1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
|
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<title>Real-Time Event Channel Configuration</title>
<!-- $Id$-->
</head>
<body>
<CENTER>
<h1>Real-Time Event Channel Configuration</h1>
</CENTER>
<H3>Configuring the Event Channel at Compilation Time</H3>
<P>TAO's Real-Time Event Channel can be configured at compilation
time to use a different payload than its default. To do so
there are several options:
</P>
<UL>
<LI><P>To eliminate the <CODE>CORBA::Any</CODE> field in the
event payload you should define the
<CODE>TAO_LACKS_EVENT_CHANNEL_ANY</CODE>
macro when invoking the IDL compiler.
You can do as follows:
<PRE>
$ cd $TAO_ROOT/orbsvcs/orbsvcs
$ make TAO_IDLFLAGS=-DTAO_LACKS_EVENT_CHANNEL_ANY
</PRE>
</P>
</LI>
<LI><P>Similarly you can eliminate the octet sequence field in
the event payload using:
<PRE>
$ cd $TAO_ROOT/orbsvcs/orbsvcs
$ make TAO_IDLFLAGS=-DTAO_LACKS_EVENT_CHANNEL_OCTET_SEQUENCE
</PRE>
</P>
</LI>
<LI><P>Finally you can provide your own event payload, to do
this you should Replace the contents of the
<CODE>RtecDefaultEventData.idl</CODE>
and define some IDL structure named
<CODE>RtecEventData</CODE>.
For example, you could define you own event type as follows:
<PRE>
// Replace RtecDefaultEventData.idl with this:
struct RtecEventData
{
sequence<long> my_event_payload;
};
</PRE>
</LI>
</UL>
<H3>Run-time Configuration</H3>
<P>The new implementation of the real-time event channel uses a
factory to build all the objects and strategies it requires.
The factory can be dynamically loaded using ACE Service
Configurator, this is extremely convenient because the factory
can also parse options in the Service Configurator script file.
</P>
<P>There are currently several implementations of the factory.
<ul>
<li>The <em>default</em> factory supports all of
the options below and most of the potential values, except as
specifically indicated.
<li>
The <em>sched</em> factory defines new option values as indicated
below that allow the RTES to integrate with the Real-Time
Scheduling Service. Use of the <em>sched</em> factory requires
that you link in the TAO_RTSchedEvent library.
<li>
The <em>tpc</em> (thread per consumer) factory defines new
options values as indicated below. This
strategy is similar to the MT dispatching strategy in that it
separates the thread that receives the push() from a supplier
from the thread that does the eventual push() to the
consumer(s), but it differs from MT in that MT has a pool of
threads pulling from a single queue and ultimately potentially
servicing every consumer, whereas TPC has a queue for <em>each</em>
consumer and, thus, a single thread dedicated to pushing to that
consumer. This insures that a badly-behaved consumer <b>CANNOT</b>
have an adverse effect on the channel or supplier.<br>
To use this new strategy you will have to replace the call in your code
for <code>TAO_EC_Default_Factory::init_svcs()</code> with
<code>TAO_EC_TPC_Factory::init_svcs()</code>.
<li> The <em>basic</em> and <em>null</em> factories are hard-coded
factories that do not support any configuration options.
They both define simple configurations that may enable some
applications to use the RTES in a smaller footprint.
See the files
<code>$TAO_ROOT/orbsvcs/orbsvcs/Event/EC_Null_Factory.h</code>
and <code>$TAO_ROOT/orbsvcs/orbsvcs/Event/EC_Basic_Factory.h</code>
for details.
</ul>
The
table below describes all of the options (and values) supported by
these factories.
</P>
<h3>Special Topic: Queue Configuration</h3>
<p>
In certain configurations such as <em>mt</em> and <em>tpc</em>,
the RTES implementation uses something called
<code>TAO_EC_Queue</code>, which is an in-memory queue that
separates threads that receive <code>push()</code> invocations
from suppliers from the threads that dispatch
<code>push()</code> invocations to consumers. A user of the
RTES can configure some behaviors of this queue as well as
behaviors when the queue reaches certain trigger points. The
configuration of these behaviors is a combination of
compile-time and run-time specification.
