1 /*
2 * Copyright (c) 2009, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package com.sun.nio.sctp;
26
27 import java.net.SocketAddress;
28 import java.net.InetAddress;
29 import java.io.IOException;
30 import java.util.Set;
31 import java.nio.ByteBuffer;
32 import java.nio.channels.spi.AbstractSelectableChannel;
33 import java.nio.channels.spi.SelectorProvider;
34 import java.nio.channels.ClosedChannelException;
35 import java.nio.channels.SelectionKey;
36
37 /**
38 * A selectable channel for message-oriented connected SCTP sockets.
39 *
40 * <P> An SCTP channel can only control one SCTP association.
41 * An {@code SCTPChannel} is created by invoking one of the
42 * {@link #open open} methods of this class. A newly-created channel is open but
43 * not yet connected, that is, there is no association setup with a remote peer.
44 * An attempt to invoke an I/O operation upon an unconnected
45 * channel will cause a {@link java.nio.channels.NotYetConnectedException} to be
46 * thrown. An association can be setup by connecting the channel using one of
47 * its {@link #connect connect} methods. Once connected, the channel remains
48 * connected until it is closed. Whether or not a channel is connected may be
49 * determined by invoking {@link #getRemoteAddresses getRemoteAddresses}.
50 *
51 * <p> SCTP channels support <i>non-blocking connection:</i> A
52 * channel may be created and the process of establishing the link to
53 * the remote socket may be initiated via the {@link #connect connect} method
54 * for later completion by the {@link #finishConnect finishConnect} method.
55 * Whether or not a connection operation is in progress may be determined by
56 * invoking the {@link #isConnectionPending isConnectionPending} method.
57 *
58 * <p> Socket options are configured using the
59 * {@link #setOption(SctpSocketOption,Object) setOption} method. An SCTP
60 * channel support the following options:
61 * <blockquote>
62 * <table border>
63 * <tr>
64 * <th>Option Name</th>
65 * <th>Description</th>
66 * </tr>
67 * <tr>
68 * <td> {@link SctpStandardSocketOptions#SCTP_DISABLE_FRAGMENTS
69 * SCTP_DISABLE_FRAGMENTS} </td>
70 * <td> Enables or disables message fragmentation </td>
71 * </tr>
72 * <tr>
73 * <td> {@link SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE
74 * SCTP_EXPLICIT_COMPLETE} </td>
75 * <td> Enables or disables explicit message completion </td>
76 * </tr>
77 * <tr>
78 * <td> {@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE
79 * SCTP_FRAGMENT_INTERLEAVE} </td>
80 * <td> Controls how the presentation of messages occur for the message
81 * receiver </td>
82 * </tr>
83 * <tr>
84 * <td> {@link SctpStandardSocketOptions#SCTP_INIT_MAXSTREAMS
85 * SCTP_INIT_MAXSTREAMS} </td>
86 * <td> The maximum number of streams requested by the local endpoint during
87 * association initialization </td>
88 * </tr>
89 * <tr>
90 * <td> {@link SctpStandardSocketOptions#SCTP_NODELAY SCTP_NODELAY} </td>
91 * <td> Enables or disable a Nagle-like algorithm </td>
92 * </tr>
93 * <tr>
94 * <td> {@link SctpStandardSocketOptions#SCTP_PRIMARY_ADDR
95 * SCTP_PRIMARY_ADDR} </td>
96 * <td> Requests that the local SCTP stack use the given peer address as the
97 * association primary </td>
98 * </tr>
99 * <tr>
100 * <td> {@link SctpStandardSocketOptions#SCTP_SET_PEER_PRIMARY_ADDR
101 * SCTP_SET_PEER_PRIMARY_ADDR} </td>
102 * <td> Requests that the peer mark the enclosed address as the association
103 * primary </td>
104 * </tr>
105 * <tr>
106 * <td> {@link SctpStandardSocketOptions#SO_SNDBUF
107 * SO_SNDBUF} </td>
108 * <td> The size of the socket send buffer </td>
109 * </tr>
110 * <tr>
111 * <td> {@link SctpStandardSocketOptions#SO_RCVBUF
112 * SO_RCVBUF} </td>
113 * <td> The size of the socket receive buffer </td>
114 * </tr>
115 * <tr>
116 * <td> {@link SctpStandardSocketOptions#SO_LINGER
117 * SO_LINGER} </td>
118 * <td> Linger on close if data is present (when configured in blocking mode
119 * only) </td>
120 * </tr>
121 * </table>
122 * </blockquote>
123 * Additional (implementation specific) options may also be supported. The list
124 * of options supported is obtained by invoking the {@link #supportedOptions()
125 * supportedOptions} method.
