org/sonews/storage/Article.java
author cli
Wed, 12 Aug 2009 13:03:23 +0200
changeset 7 0b76e099eb96
parent 3 2fdc9cc89502
child 12 bb6990c0dd1a
permissions -rw-r--r--
PullFeeder sends an addition "MODE READER" to peers.
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/*
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 *   SONEWS News Server
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 *   see AUTHORS for the list of contributors
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 *
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 *   This program is free software: you can redistribute it and/or modify
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 *   it under the terms of the GNU General Public License as published by
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 *   the Free Software Foundation, either version 3 of the License, or
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 *   (at your option) any later version.
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 *
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 *   This program is distributed in the hope that it will be useful,
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 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *   GNU General Public License for more details.
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 *
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 *   You should have received a copy of the GNU General Public License
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 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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package org.sonews.storage;
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import java.io.ByteArrayInputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.charset.Charset;
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import java.security.MessageDigest;
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import java.security.NoSuchAlgorithmException;
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import java.util.UUID;
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import java.util.ArrayList;
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import java.util.Enumeration;
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import java.util.List;
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import javax.mail.Header;
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import javax.mail.Message;
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import javax.mail.MessagingException;
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import javax.mail.Multipart;
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import javax.mail.internet.InternetHeaders;
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import org.sonews.config.Config;
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import org.sonews.util.Log;
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/**
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 * Represents a newsgroup article.
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 * @author Christian Lins
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 * @author Denis Schwerdel
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 * @since n3tpd/0.1
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 */
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public class Article extends ArticleHead
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{
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  /**
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   * Loads the Article identified by the given ID from the JDBCDatabase.
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   * @param messageID
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   * @return null if Article is not found or if an error occurred.
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   */
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  public static Article getByMessageID(final String messageID)
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  {
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    try
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    {
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      return StorageManager.current().getArticle(messageID);
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    }
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    catch(StorageBackendException ex)
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    {
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      ex.printStackTrace();
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      return null;
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    }
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  }
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  private byte[] body       = new byte[0];
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  /**
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   * Default constructor.
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   */
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  public Article()
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  {
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  }
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  /**
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   * Creates a new Article object using the date from the given
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   * raw data.
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   */
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  public Article(String headers, byte[] body)
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  {
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    try
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    {
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      this.body  = body;
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      // Parse the header
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      this.headers = new InternetHeaders(
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        new ByteArrayInputStream(headers.getBytes()));
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      this.headerSrc = headers;
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    }
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    catch(MessagingException ex)
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    {
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      ex.printStackTrace();
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    }
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  }
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  /**
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   * Creates an Article instance using the data from the javax.mail.Message
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   * object.
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   * @see javax.mail.Message
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   * @param msg
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   * @throws IOException
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   * @throws MessagingException
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   */
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  public Article(final Message msg)
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    throws IOException, MessagingException
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  {
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    this.headers = new InternetHeaders();
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    for(Enumeration e = msg.getAllHeaders() ; e.hasMoreElements();) 
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    {
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      final Header header = (Header)e.nextElement();
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      this.headers.addHeader(header.getName(), header.getValue());
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    }
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    // The "content" of the message can be a String if it's a simple text/plain
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    // message, a Multipart object or an InputStream if the content is unknown.
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    final Object content = msg.getContent();
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    if(content instanceof String)
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    {
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      this.body = ((String)content).getBytes();
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    }
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    else if(content instanceof Multipart) // probably subclass MimeMultipart
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    {
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      // We're are not interested in the different parts of the MultipartMessage,
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      // so we simply read in all data which *can* be huge.
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      InputStream in = msg.getInputStream();
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      this.body = readContent(in);
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    }
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    else if(content instanceof InputStream)
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    {
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      // The message format is unknown to the Message class, but we can
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      // simply read in the whole message data.
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      this.body = readContent((InputStream)content);
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    }
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    else
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    {
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      // Unknown content is probably a malformed mail we should skip.
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      // On the other hand we produce an inconsistent mail mirror, but no
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      // mail system must transport invalid content.
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      Log.msg("Skipping message due to unknown content. Throwing exception...", true);
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      throw new MessagingException("Unknown content: " + content);
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    }
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    // Validate headers
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    validateHeaders();
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  }
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  /**
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   * Reads from the given InputString into a byte array.
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   * TODO: Move this generalized method to org.sonews.util.io.Resource.
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   * @param in
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   * @return
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   * @throws IOException
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   */
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  private byte[] readContent(InputStream in)
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    throws IOException
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  {
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    ByteArrayOutputStream out = new ByteArrayOutputStream();
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    int b = in.read();
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    while(b >= 0)
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    {
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      out.write(b);
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      b = in.read();
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    }
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    return out.toByteArray();
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  }
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  /**
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   * Removes the header identified by the given key.
