https://openjdk.java.net/ 
/*
 * Copyright (c) 2009, 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
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 *
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package com.sun.nio.sctp;

import java.net.SocketAddress;
import java.net.InetAddress;
import java.io.IOException;
import java.util.Set;
import java.nio.ByteBuffer;
import java.nio.channels.spi.AbstractSelectableChannel;
import java.nio.channels.spi.SelectorProvider;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.NotYetBoundException;
import java.nio.channels.SelectionKey;


A selectable channel for message-oriented SCTP sockets.

 An SCTP multi channel supports many associations on a single socket. An SctpMultiChannel is created by invoking the open method of this class. A newly-created channel is open but not yet bound. An attempt to invoke the receive method of an unbound channel will cause the NotYetBoundException to be thrown. An attempt to invoke the send method of an unbound channel will cause it to first invoke the bind method. The address(es) that the channel's socket is bound to can be retrieved by calling getAllLocalAddresses. 
 Messages may be sent and received without explicitly setting up an association with the remote peer. The channel will implicitly setup a new association whenever it sends or receives a message from a remote peer if there is not already an association with that peer. Upon successful association setup, an 
association changed notification will be put to the SCTP stack with its event parameter set to 
COMM_UP. This notification can be received by invoking 
receive. 
 Socket options are configured using the setOption method. An SctpMultiChannel supports the following options: 



  

    Option Name
    Description
  

  

     
                                         SCTP_DISABLE_FRAGMENTS 
     Enables or disables message fragmentation 
  

  

     
                                         SCTP_EXPLICIT_COMPLETE 
     Enables or disables explicit message completion 
  

   

     
                                         SCTP_FRAGMENT_INTERLEAVE 
     Controls how the presentation of messages occur for the message
         receiver 
  

  

     
                                         SCTP_INIT_MAXSTREAMS 
     The maximum number of streams requested by the local endpoint during
         association initialization 
  

  

     SCTP_NODELAY 
     Enables or disable a Nagle-like algorithm 
  

  

     
                                         SCTP_PRIMARY_ADDR 
     Requests that the local SCTP stack use the given peer address as the
         association primary 
  

  

     
                                         SCTP_SET_PEER_PRIMARY_ADDR 
     Requests that the peer mark the enclosed address as the association
         primary 
  

  

     
                                         SO_SNDBUF 
     The size of the socket send buffer 
  

  

     
                                         SO_RCVBUF 
     The size of the socket receive buffer 
  

  

     
                                         SO_LINGER 
     Linger on close if data is present (when configured in blocking mode
         only) 
  




 Additional (implementation specific) options may also be supported. The list of options supported is obtained by invoking the 
supportedOptions method. 
 SCTP multi channels are safe for use by multiple concurrent threads.
They support concurrent sending and receiving, though at most one thread may be
sending and at most one thread may be receiving at any given time.

