jdk/src/share/classes/java/nio/channels/AsynchronousDatagramChannel.java
changeset 2057 3acf8e5e2ca0
child 2589 af4853bc7e87
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/nio/channels/AsynchronousDatagramChannel.java	Sun Feb 15 12:25:54 2009 +0000
@@ -0,0 +1,718 @@
+/*
+ * Copyright 2007-2009 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.nio.channels;
+
+import java.nio.channels.spi.*;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.Future;
+import java.io.IOException;
+import java.net.SocketOption;
+import java.net.SocketAddress;
+import java.net.ProtocolFamily;
+import java.nio.ByteBuffer;
+
+/**
+ * An asynchronous channel for datagram-oriented sockets.
+ *
+ * <p> An asynchronous datagram channel is created by invoking one of the {@link
+ * #open open} methods defined by this class. It is not possible to create a channel
+ * for an arbitrary, pre-existing datagram socket. A newly-created asynchronous
+ * datagram channel is open but not connected. It need not be connected in order
+ * for the {@link #send send} and {@link #receive receive} methods to be used.
+ * A datagram channel may be connected, by invoking its {@link #connect connect}
+ * method, in order to avoid the overhead of the security checks that are otherwise
+ * performed as part of every send and receive operation when a security manager
+ * is set. The channel must be connected in order to use the {@link #read read}
+ * and {@link #write write} methods, since those methods do not accept or return
+ * socket addresses. Once connected, an asynchronous datagram channel remains
+ * connected until it is disconnected or closed.
+ *
+ * <p> Socket options are configured using the {@link #setOption(SocketOption,Object)
+ * setOption} method. An asynchronous datagram channel to an Internet Protocol
+ * (IP) socket supports the following options:
+ * <blockquote>
+ * <table border>
+ *   <tr>
+ *     <th>Option Name</th>
+ *     <th>Description</th>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#SO_SNDBUF SO_SNDBUF} </td>
+ *     <td> The size of the socket send buffer </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#SO_RCVBUF SO_RCVBUF} </td>
+ *     <td> The size of the socket receive buffer </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#SO_REUSEADDR SO_REUSEADDR} </td>
+ *     <td> Re-use address </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#SO_BROADCAST SO_BROADCAST} </td>
+ *     <td> Allow transmission of broadcast datagrams </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#IP_TOS IP_TOS} </td>
+ *     <td> The Type of Service (ToS) octet in the Internet Protocol (IP) header </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#IP_MULTICAST_IF IP_MULTICAST_IF} </td>
+ *     <td> The network interface for Internet Protocol (IP) multicast datagrams </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#IP_MULTICAST_TTL
+ *       IP_MULTICAST_TTL} </td>
+ *     <td> The <em>time-to-live</em> for Internet Protocol (IP) multicast
+ *       datagrams </td>
+ *   </tr>
+ *   <tr>
+ *     <td> {@link java.net.StandardSocketOption#IP_MULTICAST_LOOP
+ *       IP_MULTICAST_LOOP} </td>
+ *     <td> Loopback for Internet Protocol (IP) multicast datagrams </td>
+ *   </tr>
+ * </table>
+ * </blockquote>
+ * Additional (implementation specific) options may also be supported.
+ *
+ * <p> Asynchronous datagram channels allow more than one read/receive and
+ * write/send to be oustanding at any given time.
+ *
+ * <p> <b>Usage Example:</b>
+ * <pre>
+ *  final AsynchronousDatagramChannel dc = AsynchronousDatagramChannel.open()
+ *      .bind(new InetSocketAddress(4000));
+ *
+ *  // print the source address of all packets that we receive
+ *  dc.receive(buffer, buffer, new CompletionHandler&lt;SocketAddress,ByteBuffer&gt;() {
+ *      public void completed(SocketAddress sa, ByteBuffer buffer) {
+ *          try {
+ *               System.out.println(sa);
+ *
+ *               buffer.clear();
+ *               dc.receive(buffer, buffer, this);
+ *           } catch (...) { ... }
+ *      }
+ *      public void failed(Throwable exc, ByteBuffer buffer) {
+ *          ...