126 *
127 * <p> SCTP channels are safe for use by multiple concurrent threads.
128 * They support concurrent reading and writing, though at most one thread may be
129 * reading and at most one thread may be writing at any given time. The
130 * {@link #connect connect} and {@link #finishConnect
131 * finishConnect} methods are mutually synchronized against each other, and
132 * an attempt to initiate a send or receive operation while an invocation of one
133 * of these methods is in progress will block until that invocation is complete.
134 *
135 * @since 1.7
136 */
137 public abstract class SctpChannel
138 extends AbstractSelectableChannel
139 {
140 /**
141 * Initializes a new instance of this class.
142 *
143 * @param provider
144 * The selector provider for this channel
145 */
146 protected SctpChannel(SelectorProvider provider) {
147 super(provider);
148 }
149
150 /**
151 * Opens an SCTP channel.
152 *
153 * <P> The new channel is unbound and unconnected.
154 *
155 * @return A new SCTP channel
156 *
157 * @throws UnsupportedOperationException
158 * If the SCTP protocol is not supported
159 *
160 * @throws IOException
161 * If an I/O error occurs
162 */
163 public static SctpChannel open() throws
164 IOException {
165 return new sun.nio.ch.sctp.SctpChannelImpl((SelectorProvider)null);
166 }
167
168 /**
169 * Opens an SCTP channel and connects it to a remote address.
170 *
171 * <P> This is a convenience method and is equivalent to evaluating the
172 * following expression:
173 * <blockquote><pre>
174 * open().connect(remote, maxOutStreams, maxInStreams);
175 * </pre></blockquote>
176 *
177 * @param remote
178 * The remote address to which the new channel is to be connected
179 *
180 * @param maxOutStreams
181 * The number of streams that the application wishes to be able
182 * to send to. Must be non negative and no larger than {@code 65536}.
183 * {@code 0} to use the endpoints default value.
184 *
185 * @param maxInStreams
186 * The maximum number of inbound streams the application is prepared
187 * to support. Must be non negative and no larger than {@code 65536}.
188 * {@code 0} to use the endpoints default value.
189 *
190 * @return A new SCTP channel connected to the given address
191 *
192 * @throws java.nio.channels.AsynchronousCloseException
193 * If another thread closes this channel
194 * while the connect operation is in progress
195 *
196 * @throws java.nio.channels.ClosedByInterruptException
197 * If another thread interrupts the current thread
198 * while the connect operation is in progress, thereby
199 * closing the channel and setting the current thread's
200 * interrupt status
201 *
202 * @throws java.nio.channels.UnresolvedAddressException
203 * If the given remote address is not fully resolved
204 *
205 * @throws java.nio.channels.UnsupportedAddressTypeException
206 * If the type of the given remote address is not supported
207 *
208 * @throws SecurityException
209 * If a security manager has been installed
210 * and it does not permit access to the given remote peer
211 *
212 * @throws UnsupportedOperationException
213 * If the SCTP protocol is not supported
214 *
215 * @throws IOException
216 * If some other I/O error occurs
217 */
218 public static SctpChannel open(SocketAddress remote, int maxOutStreams,
219 int maxInStreams) throws IOException {
220 SctpChannel ssc = SctpChannel.open();
221 ssc.connect(remote, maxOutStreams, maxInStreams);
222 return ssc;
223 }
224
225 /**
226 * Returns the association on this channel's socket.
