SelectableChannel.java

/* SelectableChannel.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)
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02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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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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package java.nio.channels;

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


/**
 * @author Michael Koch
 * @since 1.4
 */
public abstract class SelectableChannel extends AbstractInterruptibleChannel
{
  /**
   * Initializes the channel.
   */
  protected SelectableChannel()
  {
  }
 
  /**
   * Returns the lock of this channel.
   */
  public abstract Object blockingLock();

  /**
   * Adjusts this channel's blocking mode.
   * 
   * @exception ClosedChannelException If this channel is closed.
   * @exception IllegalBlockingModeException If block is true and this channel
   * is registered with one or more selectors.
   * @exception IOException If an error occurs.
   */
  public abstract SelectableChannel configureBlocking(boolean block)
    throws IOException;
  
  /**
   * Tells whether this channel is blocking or not.
   */
  public abstract boolean isBlocking();
  
  /**
   * Tells whether or not this channel is currently registered with
   * any selectors.
   */
  public abstract boolean isRegistered();
  
  /**
   * Retrieves the key representing the channel's registration with
   * the given selector.
   */
  public abstract SelectionKey keyFor(Selector sel);
  
  /**
   * Returns the provider that created this channel.
   */
  public abstract SelectorProvider provider();
  
  /**
   * Registers this channel with the given selector,
   * returning a selection key.
   * 
   * @exception CancelledKeyException If this channel is currently registered
   * with the given selector but the corresponding key has already been cancelled
   * @exception ClosedChannelException If this channel is closed.
   * @exception IllegalArgumentException If a bit in ops does not correspond
   * to an operation that is supported by this channel, that is, if
   * set & ~validOps() != 0.
   * @exception IllegalBlockingModeException If block is true and this channel
   * is registered with one or more selectors.
   * @exception IllegalSelectorException If this channel was not created by
   * the same provider as the given selector.
   */
  public final SelectionKey register(Selector sel, int ops)
    throws ClosedChannelException
  {
    return register(sel, ops, null);
  }
  
  /**
   * Registers this channel with the given selector,
   * returning a selection key.
   *
   * @exception CancelledKeyException If this channel is currently registered
   * with the given selector but the corresponding key has already been
   * cancelled.
   * @exception ClosedChannelException If this channel is closed.
   * @exception IllegalArgumentException If a bit in ops does not correspond
   * to an operation that is supported by this channel, that is, if
   * set & ~validOps() != 0.
   * @exception IllegalBlockingModeException If block is true and this channel
   * is registered with one or more selectors.
   * @exception IllegalSelectorException If this channel was not created by
   * the same provider as the given selector.
   */
  public abstract SelectionKey register(Selector sel, int ops, Object att)
    throws ClosedChannelException;
  
  /**
   * Returns a set of valid operations on this channel.
   */
  public abstract int validOps();
}