+ *      }
+ *      public void cancelled(ByteBuffer buffer) {
+ *          ...
+ *      }
+ *  });
+ * </pre>
+ *
+ * @since 1.7
+ */
+
+public abstract class AsynchronousDatagramChannel
+    implements AsynchronousByteChannel, MulticastChannel
+{
+    private final AsynchronousChannelProvider provider;
+
+    /**
+     * Initializes a new instance of this class.
+     */
+    protected AsynchronousDatagramChannel(AsynchronousChannelProvider provider) {
+        this.provider = provider;
+    }
+
+    /**
+     * Returns the provider that created this channel.
+     */
+    public final AsynchronousChannelProvider provider() {
+        return provider;
+    }
+
+    /**
+     * Opens an asynchronous datagram channel.
+     *
+     * <p> The new channel is created by invoking the {@link
+     * java.nio.channels.spi.AsynchronousChannelProvider#openAsynchronousDatagramChannel
+     * openAsynchronousDatagramChannel} method on the {@link
+     * java.nio.channels.spi.AsynchronousChannelProvider} object that created
+     * the given group (or the default provider where {@code group} is {@code
+     * null}).
+     *
+     * <p> The {@code family} parameter is used to specify the {@link ProtocolFamily}.
+     * If the datagram channel is to be used for Internet Protocol {@link
+     * MulticastChannel multicasting} then this parameter should correspond to
+     * the address type of the multicast groups that this channel will join.
+     *
+     * @param   family
+     *          The protocol family, or {@code null} to use the default protocol
+     *          family
+     * @param   group
+     *          The group to which the newly constructed channel should be bound,
+     *          or {@code null} for the default group
+     *
+     * @return  A new asynchronous datagram channel
+     *
+     * @throws  UnsupportedOperationException
+     *          If the specified protocol family is not supported. For example,
+     *          suppose the parameter is specified as {@link
+     *          java.net.StandardProtocolFamily#INET6 INET6} but IPv6 is not
+     *          enabled on the platform.
+     * @throws  ShutdownChannelGroupException
+     *          The specified group is shutdown
+     * @throws  IOException
+     *          If an I/O error occurs
+     */
+    public static AsynchronousDatagramChannel open(ProtocolFamily family,
+                                                   AsynchronousChannelGroup group)
+        throws IOException
+    {
+        AsynchronousChannelProvider provider = (group == null) ?
+            AsynchronousChannelProvider.provider() : group.provider();
+        return provider.openAsynchronousDatagramChannel(family, group);
+    }
+
+    /**
+     * Opens an asynchronous datagram channel.
+     *
+     * <p> This method returns an asynchronous datagram channel that is
+     * bound to the <em>default group</em>. This method is equivalent to evaluating
+     * the expression:
+     * <blockquote><pre>
+     * open((ProtocolFamily)null,&nbsp;(AsynchronousChannelGroup)null);
+     * </pre></blockquote>
+     *
+     * @return  A new asynchronous datagram channel
+     *
+     * @throws  IOException
+     *          If an I/O error occurs
+     */
+    public static AsynchronousDatagramChannel open()
+        throws IOException
+    {
+        return open(null, null);
+    }
+
+    // -- Socket-specific operations --
+
+    /**
+     * @throws  AlreadyBoundException               {@inheritDoc}
+     * @throws  UnsupportedAddressTypeException     {@inheritDoc}
+     * @throws  ClosedChannelException              {@inheritDoc}
+     * @throws  IOException                         {@inheritDoc}
+     * @throws  SecurityException
+     *          If a security manager has been installed and its {@link
+     *          SecurityManager#checkListen checkListen} method denies the
+     *          operation
+     */
+    @Override
+    public abstract AsynchronousDatagramChannel bind(SocketAddress local)
+        throws IOException;
+
+    /**
+     * @throws  IllegalArgumentException                {@inheritDoc}
+     * @throws  ClosedChannelException                  {@inheritDoc}
+     * @throws  IOException                             {@inheritDoc}
+     */
+    @Override
+    public abstract <T> AsynchronousDatagramChannel setOption(SocketOption<T> name, T value)
+        throws IOException;
+
+    /**
+     * Returns the remote address to which this channel is connected.
