/* Pipe.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
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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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
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independent module, the terms and conditions of the license of that
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package java.nio.channels;

import java.io.IOException;
import java.nio.channels.spi.AbstractSelectableChannel;
import java.nio.channels.spi.SelectorProvider;

/**
 * @author Michael Koch
 * @since 1.4
 */
public abstract class Pipe
{
  public abstract static class SinkChannel
    extends AbstractSelectableChannel
    implements WritableByteChannel, GatheringByteChannel
  {
    /**
     * Initializes the channel.
     */
    protected SinkChannel (SelectorProvider provider)
    {
      super (provider);
    }

    /**
     * Returns an operation set that is valid on this channel.
     *
     * The only valid operation on this channel is @see SelectionKey.OP_WRITE.
     */
    public final int validOps ()
    {
      return SelectionKey.OP_WRITE;
    }
  }

  public abstract static class SourceChannel
    extends AbstractSelectableChannel
    implements ReadableByteChannel, ScatteringByteChannel
  {
    /**
     * Initializes the channel.
     */
    protected SourceChannel (SelectorProvider provider)
    {
      super (provider);
    }

    /**
     * Returns an operation set that is valid on this channel.
     *
     * The only valid operation on this channel is @see SelectionKey.OP_READ.
     */
    public final int validOps ()
    {
      return SelectionKey.OP_READ;
    }
  }

  /**
   * Initializes the pipe.
   */
  protected Pipe()
  {
  }

  /**
   * Opens a pipe.
   * 
   * @exception IOException If an error occurs
   */
  public static Pipe open() throws IOException
  {
    return SelectorProvider.provider ().openPipe();
  }

  /**
   * Returns a pipe's sink channel.
   */
  public abstract Pipe.SinkChannel sink();

  /**
   * Returns a pipe's source channel
   */
  public abstract Pipe.SourceChannel source();   
}