Since:1.7
/**
 * A selectable channel for message-oriented SCTP sockets.
 *
 * <P> An SCTP multi channel supports many associations on a single socket.
 * An {@code SctpMultiChannel} is created by invoking the
 * {@link #open open} method of this class. A newly-created channel is open but
 * not yet bound. An attempt to invoke the {@link #receive receive} method of an
 * unbound channel will cause the {@link NotYetBoundException}
 * to be thrown. An attempt to invoke the {@link #send send} method of an
 * unbound channel will cause it to first invoke the {@link #bind bind} method.
 * The address(es) that the channel's socket is bound to can be retrieved by
 * calling {@link #getAllLocalAddresses getAllLocalAddresses}.
 *
 * <P> Messages may be sent and received without explicitly setting up an
 * association with the remote peer. The channel will implicitly setup
 * a new association whenever it sends or receives a message from a remote
 * peer if there is not already an association with that peer. Upon successful
 * association setup, an {@link AssociationChangeNotification
 * association changed} notification will be put to the SCTP stack with its
 * {@code event} parameter set to {@link
 * AssociationChangeNotification.AssocChangeEvent#COMM_UP
 * COMM_UP}. This notification can be received by invoking {@link #receive
 * receive}.
 *
 * <P> Socket options are configured using the
 * {@link #setOption(SctpSocketOption,Object,Association) setOption} method. An
 * {@code SctpMultiChannel} supports the following options:
 * <blockquote>
 * <table border>
 *   <tr>
 *     <th>Option Name</th>
 *     <th>Description</th>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_DISABLE_FRAGMENTS
 *                                          SCTP_DISABLE_FRAGMENTS} </td>
 *     <td> Enables or disables message fragmentation </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE
 *                                          SCTP_EXPLICIT_COMPLETE} </td>
 *     <td> Enables or disables explicit message completion </td>
 *   </tr>
 *    <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE
 *                                          SCTP_FRAGMENT_INTERLEAVE} </td>
 *     <td> Controls how the presentation of messages occur for the message
 *          receiver </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_INIT_MAXSTREAMS
 *                                          SCTP_INIT_MAXSTREAMS} </td>
 *     <td> The maximum number of streams requested by the local endpoint during
 *          association initialization </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_NODELAY SCTP_NODELAY} </td>
 *     <td> Enables or disable a Nagle-like algorithm </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_PRIMARY_ADDR
 *                                          SCTP_PRIMARY_ADDR} </td>
 *     <td> Requests that the local SCTP stack use the given peer address as the
 *          association primary </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SCTP_SET_PEER_PRIMARY_ADDR
 *                                          SCTP_SET_PEER_PRIMARY_ADDR} </td>
 *     <td> Requests that the peer mark the enclosed address as the association
 *          primary </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SO_SNDBUF
 *                                          SO_SNDBUF} </td>
 *     <td> The size of the socket send buffer </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SO_RCVBUF
 *                                          SO_RCVBUF} </td>
 *     <td> The size of the socket receive buffer </td>
 *   </tr>
 *   <tr>
 *     <td> {@link SctpStandardSocketOptions#SO_LINGER
 *                                          SO_LINGER} </td>
 *     <td> Linger on close if data is present (when configured in blocking mode
 *          only) </td>
 *   </tr>
 * </table>
 * </blockquote>
 * Additional (implementation specific) options may also be supported. The list
 * of options supported is obtained by invoking the {@link #supportedOptions()
 * supportedOptions} method.
 *
 * <p> SCTP multi channels are safe for use by multiple concurrent threads.
 * They support concurrent sending and receiving, though at most one thread may be
 * sending and at most one thread may be receiving at any given time.
 *
 * @since 1.7
 */
public abstract class SctpMultiChannel
    extends AbstractSelectableChannel
{
    
Initializes a new instance of this class.

Params:
  • provider – 
        The selector provider for this channel
/**
     * Initializes a new instance of this class.
     *
     * @param  provider
     *         The selector provider for this channel
     */
    protected SctpMultiChannel(SelectorProvider provider) {
        super(provider);
    }

    
Opens an SCTP multi channel.

 The new channel is unbound.

Throws:
Returns: A new SCTP multi channel
/**
     * Opens an SCTP multi channel.
     *
     * <P> The new channel is unbound.
     *
     * @return  A new SCTP multi channel
     *
     * @throws UnsupportedOperationException
     *         If the SCTP protocol is not supported
     *
     * @throws  IOException
     *          If an I/O error occurs
     */
    public static SctpMultiChannel open() throws
        IOException {
        return new sun.nio.ch.SctpMultiChannelImpl((SelectorProvider)null);
    }

    
Returns the open associations on this channel's socket.

 Only associations whose 
COMM_UP association change event has been received are included in the returned set of associations. Associations for which a COMM_LOST or SHUTDOWN association change event have been receive are removed from the set of associations. 
 The returned set of associations is a snapshot of the open
associations at the time that this method is invoked.

Throws:
Returns: A Set containing the open associations, or an empty Set if there are none.
/**
     * Returns the open associations on this channel's socket.
     *
     * <P> Only associations whose {@link AssociationChangeNotification.AssocChangeEvent#COMM_UP
     * COMM_UP} association change event has been received are included
     * in the returned set of associations. Associations for which a
     * {@link AssociationChangeNotification.AssocChangeEvent#COMM_LOST COMM_LOST} or {@link
     * AssociationChangeNotification.AssocChangeEvent#SHUTDOWN SHUTDOWN} association change
     * event have been receive are removed from the set of associations.
     *
     * <P> The returned set of associations is a snapshot of the open
     * associations at the time that this method is invoked.
     *
     * @return  A {@code Set} containing the open associations, or an empty
     *          {@code Set} if there are none.
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract Set<Association> associations()
        throws IOException;

    
Binds the channel's socket to a local address and configures the socket
to listen for connections.