227 *
228 * @return the association, or {@code null} if the channel's socket is not
229 * connected.
230 *
231 * @throws ClosedChannelException
232 * If the channel is closed
233 *
234 * @throws IOException
235 * If some other I/O error occurs
236 */
237 public abstract Association association() throws IOException;
238
239 /**
240 * Binds the channel's socket to a local address.
241 *
242 * <P> This method is used to establish a relationship between the socket
243 * and the local addresses. Once a relationship is established then
244 * the socket remains bound until the channel is closed. This relationship
245 * may not necesssarily be with the address {@code local} as it may be removed
246 * by {@link #unbindAddress unbindAddress}, but there will always be at least
247 * one local address bound to the channel's socket once an invocation of
248 * this method successfully completes.
249 *
250 * <P> Once the channel's socket has been successfully bound to a specific
251 * address, that is not automatically assigned, more addresses
252 * may be bound to it using {@link #bindAddress bindAddress}, or removed
253 * using {@link #unbindAddress unbindAddress}.
254 *
255 * @param local
256 * The local address to bind the socket, or {@code null} to
257 * bind the socket to an automatically assigned socket address
258 *
259 * @return This channel
260 *
261 * @throws java.nio.channels.AlreadyConnectedException
262 * If this channel is already connected
263 *
264 * @throws java.nio.channels.ClosedChannelException
265 * If this channel is closed
266 *
267 * @throws java.nio.channels.ConnectionPendingException
268 * If a non-blocking connection operation is already in progress on this channel
269 *
270 * @throws java.nio.channels.AlreadyBoundException
271 * If this channel is already bound
272 *
273 * @throws java.nio.channels.UnsupportedAddressTypeException
274 * If the type of the given address is not supported
275 *
276 * @throws IOException
277 * If some other I/O error occurs
278 */
279 public abstract SctpChannel bind(SocketAddress local)
280 throws IOException;
281
282 /**
283 * Adds the given address to the bound addresses for the channel's
284 * socket.
285 *
286 * <P> The given address must not be the {@link
287 * java.net.InetAddress#isAnyLocalAddress wildcard} address.
288 * The channel must be first bound using {@link #bind bind} before
289 * invoking this method, otherwise {@link
290 * java.nio.channels.NotYetBoundException} is thrown. The {@link #bind bind}
291 * method takes a {@code SocketAddress} as its argument which typically
292 * contains a port number as well as an address. Addresses subquently bound
293 * using this method are simply addresses as the SCTP port number remains
294 * the same for the lifetime of the channel.
295 *
296 * <P> Adding addresses to a connected association is optional functionality.
297 * If the endpoint supports dynamic address reconfiguration then it may
298 * send the appropriate message to the peer to change the peers address
299 * lists.
300 *
301 * @param address
302 * The address to add to the bound addresses for the socket
303 *
304 * @return This channel
305 *
306 * @throws java.nio.channels.ClosedChannelException
307 * If this channel is closed
308 *
309 * @throws java.nio.channels.ConnectionPendingException
310 * If a non-blocking connection operation is already in progress on
311 * this channel
312 *
313 * @throws java.nio.channels.NotYetBoundException
314 * If this channel is not yet bound
315 *
316 * @throws java.nio.channels.AlreadyBoundException
317 * If this channel is already bound to the given address
318 *
319 * @throws IllegalArgumentException
320 * If address is {@code null} or the {@link
321 * java.net.InetAddress#isAnyLocalAddress wildcard} address
322 *
323 * @throws IOException
324 * If some other I/O error occurs
325 */
326 public abstract SctpChannel bindAddress(InetAddress address)
327 throws IOException;
328
329 /**
330 * Removes the given address from the bound addresses for the channel's
331 * socket.
