/*
 * $Id: LineIterator.java,v 1.3 2004/06/09 18:24:40 dog Exp $
 * Copyright (C) 2002 The Free Software Foundation
 * 
 * This file is part of GNU inetlib, a library.
 * 
 * GNU inetlib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU inetlib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * As a special exception, if you link this library with other files to
 * produce an executable, this library does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * This exception does not however invalidate any other reasons why the
 * executable file might be covered by the GNU General Public License.
 */

package gnu.inet.nntp;

import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * An iterator over an NNTP multi-line response.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 * @version $Revision: 1.3 $ $Date: 2004/06/09 18:24:40 $
 */
public class LineIterator implements Iterator, PendingData
{

  static final String DOT = ".";

  boolean doneRead = false;
  NNTPConnection connection;
  String current;

  LineIterator (NNTPConnection connection)
    {
      this.connection = connection;
    }

  void doRead () throws IOException
    {
      if (doneRead)
        {
          return;
        }
      String line = connection.read ();
      if (DOT.equals (line))
        {
          current = null;
        }
      else
        {
          current = line;
        }
      doneRead = true;
    }

  /**
   * Indicates whether there are more lines to be read.
   */
  public boolean hasNext ()
    {
      try
        {
          doRead ();
        }
      catch (IOException e)
        {
          return false;
        }
      return (current != null);
    }

  /**
   * Returns the next line.
   */
  public Object next ()
    {
      try
        {
          return nextLine ();
        }
      catch (IOException e)
        {
          throw new NoSuchElementException ("I/O error: " + e.getMessage ());
        }
    }

  /**
   * Returns the next line.
   */
  public String nextLine () throws IOException
    {
      doRead ();
      if (current == null)
        {
          throw new NoSuchElementException ();
        }
      doneRead = false;
      return current;
    }

  /**
   * This iterator is read-only.
   */
  public void remove ()
    {
      throw new UnsupportedOperationException ();
    }

  /**
   * Read to the end of this iterator.
   */
  public void readToEOF () throws IOException
    {
      do
        {
          doRead ();
        }
      while (current != null);
    }

}
