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package java.nio.channels;

import java.io.IOException;
import java.io.Closeable;


A nexus for I/O operations.
 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.
 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 ClosedChannelException to be thrown. Whether or not a channel is open may be tested by invoking its isOpen method. 
 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, JSR-51 Expert Group
Since:
1.4/**
 * 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.
Returns:
true if, and only if, this channel is open/**
     * Tells whether or not this channel is open.
     *
     * @return {@code true} if, and only if, this channel is open
     */
    public boolean isOpen();

    
Closes this channel.
 After a channel is closed, any further attempt to invoke I/O operations upon it will cause a ClosedChannelException to be thrown. 
 If this channel is already closed then invoking this method has no
effect.
 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. 
Throws:
IOException –  If an I/O error occurs/**
     * 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;

}