 This method is used to establish a relationship between the socket and the local address. Once a relationship is established then the socket remains bound until the channel is closed. This relationship may not necesssarily be with the address local as it may be removed by unbindAddress, but there will always be at least one local address bound to the channel's socket once an invocation of this method successfully completes. 
 Once the channel's socket has been successfully bound to a specific address, that is not automatically assigned, more addresses may be bound to it using bindAddress, or removed using unbindAddress. 
 The backlog parameter is the maximum number of pending connections on the socket. Its exact semantics are implementation specific. An implementation may impose an implementation specific maximum length or may choose to ignore the parameter. If the backlog parameter has the value 0, or a negative value, then an implementation specific default is used. 
Params:
  • local –  The local address to bind the socket, or null to bind the socket to an automatically assigned socket address
  • backlog – 
        The maximum number number of pending connections
Throws:
Returns: This channel
/**
     * Binds the channel's socket to a local address and configures the socket
     * to listen for connections.
     *
     * <P> This method is used to establish a relationship between the socket
     * and the local address. Once a relationship is established then
     * the socket remains bound until the channel is closed. This relationship
     * may not necesssarily be with the address {@code local} as it may be removed
     * by {@link #unbindAddress unbindAddress}, but there will always be at least one local
     * address bound to the channel's socket once an invocation of this method
     * successfully completes.
     *
     * <P> Once the channel's socket has been successfully bound to a specific
     * address, that is not automatically assigned, more addresses
     * may be bound to it using {@link #bindAddress bindAddress}, or removed
     * using {@link #unbindAddress unbindAddress}.
     *
     * <P> The backlog parameter is the maximum number of pending connections on
     * the socket. Its exact semantics are implementation specific. An implementation
     * may impose an implementation specific maximum length or may choose to ignore
     * the parameter. If the backlog parameter has the value {@code 0}, or a negative
     * value, then an implementation specific default is used.
     *
     * @param  local
     *         The local address to bind the socket, or {@code null} to
     *         bind the socket to an automatically assigned socket address
     *
     * @param  backlog
     *         The maximum number number of pending connections
     *
     * @return  This channel
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  java.nio.channels.AlreadyBoundException
     *          If this channel is already bound
     *
     * @throws  java.nio.channels.UnsupportedAddressTypeException
     *          If the type of the given address is not supported
     *
     * @throws  SecurityException
     *          If a security manager has been installed and its {@link
     *          java.lang.SecurityManager#checkListen(int) checkListen} method
     *          denies the operation
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract SctpMultiChannel bind(SocketAddress local,
                                          int backlog)
        throws IOException;

    
Binds the channel's socket to a local address and configures the socket
to listen for connections.

 This method works as if invoking it were equivalent to evaluating the
expression:

bind(local, 0);



Params:
  • local –  The local address to bind the socket, or null to bind the socket to an automatically assigned socket address
Throws:
Returns: This channel
/**
     * Binds the channel's socket to a local address and configures the socket
     * to listen for connections.
     *
     * <P> This method works as if invoking it were equivalent to evaluating the
     * expression:
     * <blockquote><pre>
     * bind(local, 0);
     * </pre></blockquote>
     *
     * @param  local
     *         The local address to bind the socket, or {@code null} to
     *         bind the socket to an automatically assigned socket address
     *
     * @return  This channel
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  java.nio.channels.AlreadyBoundException
     *          If this channel is already bound
     *
     * @throws  java.nio.channels.UnsupportedAddressTypeException
     *          If the type of the given address is not supported
     *
     * @throws  SecurityException
     *          If a security manager has been installed and its {@link
     *          java.lang.SecurityManager#checkListen(int) checkListen} method
     *          denies the operation
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public final SctpMultiChannel bind(SocketAddress local)
        throws IOException {
        return bind(local, 0);
    }

    
Adds the given address to the bound addresses for the channel's
socket.

 The given address must not be the wildcard address. The channel must be first bound using bind before invoking this method, otherwise NotYetBoundException is thrown. The bind method takes a SocketAddress as its argument which typically contains a port number as well as an address. Addresses subquently bound using this method are simply addresses as the SCTP port number remains the same for the lifetime of the channel. 
 New associations setup after this method successfully completes
will be associated with the given address. Adding addresses to existing
associations is optional functionality. If the endpoint supports
dynamic address reconfiguration then it may send the appropriate message
to the peer to change the peers address lists.