332 *
333 * <P> The given address must not be the {@link
334 * java.net.InetAddress#isAnyLocalAddress wildcard} address.
335 * The channel must be first bound using {@link #bind bind} before
336 * invoking this method, otherwise {@link java.nio.channels.NotYetBoundException}
337 * is thrown. If this method is invoked on a channel that does not have
338 * {@code address} as one of its bound addresses or that has only one
339 * local address bound to it, then this method throws
340 * {@link IllegalUnbindException}.
341 * The initial address that the channel's socket is bound to using {@link
342 * #bind bind} may be removed from the bound addresses for the channel's socket.
343 *
344 * <P> Removing addresses from a connected association is optional
345 * functionality. If the endpoint supports dynamic address reconfiguration
346 * then it may send the appropriate message to the peer to change the peers
347 * address lists.
348 *
349 * @param address
350 * The address to remove from the bound addresses for the socket
351 *
352 * @return This channel
353 *
354 * @throws java.nio.channels.ClosedChannelException
355 * If this channel is closed
356 *
357 * @throws java.nio.channels.ConnectionPendingException
358 * If a non-blocking connection operation is already in progress on
359 * this channel
360 *
361 * @throws java.nio.channels.NotYetBoundException
362 * If this channel is not yet bound
363 *
364 * @throws IllegalArgumentException
365 * If address is {@code null} or the {@link
366 * java.net.InetAddress#isAnyLocalAddress wildcard} address
367 *
368 * @throws IllegalUnbindException
369 * If {@code address} is not bound to the channel's socket. or
370 * the channel has only one address bound to it
371 *
372 * @throws IOException
373 * If some other I/O error occurs
374 */
375 public abstract SctpChannel unbindAddress(InetAddress address)
376 throws IOException;
377
378 /**
379 * Connects this channel's socket.
380 *
381 * <P> If this channel is in non-blocking mode then an invocation of this
382 * method initiates a non-blocking connection operation. If the connection
383 * is established immediately, as can happen with a local connection, then
384 * this method returns {@code true}. Otherwise this method returns
385 * {@code false} and the connection operation must later be completed by
386 * invoking the {@link #finishConnect finishConnect} method.
387 *
388 * <P> If this channel is in blocking mode then an invocation of this
389 * method will block until the connection is established or an I/O error
390 * occurs.
391 *
392 * <P> If a security manager has been installed then this method verifies
393 * that its {@link java.lang.SecurityManager#checkConnect checkConnect}
394 * method permits connecting to the address and port number of the given
395 * remote peer.
396 *
397 * <p> This method may be invoked at any time. If a {@link #send send} or
398 * {@link #receive receive} operation upon this channel is invoked while an
399 * invocation of this method is in progress then that operation will first
400 * block until this invocation is complete. If a connection attempt is
401 * initiated but fails, that is, if an invocation of this method throws a
402 * checked exception, then the channel will be closed.
403 *
404 * @param remote
405 * The remote peer to which this channel is to be connected
406 *
407 * @return {@code true} if a connection was established, {@code false} if
408 * this channel is in non-blocking mode and the connection
409 * operation is in progress
410 *
411 * @throws java.nio.channels.AlreadyConnectedException
412 * If this channel is already connected
413 *
414 * @throws java.nio.channels.ConnectionPendingException
415 * If a non-blocking connection operation is already in progress on
416 * this channel
417 *
418 * @throws java.nio.channels.ClosedChannelException
419 * If this channel is closed
420 *
421 * @throws java.nio.channels.AsynchronousCloseException
422 * If another thread closes this channel
423 * while the connect operation is in progress
424 *
425 * @throws java.nio.channels.ClosedByInterruptException
426 * If another thread interrupts the current thread
427 * while the connect operation is in progress, thereby
428 * closing the channel and setting the current thread's
429 * interrupt status
430 *
431 * @throws java.nio.channels.UnresolvedAddressException
432 * If the given remote address is not fully resolved
433 *
434 * @throws java.nio.channels.UnsupportedAddressTypeException
435 * If the type of the given remote address is not supported
436 *
437 * @throws SecurityException
438 * If a security manager has been installed
439 * and it does not permit access to the given remote peer
440 *
441 * @throws IOException
442 * If some other I/O error occurs
443 */
444 public abstract boolean connect(SocketAddress remote) throws IOException;
445
446 /**
447 * Connects this channel's socket.