</p>
<p>
The queue itself has two trigger points for the number of
invocations in the queue:
<ul>
<li><em>low-water mark (LWM)</em>, a lower threshold below which the
queue allows more invocations to be placed into the queue;
<li><em>high-water mark (HWM)</em>, an upper threshold above which the
queue prevents more invocations from being added to the queue
</ul>
The values for these can be set at compile time via
<code>TAO_EC_QUEUE_LWM</code> and <code>TAO_EC_QUEUE_HWM</code>
for the low-water mark and high-water mark, respectively.
<p>
In addition, an application can specify what the RTES should do if a
queue reaches the HWM, i.e., fills up. This behavior is encapsulated in a
derivation of an <code>ACE_Service_Object</code>, called
<code>TAO_EC_Queue_Full_Service_Object</code>. The RTES looks
for a service object of a particular name (the default for this
name is in macro TAO_EC_DEFAULT_QUEUE_FULL_SERVICE_OBJECT_NAME,
which is "EC_QueueFullSimpleActions") and invokes
<code>queue_full_action()</code> on the instance. See class
<code>TAO_EC_Simple_Queue_Full_Action</code> in file
<code>$TAO_ROOT/orbsvcs/orbsvcs/Event/EC_Dispatching_Task.h</code>
for an example. This particular example can be configured to
either <em>wait</em> or <em>discard</em> new invocations on
reaching the HWM.
</p>
<H3>The configuration file</H3>
<P>The real-time event channel uses the same service configurator
file that the ORB uses, the default name for this file is
<CODE>svc.conf</CODE>, but the ORB option
<CODE>-ORBSvcConf</CODE> can be used to override this.
The format of the file is described in detail in
the service configurator documentation, but the relevant section
for the event channel looks like this:
</P>
<PRE>
# Comments go here...
# More comments if you want to...
static EC_Factory "-ECFiltering basic ....."
# ...and optionally...
static EC_QueueFullSimpleActions "[wait | discard]"
# ...or you can define your own TAO_EC_Queue_Full_Service_Object,
# give it whatever name you want and use -ECQueueFullServiceObject
# (see below) to specify that object's service configurator tag.
</PRE>
<P>All the event service factory options start with
<CODE>-EC</CODE></P>
<H3>The options</H3>
<P><TABLE BORDER="2" CELLSPACING="2" CELLPADDING="0">
<TR>
<TH>Option</TH>
<TH>Description</TH>
</TR>
<!-- <TR NAME="ECDispatching"> -->
<TR>
<TD><CODE>-ECDispatching</CODE>
<EM>dispatching_strategy</EM>
</TD>
<TD>Select the dispatching strategy used by the real-time
event service. The <EM>reactive</EM> strategy uses the
same thread that received the event from the supplier to
push the event to all the consumers.<br>
The <EM>priority</EM> strategy (sched factory only) uses
a prioritized pool
of threads and queries the scheduling service to select
the thread that dispatches each event.<br>
The <EM>mt</EM> strategy also uses a pool of threads,
but the thread to dispatch is randomly selected.<br>
<b>Does not apply to the <em>tpc</em> factory.</b>
</TD>
</TR>
<!-- <TR NAME="ECDispatchingThreads"> -->
<TR>
<TD><CODE>-ECDispatchingThreads</CODE>
<EM>number_of_threads</EM>
</TD>
<TD>Select the number of threads used by the <EM>mt</EM>
dispatching strategy.<br>
<b>Does not apply to the <em>tpc</em> factory.</b>
</TD>
</TR>
<!-- <TR NAME="ECQueueFullServiceObject"> -->
<tr>
<td><code>-ECQueueFullServiceObject</code>
<em>service_object_name</em>
</td>
<td>
Used to specify the name/tag in the service configurator
through which the RTEC should look for a "queue full
service object".<br>
<b>Will only have an effect on dispatch strategies that
use <code>TAO_EC_Queue</code>.</b>
</td>
</tr>
<!-- <TR NAME="ECFiltering"> -->
<TR>
<TD><CODE>-ECFiltering</CODE>
<EM>consumer_filtering_strategy</EM>
</TD>
<TD>Select the filtering strategy used by the consumers.
The <EM>null</EM> filtering strategy will build trivial
filters for all consumers.
The <EM>basic</EM> filtering strategy supports
disjunction, conjunction, logical and, negation, bitmask,
and timeout filters based on the subscriptions passed by
the consumer during the connect call. It only supports limited
nesting of filter groups.
