forked from ReactiveX/RxJava
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathBackpressureTests.java
More file actions
671 lines (583 loc) · 28 KB
/
BackpressureTests.java
File metadata and controls
671 lines (583 loc) · 28 KB
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
/**
* Copyright 2014 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rx;
import static org.junit.Assert.*;
import java.util.List;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import org.junit.*;
import org.junit.rules.TestName;
import rx.Observable.OnSubscribe;
import rx.exceptions.MissingBackpressureException;
import rx.functions.*;
import rx.internal.util.RxRingBuffer;
import rx.observers.TestSubscriber;
import rx.schedulers.Schedulers;
import rx.test.TestObstructionDetection;
public class BackpressureTests {
@Rule
public TestName testName = new TestName();
@After
public void doAfterTest() {
TestObstructionDetection.checkObstruction();
}
@Test
public void testObserveOn() {
int NUM = (int) (RxRingBuffer.SIZE * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
incrementingIntegers(c).observeOn(Schedulers.computation()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testObserveOn => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get());
assertEquals(NUM, ts.getOnNextEvents().size());
assertTrue(c.get() < RxRingBuffer.SIZE * 4);
}
@Test
public void testObserveOnWithSlowConsumer() {
int NUM = (int) (RxRingBuffer.SIZE * 0.2);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
incrementingIntegers(c).observeOn(Schedulers.computation()).map(new Func1<Integer, Integer>() {
@Override
public Integer call(Integer i) {
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
return i;
}
}).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testObserveOnWithSlowConsumer => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get());
assertEquals(NUM, ts.getOnNextEvents().size());
assertTrue(c.get() < RxRingBuffer.SIZE * 2);
}
@Test
public void testMergeSync() {
int NUM = (int) (RxRingBuffer.SIZE * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
Observable<Integer> merged = Observable.merge(incrementingIntegers(c1), incrementingIntegers(c2));
merged.take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("Expected: " + NUM + " got: " + ts.getOnNextEvents().size());
System.out.println("testMergeSync => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c1.get() + " / " + c2.get());
assertEquals(NUM, ts.getOnNextEvents().size());
// either one can starve the other, but neither should be capable of doing more than 5 batches (taking 4.1)
// TODO is it possible to make this deterministic rather than one possibly starving the other?
// benjchristensen => In general I'd say it's not worth trying to make it so, as "fair" algoritms generally take a performance hit
assertTrue(c1.get() < RxRingBuffer.SIZE * 5);
assertTrue(c2.get() < RxRingBuffer.SIZE * 5);
}
@Test
public void testMergeAsync() {
int NUM = (int) (RxRingBuffer.SIZE * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
Observable<Integer> merged = Observable.merge(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()));
merged.take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testMergeAsync => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c1.get() + " / " + c2.get());
assertEquals(NUM, ts.getOnNextEvents().size());
// either one can starve the other, but neither should be capable of doing more than 5 batches (taking 4.1)
// TODO is it possible to make this deterministic rather than one possibly starving the other?
// benjchristensen => In general I'd say it's not worth trying to make it so, as "fair" algoritms generally take a performance hit
assertTrue(c1.get() < RxRingBuffer.SIZE * 5);
assertTrue(c2.get() < RxRingBuffer.SIZE * 5);
}
@Test
public void testMergeAsyncThenObserveOnLoop() {
for (int i = 0; i < 500; i++) {
if (i % 10 == 0) {
System.out.println("testMergeAsyncThenObserveOnLoop >> " + i);
}
// Verify there is no MissingBackpressureException
int NUM = (int) (RxRingBuffer.SIZE * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
Observable<Integer> merged = Observable.merge(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()));
merged.observeOn(Schedulers.io()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testMergeAsyncThenObserveOn => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c1.get() + " / " + c2.get());
assertEquals(NUM, ts.getOnNextEvents().size());
}
}
@Test
public void testMergeAsyncThenObserveOn() {
int NUM = (int) (RxRingBuffer.SIZE * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
Observable<Integer> merged = Observable.merge(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()));
merged.observeOn(Schedulers.newThread()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testMergeAsyncThenObserveOn => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c1.get() + " / " + c2.get());
assertEquals(NUM, ts.getOnNextEvents().size());
// either one can starve the other, but neither should be capable of doing more than 5 batches (taking 4.1)
// TODO is it possible to make this deterministic rather than one possibly starving the other?
