final class ListNewsgroups
{

    public final static void main(String[] args)
    {
        if (args.length < 1)
        {
            System.err.println("Usage: newsgroups newsserver [pattern]");
            return;
        }

        NNTPClient client = new NNTPClient();
        String pattern = args.length >= 2 ? args[1] : "";

        try
        {
            client.connect(args[0]);

            int j = 0;
            try {
                for(String s : client.iterateNewsgroupListing(pattern)) {
                    j++;
                    System.out.println(s);
                }
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            System.out.println(j);

            j = 0;
            for(NewsgroupInfo n : client.iterateNewsgroups(pattern)) {
                j++;
                System.out.println(n.getNewsgroup());
            }
            System.out.println(j);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        finally
        {
            try
            {
                if (client.isConnected())
                    client.disconnect();
            }
            catch (IOException e)
            {
                System.err.println("Error disconnecting from server.");
                e.printStackTrace();
                System.exit(1);
            }
        }

    }

}