+     *
+     * <p> Where the channel is connected to an Internet Protocol socket address
+     * then the return value from this method is of type {@link
+     * java.net.InetSocketAddress}.
+     *
+     * @return  The remote address; {@code null} if the channel's socket is not
+     *          connected
+     *
+     * @throws  ClosedChannelException
+     *          If the channel is closed
+     * @throws  IOException
+     *          If an I/O error occurs
+     */
+    public abstract SocketAddress getRemoteAddress() throws IOException;
+
+    /**
+     * Connects this channel's socket.
+     *
+     * <p> The channel's socket is configured so that it only receives
+     * datagrams from, and sends datagrams to, the given remote <i>peer</i>
+     * address.  Once connected, datagrams may not be received from or sent to
+     * any other address.  A datagram socket remains connected until it is
+     * explicitly disconnected or until it is closed.
+     *
+     * <p> This method performs exactly the same security checks as the {@link
+     * java.net.DatagramSocket#connect connect} method of the {@link
+     * java.net.DatagramSocket} class.  That is, if a security manager has been
+     * installed then this method verifies that its {@link
+     * java.lang.SecurityManager#checkAccept checkAccept} and {@link
+     * java.lang.SecurityManager#checkConnect checkConnect} methods permit
+     * datagrams to be received from and sent to, respectively, the given
+     * remote address.
+     *
+     * <p> This method may be invoked at any time. Whether it has any effect
+     * on outstanding read or write operations is implementation specific and
+     * therefore not specified.
+     *
+     * @param  remote
+     *         The remote address to which this channel is to be connected
+     *
+     * @return  This datagram channel
+     *
+     * @throws  ClosedChannelException
+     *          If this channel is closed
+     *
+     * @throws  SecurityException
+     *          If a security manager has been installed
+     *          and it does not permit access to the given remote address
+     *
+     * @throws  IOException
+     *          If some other I/O error occurs
+     */
+    public abstract AsynchronousDatagramChannel connect(SocketAddress remote)
+        throws IOException;
+
+    /**
+     * Disconnects this channel's socket.
+     *
+     * <p> The channel's socket is configured so that it can receive datagrams
+     * from, and sends datagrams to, any remote address so long as the security
+     * manager, if installed, permits it.
+     *
+     * <p> This method may be invoked at any time. Whether it has any effect
+     * on outstanding read or write operations is implementation specific and
+     * therefore not specified.
+     *
+     * @return  This datagram channel
+     *
+     * @throws  IOException
+     *          If some other I/O error occurs
+     */
+    public abstract AsynchronousDatagramChannel disconnect() throws IOException;
+
+    /**
+     * Receives a datagram via this channel.
+     *
+     * <p> This method initiates the receiving of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The {@code Future}'s {@link Future#get() get} method returns
+     * the source address of the datagram upon successful completion.
+     *
+     * <p> The datagram is transferred into the given byte buffer starting at
+     * its current position, as if by a regular {@link AsynchronousByteChannel#read
+     * read} operation. If there are fewer bytes remaining in the buffer
+     * than are required to hold the datagram then the remainder of the datagram
+     * is silently discarded.
+     *
+     * <p> If a timeout is specified and the timeout elapses before the operation
+     * completes then the operation completes with the exception {@link
+     * InterruptedByTimeoutException}. When a timeout elapses then the state of
+     * the {@link ByteBuffer} is not defined. The buffers should be discarded or
+     * at least care must be taken to ensure that the buffer is not accessed
+     * while the channel remains open.
+     *
+     * <p> When a security manager has been installed and the channel is not
+     * connected, then it verifies that the source's address and port number are
+     * permitted by the security manager's {@link SecurityManager#checkAccept
+     * checkAccept} method. The permission check is performed with privileges that
+     * are restricted by the calling context of this method. If the permission
+     * check fails then the operation completes with a {@link SecurityException}.