// benjchristensen => In general I'd say it's not worth trying to make it so, as "fair" algoritms generally take a performance hit
// akarnokd => run this in a loop over 10k times and never saw values get as high as 7*SIZE, but since observeOn delays the unsubscription non-deterministically, the test will remain unreliable
assertTrue(c1.get() < RxRingBuffer.SIZE * 7);
assertTrue(c2.get() < RxRingBuffer.SIZE * 7);
}
@Test
public void testFlatMapSync() {
int NUM = (int) (RxRingBuffer.SIZE * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
incrementingIntegers(c).flatMap(new Func1<Integer, Observable<Integer>>() {
@Override
public Observable<Integer> call(Integer i) {
return incrementingIntegers(new AtomicInteger()).take(10);
}
}).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testFlatMapSync => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get());
assertEquals(NUM, ts.getOnNextEvents().size());
// expect less than 1 buffer since the flatMap is emitting 10 each time, so it is NUM/10 that will be taken.
assertTrue(c.get() < RxRingBuffer.SIZE);
}
@Test
@Ignore // the test is non-deterministic and can't be made deterministic
public void testFlatMapAsync() {
int NUM = (int) (RxRingBuffer.SIZE * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
incrementingIntegers(c).subscribeOn(Schedulers.computation()).flatMap(new Func1<Integer, Observable<Integer>>() {
@Override
public Observable<Integer> call(Integer i) {
return incrementingIntegers(new AtomicInteger()).take(10).subscribeOn(Schedulers.computation());
}
}).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testFlatMapAsync => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get() + " Size: " + RxRingBuffer.SIZE);
assertEquals(NUM, ts.getOnNextEvents().size());
// even though we only need 10, it will request at least RxRingBuffer.SIZE, and then as it drains keep requesting more
// and then it will be non-deterministic when the take() causes the unsubscribe as it is scheduled on 10 different schedulers (threads)
// normally this number is ~250 but can get up to ~1200 when RxRingBuffer.SIZE == 1024
assertTrue(c.get() <= RxRingBuffer.SIZE * 2);
}
@Test
public void testZipSync() {
int NUM = (int) (RxRingBuffer.SIZE * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
Observable<Integer> zipped = Observable.zip(
incrementingIntegers(c1),
incrementingIntegers(c2),
new Func2<Integer, Integer, Integer>() {
@Override
public Integer call(Integer t1, Integer t2) {
return t1 + t2;
}
});
zipped.take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testZipSync => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c1.get() + " / " + c2.get());
assertEquals(NUM, ts.getOnNextEvents().size());
assertTrue(c1.get() < RxRingBuffer.SIZE * 5);
assertTrue(c2.get() < RxRingBuffer.SIZE * 5);
}
@Test
public void testZipAsync() {
int NUM = (int) (RxRingBuffer.SIZE * 2.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
Observable<Integer> zipped = Observable.zip(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()),
new Func2<Integer, Integer, Integer>() {
@Override
public Integer call(Integer t1, Integer t2) {
return t1 + t2;
}
});
zipped.take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testZipAsync => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c1.get() + " / " + c2.get());
assertEquals(NUM, ts.getOnNextEvents().size());
assertTrue(c1.get() < RxRingBuffer.SIZE * 3);
assertTrue(c2.get() < RxRingBuffer.SIZE * 3);
}
@Test
public void testSubscribeOnScheduling() {
// in a loop for repeating the concurrency in this to increase chance of failure
for (int i = 0; i < 100; i++) {
int NUM = (int) (RxRingBuffer.SIZE * 2.1);
AtomicInteger c = new AtomicInteger();
ConcurrentLinkedQueue<Thread> threads = new ConcurrentLinkedQueue<Thread>();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
// observeOn is there to make it async and need backpressure
incrementingIntegers(c, threads).subscribeOn(Schedulers.computation()).observeOn(Schedulers.computation()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testSubscribeOnScheduling => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get());