Params:
  • address – 
        The address to add to the bound addresses for the socket
Throws:
Returns: This channel
/**
     * Adds the given address to the bound addresses for the channel's
     * socket.
     *
     * <P> The given address must not be the {@link
     * java.net.InetAddress#isAnyLocalAddress wildcard} address.
     * The channel must be first bound using {@link #bind bind} before
     * invoking this method, otherwise {@link NotYetBoundException} is thrown.
     * The {@link #bind bind} method takes a {@code SocketAddress} as its
     * argument which typically contains a port number as well as an address.
     * Addresses subquently bound using this method are simply addresses as the
     * SCTP port number remains the same for the lifetime of the channel.
     *
     * <P> New associations setup after this method successfully completes
     * will be associated with the given address. Adding addresses to existing
     * associations is optional functionality. If the endpoint supports
     * dynamic address reconfiguration then it may send the appropriate message
     * to the peer to change the peers address lists.
     *
     * @param  address
     *         The address to add to the bound addresses for the socket
     *
     * @return  This channel
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  NotYetBoundException
     *          If this channel is not yet bound
     *
     * @throws  java.nio.channels.AlreadyBoundException
     *          If this channel is already bound to the given address
     *
     * @throws  IllegalArgumentException
     *          If address is {@code null} or the {@link
     *          java.net.InetAddress#isAnyLocalAddress wildcard} address
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract SctpMultiChannel bindAddress(InetAddress address)
         throws IOException;

    
Removes the given address from the bound addresses for the channel's
socket.

 The given address must not be the wildcard address. The channel must be first bound using bind before invoking this method, otherwise NotYetBoundException is thrown. 
 If this method is invoked on a channel that does not have address as one of its bound addresses, or that has only one local address bound to it, then this method throws IllegalUnbindException. 
 The initial address that the channel's socket is bound to using bind may be removed from the bound addresses for the channel's socket. 
 New associations setup after this method successfully completes
will not be associated with the given address. Removing addresses from
existing associations is optional functionality. If the endpoint supports
dynamic address reconfiguration then it may send the appropriate message
to the peer to change the peers address lists.

Params:
  • address – 
        The address to remove from the bound addresses for the socket
Throws:
Returns: This channel
/**
     * Removes the given address from the bound addresses for the channel's
     * socket.
     *
     * <P> The given address must not be the {@link
     * java.net.InetAddress#isAnyLocalAddress wildcard} address.
     * The channel must be first bound using {@link #bind bind} before
     * invoking this method, otherwise {@link NotYetBoundException} is thrown.
     *
     * <P> If this method is invoked on a channel that does
     * not have {@code address} as one of its bound addresses, or that has only
     * one local address bound to it, then this method throws
     * {@link IllegalUnbindException}.
     *
     * <P> The initial address that the channel's socket is bound to using
     * {@link #bind bind} may be removed from the bound addresses for the
     * channel's socket.
     *
     * <P> New associations setup after this method successfully completes
     * will not be associated with the given address. Removing addresses from
     * existing associations is optional functionality. If the endpoint supports
     * dynamic address reconfiguration then it may send the appropriate message
     * to the peer to change the peers address lists.
     *
     * @param  address
     *         The address to remove from the bound addresses for the socket
     *
     * @return  This channel
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  NotYetBoundException
     *          If this channel is not yet bound
     *
     * @throws  IllegalUnbindException
     *          {@code address} is not bound to the channel's socket, or the
     *          channel has only one address  bound to it
     *
     * @throws  IllegalArgumentException
     *          If address is {@code null} or the {@link
     *          java.net.InetAddress#isAnyLocalAddress wildcard} address
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract SctpMultiChannel unbindAddress(InetAddress address)
         throws IOException;

    
Returns all of the socket addresses to which this channel's socket is
bound.

Throws:
Returns: All the socket addresses that this channel's socket is bound to, or an empty Set if the channel's socket is not bound
/**
     * Returns all of the socket addresses to which this channel's socket is
     * bound.
     *
     * @return  All the socket addresses that this channel's socket is
     *          bound to, or an empty {@code Set} if the channel's socket is not
     *          bound
     *
     * @throws  ClosedChannelException
     *          If the channel is closed
     *
     * @throws  IOException
     *          If an I/O error occurs
     */
    public abstract Set<SocketAddress> getAllLocalAddresses()
        throws IOException;

    
Returns all of the remote addresses to which the given association on
this channel's socket is connected.