+     * The overhead of this security check can be avoided by first connecting the
+     * socket via the {@link #connect connect} method.
+     *
+     * @param   dst
+     *          The buffer into which the datagram is to be transferred
+     * @param   timeout
+     *          The timeout, or {@code 0L} for no timeout
+     * @param   unit
+     *          The time unit of the {@code timeout} argument
+     * @param   attachment
+     *          The object to attach to the I/O operation; can be {@code null}
+     * @param   handler
+     *          The handler for consuming the result; can be {@code null}
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  IllegalArgumentException
+     *          If the timeout is negative or the buffer is read-only
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    public abstract <A> Future<SocketAddress> receive(ByteBuffer dst,
+                                                      long timeout,
+                                                      TimeUnit unit,
+                                                      A attachment,
+                                                      CompletionHandler<SocketAddress,? super A> handler);
+
+    /**
+     * Receives a datagram via this channel.
+     *
+     * <p> This method initiates the receiving of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The {@code Future}'s {@link Future#get() get} method returns
+     * the source address of the datagram upon successful completion.
+     *
+     * <p> This method is equivalent to invoking {@link
+     * #receive(ByteBuffer,long,TimeUnit,Object,CompletionHandler)} with a
+     * timeout of {@code 0L}.
+     *
+     * @param   dst
+     *          The buffer into which the datagram is to be transferred
+     * @param   attachment
+     *          The object to attach to the I/O operation; can be {@code null}
+     * @param   handler
+     *          The handler for consuming the result; can be {@code null}
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  IllegalArgumentException
+     *          If the buffer is read-only
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    public final <A> Future<SocketAddress> receive(ByteBuffer dst,
+                                                   A attachment,
+                                                   CompletionHandler<SocketAddress,? super A> handler)
+    {
+        return receive(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+    }
+
+    /**
+     * Receives a datagram via this channel.
+     *
+     * <p> This method initiates the receiving of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The {@code Future}'s {@link Future#get() get} method returns
+     * the source address of the datagram upon successful completion.
+     *
+     * <p> This method is equivalent to invoking {@link
+     * #receive(ByteBuffer,long,TimeUnit,Object,CompletionHandler)} with a
+     * timeout of {@code 0L}, and an attachment and completion handler
+     * of {@code null}.
+     *
+     * @param   dst
+     *          The buffer into which the datagram is to be transferred
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  IllegalArgumentException
+     *          If the buffer is read-only
+     */
+    public final <A> Future<SocketAddress> receive(ByteBuffer dst) {
+        return receive(dst, 0L, TimeUnit.MILLISECONDS, null, null);
+    }
+
+    /**
+     * Sends a datagram via this channel.
+     *
+     * <p> This method initiates sending of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The operation sends the remaining bytes in the given buffer as a single
+     * datagram to the given target address. The result of the operation, obtained
+     * by invoking the {@code Future}'s {@link Future#get() get}
+     * method, is the number of bytes sent.
+     *
+     * <p> The datagram is transferred from the byte buffer as if by a regular
+     * {@link AsynchronousByteChannel#write write} operation.
+     *
+     * <p> If a timeout is specified and the timeout elapses before the operation
+     * completes then the operation completes with the exception {@link
+     * InterruptedByTimeoutException}. When a timeout elapses then the state of
+     * the {@link ByteBuffer} is not defined. The buffers should be discarded or
+     * at least care must be taken to ensure that the buffer is not accessed
+     * while the channel remains open.
+     *
+     * <p> If there is a security manager installed and the the channel is not
+     * connected then this method verifies that the target address and port number
+     * are permitted by the security manager's {@link SecurityManager#checkConnect
+     * checkConnect} method.  The overhead of this security check can be avoided
+     * by first connecting the socket via the {@link #connect connect} method.
