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}. * *
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}. * *
Socket options are configured using the * {@link #setOption(SctpSocketOption,Object,Association) setOption} method. An * {@code SctpMultiChannel} supports the following options: *
** Additional (implementation specific) options may also be supported. The list * of options supported is obtained by invoking the {@link #supportedOptions() * supportedOptions} method. * ** * *
** * * *Option Name *Description ** *{@link SctpStandardSocketOptions#SCTP_DISABLE_FRAGMENTS * SCTP_DISABLE_FRAGMENTS} *Enables or disables message fragmentation ** *{@link SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE * SCTP_EXPLICIT_COMPLETE} *Enables or disables explicit message completion ** *{@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE * SCTP_FRAGMENT_INTERLEAVE} *Controls how the presentation of messages occur for the message * receiver ** *{@link SctpStandardSocketOptions#SCTP_INIT_MAXSTREAMS * SCTP_INIT_MAXSTREAMS} *The maximum number of streams requested by the local endpoint during * association initialization ** *{@link SctpStandardSocketOptions#SCTP_NODELAY SCTP_NODELAY} *Enables or disable a Nagle-like algorithm ** *{@link SctpStandardSocketOptions#SCTP_PRIMARY_ADDR * SCTP_PRIMARY_ADDR} *Requests that the local SCTP stack use the given peer address as the * association primary ** *{@link SctpStandardSocketOptions#SCTP_SET_PEER_PRIMARY_ADDR * SCTP_SET_PEER_PRIMARY_ADDR} *Requests that the peer mark the enclosed address as the association * primary ** *{@link SctpStandardSocketOptions#SO_SNDBUF * SO_SNDBUF} *The size of the socket send buffer ** *{@link SctpStandardSocketOptions#SO_RCVBUF * SO_RCVBUF} *The size of the socket receive buffer ** * *{@link SctpStandardSocketOptions#SO_LINGER * SO_LINGER} *Linger on close if data is present (when configured in blocking mode * only) *
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. * * @param provider * The selector provider for this channel */ protected SctpMultiChannel(SelectorProvider provider) { super(provider); } /** * Opens an SCTP multi channel. * *
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.sctp.SctpMultiChannelImpl((SelectorProvider)null); } /** * Returns the open associations on this channel's socket. * *
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. * *
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 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.
*
* 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}.
*
* 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 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:
* 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.
*
* 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 {@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.
*
* 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}.
*
* 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.
*
* 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.
*
* @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 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 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 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 SCTP multi channels support reading, and writing, so this
* method returns
* {@code (}{@link SelectionKey#OP_READ} {@code |} {@link
* SelectionKey#OP_WRITE}{@code )}. 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}.
*
* 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.
*
* 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.
*
* 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.
*
* 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 If this channel is unbound then this method will invoke {@link
* #bind(SocketAddress, int) 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
* {@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}.
*
* 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.
*
* 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}.
*
* The message is transferred from the byte buffer as if by a regular
* {@link java.nio.channels.WritableByteChannel#write(java.nio.ByteBuffer)
* 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 {@link
* java.lang.SecurityManager#checkConnect(String,int) 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.
*
* @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 InvalidStreamException
* 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 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 {@link 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.
*
* @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;
}
*
* @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.
*
*
* bind(local, 0);
*