Throws:
Returns: All of the remote addresses for the given association, or an empty Set if the association has been shutdown
/**
     * Returns all of the remote addresses to which the given association on
     * this channel's socket is connected.
     *
     * @return  All of the remote addresses for the given association, or
     *          an empty {@code Set} if the association has been shutdown
     *
     * @throws  ClosedChannelException
     *          If the channel is closed
     *
     * @throws  IOException
     *          If an I/O error occurs
     */
    public abstract Set<SocketAddress> getRemoteAddresses(Association association)
        throws IOException;

    
Shutdown an association without closing the channel.

Params:
  • association – 
        The association to shutdown
Throws:
Returns: This channel
/**
     * Shutdown an association without closing the channel.
     *
     * @param  association
     *         The association to shutdown
     *
     * @return  This channel
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract SctpMultiChannel shutdown(Association association)
            throws IOException;

    
Returns the value of a socket option.

 Note that some options are retrieved on the channel's socket, therefore the association parameter is not applicable and will be ignored if given. However, if the option is association specific then the association must be given. 
Params:
  • name – 
        The socket option
  • association –  The association whose option should be retrieved, or null if this option should be retrieved at the channel's socket level.
Throws:
See Also:
Returns: The value of the socket option. A value of null may be a valid value for some socket options.
/**
     * Returns the value of a socket option.
     *
     * <P> Note that some options are retrieved on the channel's socket,
     * therefore the {@code association} parameter is not applicable and will be
     * ignored if given. However, if the option is association specific then the
     * association must be given.
     *
     * @param  name
     *         The socket option
     *
     * @param  association
     *         The association whose option should be retrieved, or {@code null}
     *         if this option should be retrieved at the channel's socket level.
     *
     * @return  The value of the socket option. A value of {@code null} may be
     *          a valid value for some socket options.
     *
     * @throws  UnsupportedOperationException
     *          If the socket option is not supported by this channel
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  IOException
     *          If an I/O error occurs
     *
     * @see SctpStandardSocketOptions
     */
    public abstract <T> T getOption(SctpSocketOption<T> name,
                                    Association association)
        throws IOException;

    
Sets the value of a socket option.

 Note that some options are retrieved on the channel's socket, therefore the association parameter is not applicable and will be ignored if given. However, if the option is association specific then the association must be given. 
Params:
  • name – 
         The socket option
  • association –  The association whose option should be set, or null if this option should be set at the channel's socket level.
  • value –  The value of the socket option. A value of null may be a valid value for some socket options.
Throws:
See Also:
Returns: This channel
/**
     * Sets the value of a socket option.
     *
     * <P> Note that some options are retrieved on the channel's socket,
     * therefore the {@code association} parameter is not applicable and will be
     * ignored if given. However, if the option is association specific then the
     * association must be given.
     *
     * @param   name
     *          The socket option
     *
     * @param  association
     *         The association whose option should be set, or {@code null}
     *         if this option should be set at the channel's socket level.
     *
     * @param   value
     *          The value of the socket option. A value of {@code null} may be
     *          a valid value for some socket options.
     *
     * @return  This channel
     *
     * @throws  UnsupportedOperationException
     *          If the socket option is not supported by this channel
     *
     * @throws  IllegalArgumentException
     *          If the value is not a valid value for this socket option
     *
     * @throws  ClosedChannelException
     *          If this channel is closed
     *
     * @throws  IOException
     *          If an I/O error occurs
     *
     * @see SctpStandardSocketOptions
     */
    public abstract <T> SctpMultiChannel setOption(SctpSocketOption<T> name,
                                                   T value,
                                                   Association association)
         throws IOException;

     
Returns a set of the socket options supported by this channel.

 This method will continue to return the set of options even after the
channel has been closed.

Returns: A set of the socket options supported by this channel
/**
     * Returns a set of the socket options supported by this channel.
     *
     * <P> This method will continue to return the set of options even after the
     * channel has been closed.
     *
     * @return  A set of the socket options supported by this channel
     */
    public abstract Set<SctpSocketOption<?>> supportedOptions();

    
Returns an operation set identifying this channel's supported operations.

 SCTP multi channels support reading, and writing, so this method returns (SelectionKey.OP_READ | SelectionKey.OP_WRITE). 