+     *
+     * @param   src
+     *          The buffer containing the datagram to be sent
+     * @param   target
+     *          The address to which the datagram is to be sent
+     * @param   timeout
+     *          The timeout, or {@code 0L} for no timeout
+     * @param   unit
+     *          The time unit of the {@code timeout} argument
+     * @param   attachment
+     *          The object to attach to the I/O operation; can be {@code null}
+     * @param   handler
+     *          The handler for consuming the result; can be {@code null}
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  UnresolvedAddressException
+     *          If the given remote address is not fully resolved
+     * @throws  UnsupportedAddressTypeException
+     *          If the type of the given remote address is not supported
+     * @throws  IllegalArgumentException
+     *          If the timeout is negative, or if the channel's socket is
+     *          connected to an address that is not equal to {@code target}
+     * @throws  SecurityException
+     *          If a security manager has been installed and it does not permit
+     *          datagrams to be sent to the given address
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    public abstract <A> Future<Integer> send(ByteBuffer src,
+                                             SocketAddress target,
+                                             long timeout,
+                                             TimeUnit unit,
+                                             A attachment,
+                                             CompletionHandler<Integer,? super A> handler);
+
+    /**
+     * Sends a datagram via this channel.
+     *
+     * <p> This method initiates sending of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The operation sends the remaining bytes in the given buffer as a single
+     * datagram to the given target address. The result of the operation, obtained
+     * by invoking the {@code Future}'s {@link Future#get() get}
+     * method, is the number of bytes sent.
+     *
+     * <p> This method is equivalent to invoking {@link
+     * #send(ByteBuffer,SocketAddress,long,TimeUnit,Object,CompletionHandler)}
+     * with a timeout of {@code 0L}.
+     *
+     * @param   src
+     *          The buffer containing the datagram to be sent
+     * @param   target
+     *          The address to which the datagram is to be sent
+     * @param   attachment
+     *          The object to attach to the I/O operation; can be {@code null}
+     * @param   handler
+     *          The handler for consuming the result; can be {@code null}
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  UnresolvedAddressException
+     *          If the given remote address is not fully resolved
+     * @throws  UnsupportedAddressTypeException
+     *          If the type of the given remote address is not supported
+     * @throws  IllegalArgumentException
+     *          If the channel's socket is connected and is connected to an
+     *          address that is not equal to {@code target}
+     * @throws  SecurityException
+     *          If a security manager has been installed and it does not permit
+     *          datagrams to be sent to the given address
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    public final <A> Future<Integer> send(ByteBuffer src,
+                                          SocketAddress target,
+                                          A attachment,
+                                          CompletionHandler<Integer,? super A> handler)
+    {
+        return send(src, target, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+    }
+
+    /**
+     * Sends a datagram via this channel.
+     *
+     * <p> This method initiates sending of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The operation sends the remaining bytes in the given buffer as a single
+     * datagram to the given target address. The result of the operation, obtained
+     * by invoking the {@code Future}'s {@link Future#get() get}
+     * method, is the number of bytes sent.
+     *
+     * <p> This method is equivalent to invoking {@link
+     * #send(ByteBuffer,SocketAddress,long,TimeUnit,Object,CompletionHandler)}
+     * with a timeout of {@code 0L} and an attachment and completion handler
+     * of {@code null}.
+     *
+     * @param   src
+     *          The buffer containing the datagram to be sent
+     * @param   target
+     *          The address to which the datagram is to be sent
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  UnresolvedAddressException
+     *          If the given remote address is not fully resolved
+     * @throws  UnsupportedAddressTypeException
+     *          If the type of the given remote address is not supported
+     * @throws  IllegalArgumentException
+     *          If the channel's socket is connected and is connected to an
+     *          address that is not equal to {@code target}
+     * @throws  SecurityException
+     *          If a security manager has been installed and it does not permit
+     *          datagrams to be sent to the given address
+     */
+    public final Future<Integer> send(ByteBuffer src, SocketAddress target) {
+        return send(src, target, 0L, TimeUnit.MILLISECONDS, null, null);
+    }
+
+    /**
+     * Receives a datagram via this channel.
+     *
+     * <p> This method initiates the receiving of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The {@code Future}'s {@link Future#get() get} method returns
+     * the number of bytes transferred upon successful completion.
+     *
+     * <p> This method may only be invoked if this channel is connected, and it
+     * only accepts datagrams from the peer that the channel is connected too.