The <EM>prefix</EM> filtering strategy supports
all filter types that the <EM>basic</EM> strategy does
and allows unlimited nesting of filter groups.
When using the <EM>prefix</EM> strategy, the source field of the
group filter must specify the number of children in the group.
The <EM>priority</EM> filtering strategy (sched factory only)
supports the same
features as the <EM>basic</EM> filtering strategy, but it
also collaborates with the scheduling service to build the
dependency graph.
</TD>
</TR>
<!-- <TR NAME="ECSupplierFiltering"> -->
<TR>
<TD><CODE>-ECSupplierFiltering</CODE>
<EM>supplier_filtering_strategy</EM>
</TD>
<TD>The event channel can also perform some filtering close
to the suppliers by minimizing the number of consumers
that are tested for given event.
If the strategy is <EM>null</EM> then a global collection
of consumers is maintained and each event is filtered by
each consumer.
If the strategy is <EM>per-supplier</EM> then the EC uses
the supplier publications and the consumer subscriptions
to determine which consumers could potentially be
interested in events for each supplier.
This set of consumers is usually smaller than the complete
set and it is thus faster to traverse it, but keeping more
collections of consumers increases the connection and
disconnection time as well as the memory requirements.
</TD>
</TR>
<!-- <TR NAME="ECTimeout"> -->
<TR>
<TD><CODE>-ECTimeout</CODE>
<EM>timeout_strategy</EM>
</TD>
<TD>A consumer can request that the event channel generate
periodic or oneshot timeout events.
This option controls the strategy to generate the
timeouts,
using <EM>reactive</EM> the same reactor used for the ORB
is used by the event service.
The <EM>priority</EM> strategy (sched factory only) uses a
prioritized group of
threads, timeouts with higher rate are generated by
threads of higher priority.
<BR><B>NOTE: The <EM>priority</EM> strategy is not
implemented</B>
</TD>
</TR>
<!-- <TR NAME="ECObserver"> -->
<TR>
<TD><CODE>-ECObserver</CODE>
<EM>observer</EM>
</TD>
<TD>The event channel uses the Observer pattern to report
changes in the subscriptions and publications of its
suppliers and consumers; this is especially useful in the
implementation of event channel gateways.
The user can disable this feature by selecting the
<EM>null</EM> strategy;
whereas the <EM>basic</EM> strategy provides a simple, yet
efficient implementation. <EM>reactive</EM> provides a
strategy in which an observer that is unreachable is removed
from the observer list.
<BR><B>NOTE:<B> The default is to have the feature disabled.
</TD>
</TR>
<!-- <TR NAME="ECScheduling"> -->
<TR>
<TD><CODE>-ECScheduling</CODE>
<EM>scheduling_strategy</EM>
</TD>
<TD>The event channel can collaborate with the scheduling
service to build the dependency list between the consumers
and the suppliers.
If the <EM>null</EM> scheduling strategy is selected this
feature is disabled,
the <EM>priority</EM> strategy (sched factory only) enables this feature.
<BR><B>NOTE:<B> The default is to have the feature disabled.
</TD>
</TR>
<!-- <TR NAME="ECProxyConsumerLock"> -->
<TR>
<TD><CODE>-ECProxyConsumerLock</CODE>
<EM>lock_type</EM>
</TD>
<TD>Select the lock type (<EM>null</EM>, <EM>thread</EM> or
<EM>recursive</EM>) to synchronize access to the
ProxyPushConsumer state.
</TD>
</TR>
<!-- <TR NAME="ECProxySupplierLock"> -->
<TR>
<TD><CODE>-ECProxySupplierLock</CODE>
<EM>lock_type</EM>
</TD>
<TD>Select the lock type (<EM>null</EM>, <EM>thread</EM> or
<EM>recursive</EM>) to synchronize access to the
ProxyPushSupplier state.
</TD>
</TR>
<!-- <TR NAME="ECUseORBId"> -->
<TR>
<TD><CODE>-ECUseORBId</CODE>
<EM>orbid</EM>
</TD>
<TD>Set the name of the ORB used by the event service, only
useful in applications that create multiple ORBs and
activate the event service in one of them.