448 *
449 * <P> This is a convience method and is equivalent to evaluating the
450 * following expression:
451 * <blockquote><pre>
452 * setOption(SctpStandardSocketOptions.SCTP_INIT_MAXSTREAMS, SctpStandardSocketOption.InitMaxStreams.create(maxInStreams, maxOutStreams))
453 * .connect(remote);
454 * </pre></blockquote>
455 *
456 * <P> The {@code maxOutStreams} and {@code maxInStreams} parameters
457 * represent the maximum number of streams that the application wishes to be
458 * able to send to and receive from. They are negotiated with the remote
459 * peer and may be limited by the operating system.
460 *
461 * @param remote
462 * The remote peer to which this channel is to be connected
463 *
464 * @param maxOutStreams
465 * Must be non negative and no larger than {@code 65536}.
466 * {@code 0} to use the endpoints default value.
467 *
468 * @param maxInStreams
469 * Must be non negative and no larger than {@code 65536}.
470 * {@code 0} to use the endpoints default value.
471 *
472 * @return {@code true} if a connection was established, {@code false} if
473 * this channel is in non-blocking mode and the connection operation
474 * is in progress
475 *
476 * @throws java.nio.channels.AlreadyConnectedException
477 * If this channel is already connected
478 *
479 * @throws java.nio.channels.ConnectionPendingException
480 * If a non-blocking connection operation is already in progress on
481 * this channel
482 *
483 * @throws java.nio.channels.ClosedChannelException
484 * If this channel is closed
485 *
486 * @throws java.nio.channels.AsynchronousCloseException
487 * If another thread closes this channel
488 * while the connect operation is in progress
489 *
490 * @throws java.nio.channels.ClosedByInterruptException
491 * If another thread interrupts the current thread
492 * while the connect operation is in progress, thereby
493 * closing the channel and setting the current thread's
494 * interrupt status
495 *
496 * @throws java.nio.channels.UnresolvedAddressException
497 * If the given remote address is not fully resolved
498 *
499 * @throws java.nio.channels.UnsupportedAddressTypeException
500 * If the type of the given remote address is not supported
501 *
502 * @throws SecurityException
503 * If a security manager has been installed
504 * and it does not permit access to the given remote peer
505 *
506 * @throws IOException
507 * If some other I/O error occurs
508 */
509 public abstract boolean connect(SocketAddress remote,
510 int maxOutStreams,
511 int maxInStreams)
512 throws IOException;
513
514 /**
515 * Tells whether or not a connection operation is in progress on this channel.
516 *
517 * @return {@code true} if, and only if, a connection operation has been initiated
518 * on this channel but not yet completed by invoking the
519 * {@link #finishConnect} method
520 */
521 public abstract boolean isConnectionPending();
522
523 /**
524 * Finishes the process of connecting an SCTP channel.
525 *
526 * <P> A non-blocking connection operation is initiated by placing a socket
527 * channel in non-blocking mode and then invoking one of its {@link #connect
528 * connect} methods. Once the connection is established, or the attempt has
529 * failed, the channel will become connectable and this method may
530 * be invoked to complete the connection sequence. If the connection
531 * operation failed then invoking this method will cause an appropriate
532 * {@link java.io.IOException} to be thrown.