Returns: The valid-operation set
/**
     * Returns an operation set identifying this channel's supported operations.
     *
     * <P> SCTP multi channels support reading, and writing, so this
     * method returns
     * {@code (}{@link SelectionKey#OP_READ} {@code |}&nbsp;{@link
     * SelectionKey#OP_WRITE}{@code )}.  </p>
     *
     * @return  The valid-operation set
     */
    @Override
    public final int validOps() {
        return (SelectionKey.OP_READ |
                SelectionKey.OP_WRITE );
    }

    
Receives a message and/or handles a notification via this channel.

 If a message or notification is immediately available, or if this channel is in blocking mode and one eventually becomes available, then the message or notification is returned or handled, respectively. If this channel is in non-blocking mode and a message or notification is not immediately available then this method immediately returns null. 
 If this method receives a message it is copied into the given byte buffer and an MessageInfo is returned. The message is transferred into the given byte buffer starting at its current position and the buffers position is incremented by the number of bytes read. If there are fewer bytes remaining in the buffer than are required to hold the message, or the underlying input buffer does not contain the complete message, then an invocation of isComplete on the returned 
MessageInfo will return false, and more invocations of this method will be necessary to completely consume the messgae. Only one message at a time will be partially delivered in any stream. The socket option 
SCTP_FRAGMENT_INTERLEAVE controls various aspects of what interlacing of messages occurs. 
 If this method receives a notification then the appropriate method of the given handler, if there is one, is invoked. If the handler returns CONTINUE then this method will try to receive another message/notification, otherwise, if RETURN is returned this method will return null. If an uncaught exception is thrown by the handler it will be propagated up the stack through this method. 
 If a security manager has been installed then for each new association setup this method verifies that the associations source address and port number are permitted by the security manager's checkAccept method. 
 This method may be invoked at any time. If another thread has already initiated a receive operation upon this channel, then an invocation of this method will block until the first operation is complete. The given handler is invoked without holding any locks used to enforce the above synchronization policy, that way handlers will not stall other threads from receiving. A handler should not invoke the receive method of this channel, if it does an IllegalReceiveException will be thrown. 
Params:
  • buffer – 
        The buffer into which bytes are to be transferred
  • attachment –  The object to attach to the receive operation; can be null
  • handler –  A handler to handle notifications from the SCTP stack, or null to ignore any notifications.
Throws:
Returns: The MessageInfo, null if this channel is in non-blocking mode and no messages are immediately available or the notification handler returns RETURN after handling a notification
/**
     * Receives a message and/or handles a notification via this channel.
     *
     * <P> If a message or notification is immediately available, or if this
     * channel is in blocking mode and one eventually becomes available, then
     * the message or notification is returned or handled, respectively. If this
     * channel is in non-blocking mode and a message or notification is not
     * immediately available then this method immediately returns {@code null}.
     *
     * <P> If this method receives a message it is copied into the given byte
     * buffer and an {@link MessageInfo} is returned.
     * The message is transferred into the given byte buffer starting at its
     * current position and the buffers position is incremented by the number of
     * bytes read. If there are fewer bytes remaining in the buffer than are
     * required to hold the message, or the underlying input buffer does not
     * contain the complete message, then an invocation of {@link
     * MessageInfo#isComplete isComplete} on the returned {@code
     * MessageInfo} will return {@code false}, and more invocations of this
     * method will be necessary to completely consume the messgae. Only
     * one message at a time will be partially delivered in any stream. The
     * socket option {@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE
     * SCTP_FRAGMENT_INTERLEAVE} controls various aspects of what interlacing of
     * messages occurs.
     *
     * <P> If this method receives a notification then the appropriate method of
     * the given handler, if there is one, is invoked. If the handler returns {@link
     * HandlerResult#CONTINUE CONTINUE} then this method will try to receive another
     * message/notification, otherwise, if {@link HandlerResult#RETURN RETURN} is returned
     * this method will return {@code null}. If an uncaught exception is thrown by the
     * handler it will be propagated up the stack through this method.
     *
     * <P> If a security manager has been installed then for each new association
     * setup this method verifies that the associations source address and port
     * number are permitted by the security manager's {@link
     * java.lang.SecurityManager#checkAccept(String,int) checkAccept} method.
     *
     * <P> This method may be invoked at any time. If another thread has
     * already initiated a receive operation upon this channel, then an
     * invocation of this method will block until the first operation is
     * complete. The given handler is invoked without holding any locks used
     * to enforce the above synchronization policy, that way handlers
     * will not stall other threads from receiving. A handler should not invoke
     * the {@code receive} method of this channel, if it does an
     * {@link IllegalReceiveException} will be thrown.
     *
     * @param  buffer
     *         The buffer into which bytes are to be transferred
     *
     * @param  attachment
     *         The object to attach to the receive operation; can be
     *         {@code null}
     *
     * @param  handler
     *         A handler to handle notifications from the SCTP stack, or
     *         {@code null} to ignore any notifications.
     *
     * @return  The {@code MessageInfo}, {@code null} if this channel is in
     *          non-blocking mode and no messages are immediately available or
     *          the notification handler returns {@code RETURN} after handling
     *          a notification
     *
     * @throws  java.nio.channels.ClosedChannelException
     *          If this channel is closed
     *
     * @throws  java.nio.channels.AsynchronousCloseException
     *          If another thread closes this channel
     *          while the read operation is in progress
     *
     * @throws  java.nio.channels.ClosedByInterruptException
     *          If another thread interrupts the current thread
     *          while the read operation is in progress, thereby
     *          closing the channel and setting the current thread's
     *          interrupt status
     *
     * @throws  NotYetBoundException
     *          If this channel is not yet bound
     *
     * @throws  IllegalReceiveException
     *          If the given handler invokes the {@code receive} method of this
     *          channel
     *
     * @throws  SecurityException
     *          If a security manager has been installed and it does not permit
     *          new associations to be accepted from the message's sender
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract <T> MessageInfo receive(ByteBuffer buffer,
                                            T attachment,
                                            NotificationHandler<T> handler)
        throws IOException;