</TD>
</TR>
<!-- <TR NAME="ECConsumerControl"> -->
<TR>
<TD><CODE>-ECConsumerControl</CODE>
<EM>policy</EM>
</TD>
<TD>Select the consumer control policy (<EM>null</EM> or
<EM>reactive</EM>) to detect and discard broken consumers.
</TD>
</TR>
<!-- <TR NAME="ECSupplierControl"> -->
<TR>
<TD><CODE>-ECSupplierControl</CODE>
<EM>policy</EM>
</TD>
<TD>Select the supplier control policy (<EM>null</EM> or
<EM>reactive</EM>) to detect and discard broken suppliers.
</TD>
</TR>
<!-- <TR NAME="ECConsumerControlPeriod"> -->
<TR>
<TD><CODE>-ECConsumerControlPeriod</CODE>
<EM>period</EM>
</TD>
<TD>Set the period (in microseconds) used by the reactive
consumer control policy (set <EM>ECConsumerControl</EM> to
<EM>reactive</EM>) to poll the state of the consumers.
When set to 0 there is no polling but the
reactive strategy is in place.
</TD>
</TR>
<!-- <TR NAME="ECSupplierControlPeriod"> -->
<TR>
<TD><CODE>-ECSupplierControlPeriod</CODE>
<EM>period</EM>
</TD>
<TD>Set the period (in microseconds) used by the reactive
supplier control policy (set <EM>ECSupplierControl</EM> to
<EM>reactive</EM>) to poll the state of the suppliers.
When set to 0 there is no polling but the
reactive strategy is in place.
</TD>
</TR>
<!-- <TR NAME="ECConsumerControlTimeout"> -->
<TR>
<TD><CODE>-ECConsumerControlTimeout</CODE>
<EM>timeout</EM>
</TD>
<TD>Set the timeout period (in microseconds) used by the reactive
consumer control policy (set <EM>ECConsumerControl</EM> to
<EM>reactive</EM>) to detect a timeout when polling the state
of the consumers.
</TD>
</TR>
<!-- <TR NAME="ECSupplierControlTimeout"> -->
<TR>
<TD><CODE>-ECSupplierControlTimeout</CODE>
<EM>timeout</EM>
</TD>
<TD>Set the timeout period (in microseconds) used by the reactive
supplier control policy (set <EM>ECSupplierControl</EM> to
<EM>reactive</EM>) to detect a timeout when polling the state
of the suppliers.
</TD>
</TR>
<!-- <TR NAME="ECProxyPushConsumerCollection"> -->
<TR>
<TD><CODE>-ECProxyPushConsumerCollection</CODE>
<EM>flag[:flags]</EM>
</TD>
<TD><P>Configure the data structure and strategies used to
implement collections of
<CODE>ProxyPushConsumers</CODE>.
The argument is a colon separated list of flags, with
the following semantics:
<TABLE BORDER="1" CELLSPACING="2" CELLPADDING="0">
<TR><TH>Flag</TH><TH>Description</TH>
</TR>
<TR>
<TD>MT</TD>
<TD>Use regular mutexes and/or condition
variables for serialization.
</TD>
</tr>
<TR>
<TD>ST</TD>
<TD>Use null mutexes and/or condition
variables for serialization.
</TD>
</tr>
<TR>
<TD>LIST</TD>
<TD>Implement the collection using an ordered list,
fast for iteration (i.e. during event dispatching),
but slow for insertion and removal (i.e. when
clients connect and disconnect from the EC).
</TD>
</tr>
<TR>
<TD>RB_TREE</TD>
<TD>Implement the collection using a Red-Black tree,
slow for iteration (i.e. during event dispatching),
but fast for insertion and removal (i.e. when
clients connect and disconnect from the EC).
</TD>
</tr>
<TR>
<TD>IMMEDIATE</TD>
<TD>Threads block until they can execute a change on
the data structure, the system must use other
approaches to guarantee that the iterators are not
invalidated during event dispatching. For example,
use a separate dispatching thread. Using this option
with the reactive values for any of the
-ECSupplierControl, -ECConsumerControl, or
-ECDispatching options may cause deadlocks.
</TD>
</tr>
<TR>
<TD>COPY_ON_READ</TD>
<TD>Before initiating an iteration to dispatch events
(or similar tasks) a copy of the complete collection
is performed.