assertEquals(NUM, ts.getOnNextEvents().size());
assertTrue(c.get() < RxRingBuffer.SIZE * 4);
Thread first = null;
for (Thread t : threads) {
System.out.println("testSubscribeOnScheduling => thread: " + t);
if (first == null) {
first = t;
} else {
if (!first.equals(t)) {
fail("Expected to see the same thread");
}
}
}
System.out.println("testSubscribeOnScheduling => Number of batch requests seen: " + threads.size());
assertTrue(threads.size() > 1);
System.out.println("-------------------------------------------------------------------------------------------");
}
}
@Test
public void testTakeFilterSkipChainAsync() {
int NUM = (int) (RxRingBuffer.SIZE * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
incrementingIntegers(c).observeOn(Schedulers.computation())
.skip(10000)
.filter(new Func1<Integer, Boolean>() {
@Override
public Boolean call(Integer i) {
return i > 11000;
}
}).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
// emit 10000 that are skipped
// emit next 1000 that are filtered out
// take NUM
// so emitted is at least 10000+1000+NUM + extra for buffer size/threshold
int expected = 10000 + 1000 + RxRingBuffer.SIZE * 3 + RxRingBuffer.SIZE / 2;
System.out.println("testTakeFilterSkipChain => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get() + " Expected: " + expected);
assertEquals(NUM, ts.getOnNextEvents().size());
assertTrue(c.get() < expected);
}
@Test
public void testUserSubscriberUsingRequestSync() {
AtomicInteger c = new AtomicInteger();
final AtomicInteger totalReceived = new AtomicInteger();
final AtomicInteger batches = new AtomicInteger();
final AtomicInteger received = new AtomicInteger();
incrementingIntegers(c).subscribe(new Subscriber<Integer>() {
@Override
public void onStart() {
request(100);
}
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
}
@Override
public void onNext(Integer t) {
int total = totalReceived.incrementAndGet();
received.incrementAndGet();
if (total >= 2000) {
unsubscribe();
}
if (received.get() == 100) {
batches.incrementAndGet();
request(100);
received.set(0);
}
}
});
System.out.println("testUserSubscriberUsingRequestSync => Received: " + totalReceived.get() + " Emitted: " + c.get() + " Request Batches: " + batches.get());
assertEquals(2000, c.get());
assertEquals(2000, totalReceived.get());
assertEquals(20, batches.get());
}
@Test
public void testUserSubscriberUsingRequestAsync() throws InterruptedException {
AtomicInteger c = new AtomicInteger();
final AtomicInteger totalReceived = new AtomicInteger();
final AtomicInteger received = new AtomicInteger();
final AtomicInteger batches = new AtomicInteger();
final CountDownLatch latch = new CountDownLatch(1);
incrementingIntegers(c).subscribeOn(Schedulers.newThread()).subscribe(new Subscriber<Integer>() {
@Override
public void onStart() {
request(100);
}
@Override
public void onCompleted() {
latch.countDown();
}
@Override
public void onError(Throwable e) {
latch.countDown();
}
@Override
public void onNext(Integer t) {
int total = totalReceived.incrementAndGet();
received.incrementAndGet();
boolean done = false;
if (total >= 2000) {
done = true;
unsubscribe();
}
if (received.get() == 100) {
batches.incrementAndGet();
received.set(0);
if (!done) {
request(100);
}
}
if (done) {
latch.countDown();
}
}
});
latch.await();
System.out.println("testUserSubscriberUsingRequestAsync => Received: " + totalReceived.get() + " Emitted: " + c.get() + " Request Batches: " + batches.get());
assertEquals(2000, c.get());
assertEquals(2000, totalReceived.get());
assertEquals(20, batches.get());
}
@Test(timeout = 2000)
public void testFirehoseFailsAsExpected() {
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
firehose(c).observeOn(Schedulers.computation()).map(SLOW_PASS_THRU).subscribe(ts);
ts.awaitTerminalEvent();
System.out.println("testFirehoseFailsAsExpected => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get());
assertEquals(1, ts.getOnErrorEvents().size());