+     * The datagram is transferred into the given byte buffer starting at
+     * its current position and exactly as specified in the {@link
+     * AsynchronousByteChannel} interface. If there are fewer bytes
+     * remaining in the buffer than are required to hold the datagram then the
+     * remainder of the datagram is silently discarded.
+     *
+     * <p> If a timeout is specified and the timeout elapses before the operation
+     * completes then the operation completes with the exception {@link
+     * InterruptedByTimeoutException}. When a timeout elapses then the state of
+     * the {@link ByteBuffer} is not defined. The buffers should be discarded or
+     * at least care must be taken to ensure that the buffer is not accessed
+     * while the channel remains open.
+     *
+     * @param   dst
+     *          The buffer into which the datagram is to be transferred
+     * @param   timeout
+     *          The timeout, or {@code 0L} for no timeout
+     * @param   unit
+     *          The time unit of the {@code timeout} argument
+     * @param   attachment
+     *          The object to attach to the I/O operation; can be {@code null}
+     * @param   handler
+     *          The handler for consuming the result; can be {@code null}
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  IllegalArgumentException
+     *          If the timeout is negative or buffer is read-only
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    public abstract <A> Future<Integer> read(ByteBuffer dst,
+                                             long timeout,
+                                             TimeUnit unit,
+                                             A attachment,
+                                             CompletionHandler<Integer,? super A> handler);
+
+    /**
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    @Override
+    public final <A> Future<Integer> read(ByteBuffer dst,
+                                          A attachment,
+                                          CompletionHandler<Integer,? super A> handler)
+    {
+        return read(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+    }
+
+    /**
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    @Override
+    public final Future<Integer> read(ByteBuffer dst) {
+        return read(dst, 0L, TimeUnit.MILLISECONDS, null, null);
+    }
+
+    /**
+     * Writes a datagram to this channel.
+     *
+     * <p> This method initiates sending of a datagram, returning a
+     * {@code Future} representing the pending result of the operation.
+     * The operation sends the remaining bytes in the given buffer as a single
+     * datagram. The result of the operation, obtained by invoking the
+     * {@code Future}'s {@link Future#get() get} method, is the
+     * number of bytes sent.
+     *
+     * <p> The datagram is transferred from the byte buffer as if by a regular
+     * {@link AsynchronousByteChannel#write write} operation.
+     *
+     * <p> This method may only be invoked if this channel is connected,
+     * in which case it sends datagrams directly to the socket's peer.  Otherwise
+     * it behaves exactly as specified in the {@link
+     * AsynchronousByteChannel} interface.
+     *
+     * <p> If a timeout is specified and the timeout elapses before the operation
+     * completes then the operation completes with the exception {@link
+     * InterruptedByTimeoutException}. When a timeout elapses then the state of
+     * the {@link ByteBuffer} is not defined. The buffers should be discarded or
+     * at least care must be taken to ensure that the buffer is not accessed
+     * while the channel remains open.
+     *
+     * @param   src
+     *          The buffer containing the datagram to be sent
+     * @param   timeout
+     *          The timeout, or {@code 0L} for no timeout
+     * @param   unit
+     *          The time unit of the {@code timeout} argument
+     * @param   attachment
+     *          The object to attach to the I/O operation; can be {@code null}
+     * @param   handler
+     *          The handler for consuming the result; can be {@code null}
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  IllegalArgumentException
+     *          If the timeout is negative
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    public abstract <A> Future<Integer> write(ByteBuffer src,
+                                              long timeout,
+                                              TimeUnit unit,
+                                              A attachment,
+                                              CompletionHandler<Integer,? super A> handler);
+    /**
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    @Override
+    public final <A> Future<Integer> write(ByteBuffer src,
+                                           A attachment,
+                                           CompletionHandler<Integer,? super A> handler)
+    {
+        return write(src, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+    }
+
+    /**
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If a handler is specified, and the channel group is shutdown
+     */
+    @Override
+    public final Future<Integer> write(ByteBuffer src) {
+        return write(src, 0L, TimeUnit.MILLISECONDS, null, null);
+    }
+}