533 *
534 * <P> If this channel is already connected then this method will not block
535 * and will immediately return <tt>true</tt>. If this channel is in
536 * non-blocking mode then this method will return <tt>false</tt> if the
537 * connection process is not yet complete. If this channel is in blocking
538 * mode then this method will block until the connection either completes
539 * or fails, and will always either return <tt>true</tt> or throw a checked
540 * exception describing the failure.
541 *
542 * <P> This method may be invoked at any time. If a {@link #send send} or {@link #receive receive}
543 * operation upon this channel is invoked while an invocation of this
544 * method is in progress then that operation will first block until this
545 * invocation is complete. If a connection attempt fails, that is, if an
546 * invocation of this method throws a checked exception, then the channel
547 * will be closed.
548 *
549 * @return {@code true} if, and only if, this channel's socket is now
550 * connected
551 *
552 * @throws java.nio.channels.NoConnectionPendingException
553 * If this channel is not connected and a connection operation
554 * has not been initiated
555 *
556 * @throws java.nio.channels.ClosedChannelException
557 * If this channel is closed
558 *
559 * @throws java.nio.channels.AsynchronousCloseException
560 * If another thread closes this channel
561 * while the connect operation is in progress
562 *
563 * @throws java.nio.channels.ClosedByInterruptException
564 * If another thread interrupts the current thread
565 * while the connect operation is in progress, thereby
566 * closing the channel and setting the current thread's
567 * interrupt status
568 *
569 * @throws IOException
570 * If some other I/O error occurs
571 */
572 public abstract boolean finishConnect() throws IOException;
573
574 /**
575 * Returns all of the socket addresses to which this channel's socket is
576 * bound.
577 *
578 * @return All the socket addresses that this channel's socket is
579 * bound to, or an empty {@code Set} if the channel's socket is not
580 * bound
581 *
582 * @throws ClosedChannelException
583 * If the channel is closed
584 *
585 * @throws IOException
586 * If an I/O error occurs
587 */
588 public abstract Set<SocketAddress> getAllLocalAddresses()
589 throws IOException;
590
591 /**
592 * Returns all of the remote addresses to which this channel's socket
593 * is connected.
594 *
595 * <P> If the channel is connected to a remote peer that is bound to
596 * multiple addresses then it is these addresses that the channel's socket
597 * is connected.
598 *
599 * @return All of the remote addresses to which this channel's socket
600 * is connected, or an empty {@code Set} if the channel's socket is
601 * not connected
602 *
603 * @throws ClosedChannelException
604 * If the channel is closed
605 *
606 * @throws IOException
607 * If an I/O error occurs
608 */
609 public abstract Set<SocketAddress> getRemoteAddresses()
610 throws IOException;
611
612 /**
613 * Shutdown a connection without closing the channel.
614 *
615 * <P> Sends a shutdown command to the remote peer, effectively preventing
616 * any new data from being written to the socket by either peer. Further
617 * sends will throw {@link java.nio.channels.ClosedChannelException}. The
618 * channel remains open to allow the for any data (and notifications) to be
619 * received that may have been sent by the peer before it received the
620 * shutdown command. If the channel is already shutdown then invoking this
621 * method has no effect.
622 *
623 * @return This channel
624 *
625 * @throws java.nio.channels.NotYetConnectedException
626 * If this channel is not yet connected
627 *
628 * @throws java.nio.channels.ClosedChannelException
629 * If this channel is closed
630 *
631 * @throws IOException
632 * If some other I/O error occurs
633 */
634 public abstract SctpChannel shutdown() throws IOException;
635
636 /**
637 * Returns the value of a socket option.
638 *
639 * @param name
640 * The socket option
641 *
642 * @return The value of the socket option. A value of {@code null} may be
643 * a valid value for some socket options.