This solves most of the synchronization problems,
but introduces a significant source of overhead and
priority inversions on the critical path.
</TD>
</tr>
<TR>
<TD>COPY_ON_WRITE</TD>
<TD>Similar to the previous one, but the copy is only
performed when needed.
</TD>
</tr>
<TR>
<TD>DELAYED</TD>
<TD>Threads that need to change the collection can
detect if that change will invalidate iterators used
by other threads.
If so, the thread posts the change on a queue that
is executed once the collection is no longer in
use.
</TD>
</TR>
</TABLE>
</P>
</TD>
</TR>
<!-- <TR NAME="ECProxyPushSupplierCollection"> -->
<TR>
<TD><CODE>-ECProxyPushSupplierCollection</CODE>
<EM>flag[:flags]</EM>
</TD>
<TD><P>Configure the data structure and strategies used to
implement collections of <CODE>ProxyPushSupplier</CODE>
objects.
Use the same arguments as with the
<CODE>ECProxyPushConsumerCollection</CODE> option.
</P>
</TD>
</TR>
<!-- <TR NAME="ECPushSupplierSet"> -->
<TR>
<TD><CODE>-ECPushSupplierSet</CODE>
</TD>
<TD><P>Obsolete option, ignored.
</P>
</TD>
</TR>
<!-- <TR NAME="ECConsumerAdminLock"> -->
<TR>
<TD><CODE>-ECConsumerAdminLock</CODE>
</TD>
<TD>Obsolete option, ignored in the current version.
</TD>
</TR>
<!-- <TR NAME="ECSupplierAdminLock"> -->
<TR>
<TD><CODE>-ECSupplierAdminLock</CODE>
</TD>
<TD>Obsolete option, ignored in the current version.
</TD>
</TR>
<!-- <TR NAME="ECConsumerValidateConnection"> -->
<TR>
<TD><CODE>-ECConsumerValidateConnection</CODE>
<EM>validate_connection: 0 | 1</EM>
</TD>
<TD>When this option is set the connection from the Event Channel
to the consumer will be created during the connect of the
consumer, just before the consumer is added to the consumer
list. By default
the Event Channel will create the connection to the consumer at
the moment the first event is pushed to the consumer.
When the network is heavily loaded during this connect and a new event
is pushed before the connection is establed, a new create connection
request is done. When having very high connection establishment
time (for example running on a WAN) and an interval that is much
smaller than the connection establishment time it is wise to
set this option. Else you get dozens of new connection request
that can result in a stack overflow. Another option is to use BiDIR
GIOP so that there is only one connection between Rtec and consumer
but for this the Rtec and the consumer must be changed to set the
BiDIR Policy, this is not implemented at this moment.
</TD>
</TR>
</TABLE>
</P>
<H3>The constructor</H3>
<P>The <CODE>TAO_EC_Event_Channel</CODE> class implements the
<CODE>RtecEventChannelAdmin::EventChannel</CODE> interface;
this class takes one mandatory and two optional parameters in
its constructor:
</P>
<PRE>
TAO_EC_Event_Channel (const TAO_EC_Event_Channel_Attributes& attributes,
TAO_EC_Factory* factory = 0,
int own_factory = 0);
</PRE>
<P>The <CODE>factory</CODE> is an optional parameter to override
the default strategy factory used by the event channel,
the event channel will destroy the factory if the
<CODE>own_factory</CODE> argument is true.
</P>
<P>The <CODE>attributes</CODE> parameter can be used to fine tune
some of the algorithms and strategies used by the event channel,
the default values are probably OK for most applications.
Notice that the attributes include the POA used to activate the
ConsumerAdmin, SupplierAdmin, ProxyPushConsumer and
ProxyPushSupplier objects;
these POAs must have the <CODE>IMPLICIT_ACTIVATION</CODE> and the
<CODE>SYSTEM_ID</CODE> policies (as the RootPOA does).
</P>
<P><TABLE BORDER="2" CELLSPACING="2" CELLPADDING="0">
<TR><TH>Attribute</TH><TH>Description</TH></TR>
<TR><TD><CODE>consumer_reconnect</CODE></TD>
<TD>If the attribute is not zero then the same consumer can
call <CODE>connect_push_consumer</CODE> on its
ProxyPushSupplier multiple times to change its
subscriptions;
this is usually more efficient that disconnecting and
connecting again.