    
Sends a message via this channel.

 If this channel is unbound then this method will invoke bind(null, 0) before sending any data. 
 If there is no association existing between this channel's socket and the intended receiver, identified by the address in the given messageInfo, then one will be automatically setup to the intended receiver. This is considered to be Implicit Association Setup. Upon successful association setup, an association changed notification will be put to the SCTP stack with its event parameter set to COMM_UP . This notification can be received by invoking 
receive. 
 If this channel is in blocking mode, there is sufficient room in the underlying output buffer, then the remaining bytes in the given byte buffer are transmitted as a single message. Sending a message is atomic unless explicit message completion SCTP_EXPLICIT_COMPLETE socket option is enabled on this channel's socket. 
 If this channel is in non-blocking mode, there is sufficient room in the underlying output buffer, and an implicit association setup is required, then the remaining bytes in the given byte buffer are transmitted as a single message, subject to SCTP_EXPLICIT_COMPLETE. If for any reason the message cannot be delivered an association
changed notification is put on the SCTP stack with its event parameter set to CANT_START. 
 The message is transferred from the byte buffer as if by a regular 
write operation. 
 If a security manager has been installed then for each new association setup this method verifies that the given remote peers address and port number are permitted by the security manager's checkConnect method. 
 This method may be invoked at any time. If another thread has already
initiated a send operation upon this channel, then an invocation of
this method will block until the first operation is complete.