644 *
645 * @throws UnsupportedOperationException
646 * If the socket option is not supported by this channel
647 *
648 * @throws ClosedChannelException
649 * If this channel is closed
650 *
651 * @throws IOException
652 * If an I/O error occurs
653 *
654 * @see SctpStandardSocketOptions
655 */
656 public abstract <T> T getOption(SctpSocketOption<T> name)
657 throws IOException;
658
659 /**
660 * Sets the value of a socket option.
661 *
662 * @param name
663 * The socket option
664 *
665 * @param value
666 * The value of the socket option. A value of {@code null} may be
667 * a valid value for some socket options.
668 *
669 * @return This channel
670 *
671 * @throws UnsupportedOperationException
672 * If the socket option is not supported by this channel
673 *
674 * @throws IllegalArgumentException
675 * If the value is not a valid value for this socket option
676 *
677 * @throws ClosedChannelException
678 * If this channel is closed
679 *
680 * @throws IOException
681 * If an I/O error occurs
682 *
683 * @see SctpStandardSocketOptions
684 */
685 public abstract <T> SctpChannel setOption(SctpSocketOption<T> name, T value)
686 throws IOException;
687
688 /**
689 * Returns a set of the socket options supported by this channel.
690 *
691 * <P> This method will continue to return the set of options even after the
692 * channel has been closed.
693 *
694 * @return A set of the socket options supported by this channel
695 */
696 public abstract Set<SctpSocketOption<?>> supportedOptions();
697
698 /**
699 * Returns an operation set identifying this channel's supported operations.
700 *
701 * <P> SCTP channels support connecting, reading, and writing, so this
702 * method returns <tt>(</tt>{@link SelectionKey#OP_CONNECT}
703 * <tt>|</tt> {@link SelectionKey#OP_READ} <tt>|</tt> {@link
704 * SelectionKey#OP_WRITE}<tt>)</tt>. </p>
705 *
706 * @return The valid-operation set
707 */
708 @Override
709 public final int validOps() {
710 return (SelectionKey.OP_READ |
711 SelectionKey.OP_WRITE |
712 SelectionKey.OP_CONNECT);
713 }
714
715 /**
716 * Receives a message into the given buffer and/or handles a notification.
717 *
718 * <P> If a message or notification is immediately available, or if this
719 * channel is in blocking mode and one eventually becomes available, then
720 * the message or notification is returned or handled, respectively. If this
721 * channel is in non-blocking mode and a message or notification is not
722 * immediately available then this method immediately returns {@code null}.
723 *
724 * <P> If this method receives a message it is copied into the given byte
725 * buffer. The message is transferred into the given byte buffer starting at
726 * its current position and the buffers position is incremented by the
727 * number of bytes read. If there are fewer bytes remaining in the buffer
728 * than are required to hold the message, or the underlying input buffer
729 * does not contain the complete message, then an invocation of {@link
730 * MessageInfo#isComplete isComplete} on the returned {@code
731 * MessageInfo} will return {@code false}, and more invocations of this
732 * method will be necessary to completely consume the messgae. Only
733 * one message at a time will be partially delivered in any stream. The
734 * socket option {@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE
735 * SCTP_FRAGMENT_INTERLEAVE} controls various aspects of what interlacing of
736 * messages occurs.
737 *
738 * <P> If this method receives a notification then the appropriate method of
739 * the given handler, if there is one, is invoked. If the handler returns
740 * {@link HandlerResult#CONTINUE CONTINUE} then this method will try to
741 * receive another message/notification, otherwise, if {@link
742 * HandlerResult#RETURN RETURN} is returned this method will return {@code
743 * null}. If an uncaught exception is thrown by the handler it will be
744 * propagated up the stack through this method.
745 *
746 * <P> This method may be invoked at any time. If another thread has
747 * already initiated a receive operation upon this channel, then an
748 * invocation of this method will block until the first operation is
749 * complete. The given handler is invoked without holding any locks used
750 * to enforce the above synchronization policy, that way handlers
751 * will not stall other threads from receiving. A handler should not invoke
752 * the {@code receive} method of this channel, if it does an
753 * {@link IllegalReceiveException} will be thrown.
