content: /*
   * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.nio.channels;
  
  import java.io.IOException;
  import java.io.Closeable;
  
  
  /**
   * A nexus for I/O operations.
   *
   * <p> A channel represents an open connection to an entity such as a hardware
   * device, a file, a network socket, or a program component that is capable of
   * performing one or more distinct I/O operations, for example reading or
   * writing.
   *
   * <p> A channel is either open or closed.  A channel is open upon creation,
   * and once closed it remains closed.  Once a channel is closed, any attempt to
   * invoke an I/O operation upon it will cause a {@link ClosedChannelException}
   * to be thrown.  Whether or not a channel is open may be tested by invoking
   * its {@link #isOpen isOpen} method.
   *
   * <p> Channels are, in general, intended to be safe for multithreaded access
   * as described in the specifications of the interfaces and classes that extend
   * and implement this interface.
   *
   *
   * @author Mark Reinhold
   * @author JSR-51 Expert Group
   * @since 1.4
   */
  
  public interface Channel extends Closeable {
  
      /**
       * Tells whether or not this channel is open.
       *
       * @return <tt>true</tt> if, and only if, this channel is open
       */
      public boolean isOpen();
  
      /**
       * Closes this channel.
       *
       * <p> After a channel is closed, any further attempt to invoke I/O
       * operations upon it will cause a {@link ClosedChannelException} to be
       * thrown.
       *
       * <p> If this channel is already closed then invoking this method has no
       * effect.
       *
       * <p> This method may be invoked at any time.  If some other thread has
       * already invoked it, however, then another invocation will block until
       * the first invocation is complete, after which it will return without
       * effect. </p>
       *
       * @throws  IOException  If an I/O error occurs
       */
      public void close() throws IOException;
  
  }
  