</TD>
</TR>
<TR><TD><CODE>supplier_reconnect</CODE></TD>
<TD>If the attribute is not zero then the same supplier can
call <CODE>connect_push_supplier</CODE> on its
ProxyPushConsumer multiple times to change its
publications;
this is usually more efficient that disconnecting and
connecting again.
</TD>
</TR>
<TR><TD><CODE>busy_hwm</CODE></TD>
<TD>When the delayed flag is set on proxy collections,
this flag controls the maximum
number of threads that can simultaneously iterate over the
collection before blocking.
It can be used to avoid starvation in delayed updates on
the collection.
</TD>
</TR>
<TR><TD><CODE>max_write_delay</CODE></TD>
<TD>When the delayed flag is set on proxy collections,
this flag controls the maximum
number of threads that will initiate dispatching
<B>after</B> a change has been posted.
Any thread after that is blocked until the operations are
performed.
It can be used to completely stop starvation of delayed
updates on the collection.
</TD>
</TR>
<TR><TD><CODE>scheduler</CODE></TD>
<TD>Most configurations of the real-time event channel do
not require an scheduler.
If any of the strategies that require an scheduling
service is selected then this attribute should be set
appropiately.
</TD>
</TR>
<TR><TD><CODE>supplier_poa</CODE></TD>
<TD>The POA used by the event channel to activate SupplierAdmin
and SupplierProxy objects.
</TD>
</TR>
<TR><TD><CODE>consumer_poa</CODE></TD>
<TD>The POA used by the event channel to activate ConsumerAdmin
and ConsumerProxy objects.
</TD>
</TR>
<TR><TD><CODE>disconnect_callbacks</CODE></TD>
<TD>If not zero, then the event channel sends disconnect
callbacks when a disconnect method is called on a Proxy.
For example, if a consumer calls
disconnect_push_supplier() on its proxy the EC
invokes disconnect_push_consumer() on the consumer.
An analogous call is also made for suppliers when this
attribute is set.
By default, these callbacks are not made in this situation.
</TD>
</TR>
</TABLE>
</P>
<H3>Configuring the IIOP Gateway</H3>
<P>The <CODE>TAO_EC_Gateway_IIOP_Factory</CODE> is the factory for
the <CODE>TAO_EC_Gateway_IIOP</CODE> class. This factory can be
used to configure the settings of the IIOP Gateway using the
svc.conf file. The contents looks like this:
</P>
<PRE>
# Comments go here...
# More comments if you want to...
static EC_Gateway_IIOP_Factory "-ECGIIOPConsumerECControl null ....."
</PRE>
<P>All the IIOP Gateway factory options start with
<CODE>-ECGIIOP</CODE></P>
<P><TABLE BORDER="2" CELLSPACING="2" CELLPADDING="0">
<TR>
<TH>Option</TH>
<TH>Description</TH>
</TR>
<!-- <TR NAME="ECGIIOPConsumerECControl"> -->
<TR>
<TD><CODE>-ECGIIOPConsumerECControl</CODE>
<EM>policy</EM>
</TD>
<TD>Select the consumer ec control policy (<EM>null</EM> or
<EM>reactive</EM> or <EM>reconnect</EM>) to detect and handle
broken consumer ec's.
</TD>
</TR>
<!-- <TR NAME="ECGIIOPConsumerECControlPeriod"> -->
<TR>
<TD><CODE>-ECGIIOPConsumerECControlPeriod</CODE>
<EM>period</EM>
</TD>
<TD>Set the period (in microseconds) used by the reactive and reconnect
consumer ec control policy (set <EM>ECGIIOPConsumerECControl</EM> to
<EM>reactive</EM> or <EM>reconnect</EM>) to poll the state of the consumer ec.
When set to 0 there is no polling but the
reactive strategy is in place.
</TD>
</TR>
<!-- <TR NAME="ECGIIOPConsumerECControlTimeout"> -->
<TR>
<TD><CODE>-ECGIIOPConsumerECControlTimeout</CODE>
<EM>timeout</EM>
</TD>
<TD>Set the timeout period (in microseconds) used by the reactive and reconnect
consumer ec control policy (set <EM>ECGIIOPConsumerECControl</EM> to
<EM>reactive</EM> or <EM>reconnect</EM>) to detect a timeout when polling the state
of the consumer ec.