754 *
755 * @param dst
756 * The buffer into which message bytes are to be transferred
757 *
758 * @param attachment
759 * The object to attach to the receive operation; can be
760 * {@code null}
761 *
762 * @param handler
763 * A handler to handle notifications from the SCTP stack, or {@code
764 * null} to ignore any notifications.
765 *
766 * @return The {@code MessageInfo}, {@code null} if this channel is in
767 * non-blocking mode and no messages are immediately available or
768 * the notification handler returns {@link HandlerResult#RETURN
769 * RETURN} after handling a notification
770 *
771 * @throws java.nio.channels.ClosedChannelException
772 * If this channel is closed
773 *
774 * @throws java.nio.channels.AsynchronousCloseException
775 * If another thread closes this channel
776 * while the read operation is in progress
777 *
778 * @throws java.nio.channels.ClosedByInterruptException
779 * If another thread interrupts the current thread
780 * while the read operation is in progress, thereby
781 * closing the channel and setting the current thread's
782 * interrupt status
783 *
784 * @throws java.nio.channels.NotYetConnectedException
785 * If this channel is not yet connected
786 *
787 * @throws IllegalReceiveException
788 * If the given handler invokes the {@code receive} method of this
789 * channel
790 *
791 * @throws IOException
792 * If some other I/O error occurs
793 */
794 public abstract <T> MessageInfo receive(ByteBuffer dst,
795 T attachment,
796 NotificationHandler<T> handler)
797 throws IOException;
798
799 /**
800 * Sends a message via this channel.
801 *
802 * <P> If this channel is in non-blocking mode and there is sufficient room
803 * in the underlying output buffer, or if this channel is in blocking mode
804 * and sufficient room becomes available, then the remaining bytes in the
805 * given byte buffer are transmitted as a single message. Sending a message
806 * is atomic unless explicit message completion {@link
807 * SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE SCTP_EXPLICIT_COMPLETE}
808 * socket option is enabled on this channel's socket.
809 *
810 * <P> The message is transferred from the byte buffer as if by a regular
811 * {@link java.nio.channels.WritableByteChannel#write(java.nio.ByteBuffer)
812 * write} operation.
813 *
814 * <P> The bytes will be written to the stream number that is specified by
815 * {@link MessageInfo#streamNumber streamNumber} in the given {@code
816 * messageInfo}.
817 *
818 * <P> This method may be invoked at any time. If another thread has already
819 * initiated a send operation upon this channel, then an invocation of
820 * this method will block until the first operation is complete.
821 *
822 * @param src
823 * The buffer containing the message to be sent
824 *
825 * @param messageInfo
826 * Ancillary data about the message to be sent
827 *
828 * @return The number of bytes sent, which will be either the number of
829 * bytes that were remaining in the messages buffer when this method
830 * was invoked or, if this channel is non-blocking, may be zero if
831 * there was insufficient room for the message in the underlying
832 * output buffer
833 *
834 * @throws InvalidStreamExcepton
835 * If {@code streamNumner} is negative or greater than or equal to
836 * the maximum number of outgoing streams
837 *
838 * @throws java.nio.channels.ClosedChannelException
839 * If this channel is closed
840 *
841 * @throws java.nio.channels.AsynchronousCloseException
842 * If another thread closes this channel
843 * while the read operation is in progress
844 *
845 * @throws java.nio.channels.ClosedByInterruptException
846 * If another thread interrupts the current thread
847 * while the read operation is in progress, thereby
848 * closing the channel and setting the current thread's
849 * interrupt status
850 *
851 * @throws java.nio.channels.NotYetConnectedException
852 * If this channel is not yet connected
853 *
854 * @throws IOException
855 * If some other I/O error occurs
856 */
857 public abstract int send(ByteBuffer src, MessageInfo messageInfo)
858 throws IOException;
859 }