Params:
  • buffer – 
        The buffer containing the message to be sent
  • messageInfo – 
        Ancillary data about the message to be sent
Throws:
  • InvalidStreamExcepton –  If streamNumber is negative, or if an association already exists and streamNumber is greater than the maximum number of outgoing streams
  • ClosedChannelException – 
         If this channel is closed
  • AsynchronousCloseException – 
         If another thread closes this channel
         while the read operation is in progress
  • ClosedByInterruptException – 
         If another thread interrupts the current thread
         while the read operation is in progress, thereby
         closing the channel and setting the current thread's
         interrupt status
  • SecurityException – 
         If a security manager has been installed and it does not permit
         new associations to be setup with the the messages's address
  • IOException – 
         If some other I/O error occurs
Returns: The number of bytes sent, which will be either the number of
         bytes that were remaining in the messages buffer when this method
         was invoked or, if this channel is non-blocking, may be zero if
         there was insufficient room for the message in the underlying
         output buffer
/**
     * Sends a message via this channel.
     *
     * <P> If this channel is unbound then this method will invoke {@link
     * #bind(SocketAddress, int) bind(null, 0)} before sending any data.
     *
     * <P> If there is no association existing between this channel's socket
     * and the intended receiver, identified by the address in the given messageInfo, then one
     * will be automatically setup to the intended receiver. This is considered
     * to be Implicit Association Setup. Upon successful association setup, an
     * {@link AssociationChangeNotification association changed}
     * notification will be put to the SCTP stack with its {@code event} parameter set
     * to {@link AssociationChangeNotification.AssocChangeEvent#COMM_UP COMM_UP}
     * . This notification can be received by invoking {@link #receive
     * receive}.
     *
     * <P> If this channel is in blocking mode, there is sufficient room in the
     * underlying output buffer, then the remaining bytes in the given byte
     * buffer are transmitted as a single message. Sending a message
     * is atomic unless explicit message completion {@link
     * SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE SCTP_EXPLICIT_COMPLETE}
     * socket option is enabled on this channel's socket.
     *
     * <P> If this channel is in non-blocking mode, there is sufficient room
     * in the underlying output buffer, and an implicit association setup is
     * required, then the remaining bytes in the given byte buffer are
     * transmitted as a single message, subject to {@link
     * SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE SCTP_EXPLICIT_COMPLETE}.
     * If for any reason the message cannot
     * be delivered an {@link AssociationChangeNotification association
     * changed} notification is put on the SCTP stack with its {@code event} parameter set
     * to {@link AssociationChangeNotification.AssocChangeEvent#CANT_START CANT_START}.
     *
     * <P> The message is transferred from the byte buffer as if by a regular
     * {@link java.nio.channels.WritableByteChannel#write(java.nio.ByteBuffer)
     * write} operation.
     *
     * <P> If a security manager has been installed then for each new association
     * setup this method verifies that the given remote peers address and port
     * number are permitted by the security manager's {@link
     * java.lang.SecurityManager#checkConnect(String,int) checkConnect} method.
     *
     * <P> This method may be invoked at any time. If another thread has already
     * initiated a send operation upon this channel, then an invocation of
     * this method will block until the first operation is complete.
     *
     * @param  buffer
     *         The buffer containing the message to be sent
     *
     * @param  messageInfo
     *         Ancillary data about the message to be sent
     *
     * @return  The number of bytes sent, which will be either the number of
     *          bytes that were remaining in the messages buffer when this method
     *          was invoked or, if this channel is non-blocking, may be zero if
     *          there was insufficient room for the message in the underlying
     *          output buffer
     *
     * @throws  InvalidStreamExcepton
     *          If {@code streamNumber} is negative, or if an association already
     *          exists and {@code streamNumber} is greater than the maximum number
     *          of outgoing streams
     *
     * @throws  java.nio.channels.ClosedChannelException
     *          If this channel is closed
     *
     * @throws  java.nio.channels.AsynchronousCloseException
     *          If another thread closes this channel
     *          while the read operation is in progress
     *
     * @throws  java.nio.channels.ClosedByInterruptException
     *          If another thread interrupts the current thread
     *          while the read operation is in progress, thereby
     *          closing the channel and setting the current thread's
     *          interrupt status
     *
     * @throws  SecurityException
     *          If a security manager has been installed and it does not permit
     *          new associations to be setup with the the messages's address
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract int send(ByteBuffer buffer, MessageInfo messageInfo)
        throws IOException;

    
Branches off an association.

 An application can invoke this method to branch off an association into a separate channel. The new bound and connected SctpChannel will be created for the association. The branched off association will no longer be part of this channel. 
 This is particularly useful when, for instance, the application
wishes to have a number of sporadic message senders/receivers remain
under the original SCTP multi channel but branch off those
associations carrying high volume data traffic into their own
separate SCTP channels.

Params:
  • association – 
        The association to branch off
Throws:
Returns: The SctpChannel
/**
     * Branches off an association.
     *
     * <P> An application can invoke this method to branch off an association
     * into a separate channel. The new bound and connected {@link SctpChannel}
     * will be created for the association. The branched off association will no
     * longer be part of this channel.
     *
     * <P> This is particularly useful when, for instance, the application
     * wishes to have a number of sporadic message senders/receivers remain
     * under the original SCTP multi channel but branch off those
     * associations carrying high volume data traffic into their own
     * separate SCTP channels.
     *
     * @param  association
     *         The association to branch off
     *
     * @return  The {@code SctpChannel}
     *
     * @throws  java.nio.channels.ClosedChannelException
     *          If this channel is closed
     *
     * @throws  IOException
     *          If some other I/O error occurs
     */
    public abstract SctpChannel branch(Association association)
        throws IOException;
}