</TD>
</TR>
<!-- <TR NAME="ECGIIOPUseORBId"> -->
<TR>
<TD><CODE>-ECGIIOPUseORBId</CODE>
<EM>orbid</EM>
</TD>
<TD>Set the name of the ORB used by the event gateway, only
useful in applications that create multiple ORBs and
activate the gateway in one of them.
</TD>
</TR>
<!-- <TR NAME="ECGIIOPUseTTL"> -->
<TR>
<TD><CODE>-ECGIIOPUseTTL</CODE>
<EM>use_ttl: 0 | 1</EM>
</TD>
<TD>Set whether the IIOP Gateway uses the TTL or not.
This is 1 by default. When set to 0 make sure that
no recursive structure is build between ec's, else an
event can keep looping for ever. Useful when there are no
recursive structures and we want the gateway to
transfer all events independent of their TTL because suppliers
can be unaware about the maximum number of hops. In case
this option is 0, the TTL in the event isn't decremented
by the gateway also.
</TD>
</TR>
<!-- <TR NAME="ECGIIOPUseConsumerProxyMap"> -->
<TR>
<TD><CODE>-ECGIIOPUseConsumerProxyMap</CODE>
<EM>use_consumer_proxy_map: 0 | 1</EM>
</TD>
<TD>Set whether the IIOP Gateway uses a map with a proxy
push consumer for each unique source id or not. This is 1
by default meaning that a map is used. When set to 0 the
gateway will just use one proxy push consumer to push
events to the consumer ec. This options is useful when
a lot of different source id's are used but there is no
need for a different proxy push consumer for each source id.
Setting this option to 0 then improves the performance.
</TD>
</TR>
</TABLE>
</P>
<H3>The commandline arguments</H3>
The Event_Service executable has several commandline arguments you can use.
The following arguments are available.
<P><TABLE BORDER="2" CELLSPACING="2" CELLPADDING="0">
<TR>
<TH>Option</TH>
<TH>Description</TH>
</TR>
<!-- <TR NAME="-d"> -->
<TR>
<TD><CODE>-n</CODE>
<EM>service_name</EM>
</TD>
<TD>The name with which the Event Service registers itself in the
Naming Service.
</TD>
</TR>
<!-- <TR NAME="-o"> -->
<TR>
<TD><CODE>-o</CODE>
<EM>ior_file_name</EM>
</TD>
<TD>The file to which the IOR of the Event Service will be written.
</TD>
</TR>
<!-- <TR NAME="-p"> -->
<TR>
<TD><CODE>-p</CODE>
<EM>pid_file_name</EM>
</TD>
<TD>The process id of the Event Service will be written to this
file
</TD>
</TR>
<!-- <TR NAME="-q"> -->
<TR>
<TD><CODE>-q</CODE>
<EM>ec_object_id</EM>
</TD>
<TD>The object ID for the Event Channel that will be used
when a Persistent IOR is generated
</TD>
</TR>
<!-- <TR NAME="-b"> -->
<TR>
<TD><CODE>-b</CODE>
<EM></EM>
</TD>
<TD>Use BiDIR GIOP
</TD>
</TR>
<!-- <TR NAME="-x"> -->
<TR>
<TD><CODE>-x</CODE>
<EM></EM>
</TD>
<TD>Don't register the Event Service to the Naming Service
</TD>
</TR>
<!-- <TR NAME="-s"> -->
<TR>
<TD><CODE>-s</CODE>
<EM>global|local|none</EM>
</TD>
<TD>Which scheduler should be used. The default is <CODE>none</CODE>.
With <CODE>local</CODE> an in process scheduler is created. With
<CODE>global</CODE> a scheduler is retrieved from the Naming Service
</TD>
</TR>
</TABLE>
</P>
<P><HR><P>
Back to the TAO <A HREF="index.html">components documentation</A>.
<!--#include virtual="/~schmidt/cgi-sig.html" -->
<!-- <address><a href="mailto:coryan@cs.wustl.edu">Carlos O'Ryan</a></address>-->
<!-- Created: Thu Jul 1 21:44:28 CDT 1999 -->
<!-- hhmts start -->
Last modified: Tue Oct 18 13:13:54 CDT 2005
<!-- hhmts end -->
</body>
</html>
|
