/* DatagramChannel.java -- 
   Copyright (C) 2002 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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, or (at your option)
any later version.

GNU Classpath 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 GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package java.nio.channels;

import java.io.IOException;
import java.net.DatagramSocket;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.spi.AbstractSelectableChannel;
import java.nio.channels.spi.SelectorProvider;

/**
 * @since 1.4
 */
public abstract class DatagramChannel
  extends AbstractSelectableChannel
  implements ByteChannel, ScatteringByteChannel, GatheringByteChannel
{
  /**
   * Initializes the channel.
   */
  protected DatagramChannel (SelectorProvider provider)
  {
    super (provider);
  }

  /**
   * Opens a datagram channel.
   *
   * @exception IOException If an error occurs
   */
  public static DatagramChannel open () throws IOException
  {
    return SelectorProvider.provider ().openDatagramChannel ();
  }
  
  /**
   * Reads data from this channel.
   */
  public final long read (ByteBuffer[] dsts) throws IOException
  {
    long b = 0;
    
    for (int i = 0; i < dsts.length; i++)
      b += read (dsts[i]);
    
    return b;
  }
  
  /**
   * Writes data to this channel.
   *
   * @exception IOException If an error occurs
   * @exception NotYetConnectedException The channel's socket is not connected.
   */
  public final long write (ByteBuffer[] srcs) throws IOException
  {
    long b = 0;
    
    for (int i = 0;i < srcs.length; i++)
      b += write (srcs[i]);
    
    return b;
  }
    
  /**
   * Connects this channel's socket.
   *
   * @exception AsynchronousCloseException If another thread closes this channel
   * while the connect operation is in progress.
   * @exception ClosedByInterruptException If another thread interrupts the
   * current thread while the read operation is in progress, thereby closing the
   * channel and setting the current thread's interrupt status.
   * @exception ClosedChannelException If this channel is closed.
   * @exception IOException If an error occurs.
   * @exception SecurityException If a security manager has been installed and
   * it does not permit datagrams to be sent to the given address.
   */
  public abstract DatagramChannel connect (SocketAddress remote)
    throws IOException;

  /**
   * Disonnects this channel's socket.
   *
   * @exception IOException If an error occurs
   */
  public abstract DatagramChannel disconnect () throws IOException;

  /**
   * Tells whether or not this channel's socket is connected.
   *
   * @exception IOException If an error occurs.
   * @exception NotYetConnectedException The channel's socket is not connected.
   */
  public abstract boolean isConnected ();
  
  /**
   * Reads data from this channel.
   */
  public abstract int read (ByteBuffer dst) throws IOException;
  
  /**
   * Reads data from this channel.
   *
   * @exception IOException If an error occurs.
   * @exception NotYetConnectedException The channel's socket is not connected.
   */
  public abstract long read (ByteBuffer[] dsts, int offset, int length)
    throws IOException;
 
  /**
   * Receives a datagram via this channel.
   *
   * @exception AsynchronousCloseException If another thread closes this channel
   * while the connect operation is in progress.
   * @exception ClosedByInterruptException If another thread interrupts the
   * current thread while the read operation is in progress, thereby closing the
   * channel and setting the current thread's interrupt status.
   * @exception ClosedChannelException If this channel is closed.
   * @exception IOException If an error occurs
   * @exception SecurityException If a security manager has been installed and
   * it does not permit datagrams to be sent to the given address.
   */
  public abstract SocketAddress receive (ByteBuffer dst) throws IOException;
 
  /**
   * Sends a datagram via this channel.
   *
   * @exception AsynchronousCloseException If another thread closes this channel
   * while the connect operation is in progress.
   * @exception ClosedByInterruptException If another thread interrupts the
   * current thread while the read operation is in progress, thereby closing the
   * channel and setting the current thread's interrupt status.
   * @exception ClosedChannelException If this channel is closed.
   * @exception IOException If an error occurs
   * @exception SecurityException If a security manager has been installed and
   * it does not permit datagrams to be sent to the given address.
   */
  public abstract int send (ByteBuffer src, SocketAddress target)
    throws IOException;
 
  /**
   * Retrieves the channel's socket.
   */
  public abstract DatagramSocket socket ();
  
  /**
   * Writes data to this channel.
   *
   * @exception IOException If an error occurs.
   * @exception NotYetConnectedException The channel's socket is not connected.
   */
  public abstract int write (ByteBuffer src) throws IOException;
  
  /**
   * Writes data to this channel.
   *
   * @exception IOException If an error occurs.
   * @exception NotYetConnectedException The channel's socket is not connected.
   */
  public abstract long write (ByteBuffer[] srcs, int offset, int length)
    throws IOException;

  /**
   * Retrieves the valid operations for this channel.
   *
   * @exception IOException If an error occurs.
   * @exception NotYetConnectedException The channel's socket is not connected.
   */
  public final int validOps ()
  {
    return SelectionKey.OP_READ | SelectionKey.OP_WRITE;
  }    
}