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   * @param headerKey
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   */
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  public void removeHeader(final String headerKey)
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  {
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    this.headers.removeHeader(headerKey);
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    this.headerSrc = null;
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  }
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  /**
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   * Generates a message id for this article and sets it into
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   * the header object. You have to update the JDBCDatabase manually to make this
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   * change persistent.
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   * Note: a Message-ID should never be changed and only generated once.
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   */
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  private String generateMessageID()
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  {
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    String randomString;
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    MessageDigest md5;
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    try
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    {
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      md5 = MessageDigest.getInstance("MD5");
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      md5.reset();
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      md5.update(getBody());
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      md5.update(getHeader(Headers.SUBJECT)[0].getBytes());
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      md5.update(getHeader(Headers.FROM)[0].getBytes());
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      byte[] result = md5.digest();
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      StringBuffer hexString = new StringBuffer();
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      for (int i = 0; i < result.length; i++)
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      {
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        hexString.append(Integer.toHexString(0xFF & result[i]));
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      }
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      randomString = hexString.toString();
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    }
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    catch (NoSuchAlgorithmException e)
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    {
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      e.printStackTrace();
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      randomString = UUID.randomUUID().toString();
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    }
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    String msgID = "<" + randomString + "@"
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        + Config.inst().get(Config.HOSTNAME, "localhost") + ">";
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    this.headers.setHeader(Headers.MESSAGE_ID, msgID);
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    return msgID;
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  }
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  /**
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   * Returns the body string.
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   */
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  public byte[] getBody()
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  {
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    return body;
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  }
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  /**
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   * @return Charset of the body text
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   */
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  private Charset getBodyCharset()
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  {
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    // We espect something like 
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    // Content-Type: text/plain; charset=ISO-8859-15
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    String contentType = getHeader(Headers.CONTENT_TYPE)[0];
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    int idxCharsetStart = contentType.indexOf("charset=") + "charset=".length();
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    int idxCharsetEnd   = contentType.indexOf(";", idxCharsetStart);
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    String charsetName = "UTF-8";
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    if(idxCharsetStart >= 0 && idxCharsetStart < contentType.length())
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    {
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      if(idxCharsetEnd < 0)
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      {
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        charsetName = contentType.substring(idxCharsetStart);
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      }
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      else
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      {
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        charsetName = contentType.substring(idxCharsetStart, idxCharsetEnd);
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      }
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    }
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    // Sometimes there are '"' around the name
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    if(charsetName.length() > 2 &&
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      charsetName.charAt(0) == '"' && charsetName.endsWith("\""))
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    {
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      charsetName = charsetName.substring(1, charsetName.length() - 2);
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    }
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    // Create charset
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    Charset charset = Charset.forName("UTF-8"); // This MUST be supported by JVM
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    try
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    {
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      charset = Charset.forName(charsetName);
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    }
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    catch(Exception ex)
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    {
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      Log.msg(ex.getMessage(), false);
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      Log.msg("Article.getBodyCharset(): Unknown charset: " + charsetName, false);
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    }
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    return charset;
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  }
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  /**
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   * @return Numerical IDs of the newsgroups this Article belongs to.
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   */
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  public List<Group> getGroups()
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  {
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    String[]         groupnames = getHeader(Headers.NEWSGROUPS)[0].split(",");
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    ArrayList<Group> groups     = new ArrayList<Group>();
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    try
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    {
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      for(String newsgroup : groupnames)
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      {
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        newsgroup = newsgroup.trim();
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        Group group = StorageManager.current().getGroup(newsgroup);
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        if(group != null &&         // If the server does not provide the group, ignore it
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          !groups.contains(group))  // Yes, there may be duplicates
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        {
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          groups.add(group);
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        }
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      }
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    }
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    catch(StorageBackendException ex)
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    {
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      ex.printStackTrace();
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      return null;
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    }
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    return groups;
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  }
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  public void setBody(byte[] body)
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  {
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    this.body = body;
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  }
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  /**
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   * 
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   * @param groupname Name(s) of newsgroups
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   */
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  public void setGroup(String groupname)
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  {
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    this.headers.setHeader(Headers.NEWSGROUPS, groupname);
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  }
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  /**
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   * Returns the Message-ID of this Article. If the appropriate header
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   * is empty, a new Message-ID is created.
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   * @return Message-ID of this Article.
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   */
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  public String getMessageID()
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  {
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    String[] msgID = getHeader(Headers.MESSAGE_ID);
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    return msgID[0].equals("") ? generateMessageID() : msgID[0];
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  }
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  /**
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   * @return String containing the Message-ID.
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   */
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  @Override
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  public String toString()
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  {
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    return getMessageID();
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  }
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}