assertTrue(ts.getOnErrorEvents().get(0) instanceof MissingBackpressureException);
}
@Test(timeout = 10000)
public void testOnBackpressureDrop() {
long t = System.currentTimeMillis();
for (int i = 0; i < 100; i++) {
// stop the test if we are getting close to the timeout because slow machines
// may not get through 100 iterations
if (System.currentTimeMillis() - t > TimeUnit.SECONDS.toMillis(9)) {
break;
}
int NUM = (int) (RxRingBuffer.SIZE * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
firehose(c).onBackpressureDrop()
.observeOn(Schedulers.computation())
.map(SLOW_PASS_THRU).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.getOnNextEvents();
assertEquals(NUM, onNextEvents.size());
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println("testOnBackpressureDrop => Received: " + onNextEvents.size() + " Emitted: " + c.get() + " Last value: " + lastEvent);
// it drop, so we should get some number far higher than what would have sequentially incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
}
}
@Test(timeout = 10000)
public void testOnBackpressureDropWithAction() {
for (int i = 0; i < 100; i++) {
final AtomicInteger emitCount = new AtomicInteger();
final AtomicInteger dropCount = new AtomicInteger();
final AtomicInteger passCount = new AtomicInteger();
final int NUM = RxRingBuffer.SIZE * 3; // > 1 so that take doesn't prevent buffer overflow
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
firehose(emitCount).onBackpressureDrop(new Action1<Integer>() {
@Override
public void call(Integer i) {
dropCount.incrementAndGet();
}
})
.doOnNext(new Action1<Integer>() {
@Override
public void call(Integer integer) {
passCount.incrementAndGet();
}
})
.observeOn(Schedulers.computation())
.map(SLOW_PASS_THRU).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.getOnNextEvents();
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println(testName.getMethodName() + " => Received: " + onNextEvents.size() + " Passed: " + passCount.get() + " Dropped: " + dropCount.get() + " Emitted: " + emitCount.get() + " Last value: " + lastEvent);
assertEquals(NUM, onNextEvents.size());
// in reality, NUM < passCount
assertTrue(NUM <= passCount.get());
// it drop, so we should get some number far higher than what would have sequentially incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
assertTrue(0 < dropCount.get());
assertEquals(emitCount.get(), passCount.get() + dropCount.get());
}
}
@Test(timeout = 10000)
public void testOnBackpressureDropSynchronous() {
for (int i = 0; i < 100; i++) {
int NUM = (int) (RxRingBuffer.SIZE * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
firehose(c).onBackpressureDrop()
.map(SLOW_PASS_THRU).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.getOnNextEvents();
assertEquals(NUM, onNextEvents.size());
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println("testOnBackpressureDrop => Received: " + onNextEvents.size() + " Emitted: " + c.get() + " Last value: " + lastEvent);
// it drop, so we should get some number far higher than what would have sequentially incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
}
}
@Test(timeout = 10000)
public void testOnBackpressureDropSynchronousWithAction() {
for (int i = 0; i < 100; i++) {
final AtomicInteger dropCount = new AtomicInteger();
int NUM = (int) (RxRingBuffer.SIZE * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
firehose(c).onBackpressureDrop(new Action1<Integer>() {
@Override
public void call(Integer i) {
dropCount.incrementAndGet();
}
})
.map(SLOW_PASS_THRU).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.getOnNextEvents();
assertEquals(NUM, onNextEvents.size());
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println("testOnBackpressureDrop => Received: " + onNextEvents.size() + " Dropped: " + dropCount.get() + " Emitted: " + c.get() + " Last value: " + lastEvent);
// it drop, so we should get some number far higher than what would have sequentially incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
// no drop in synchronous mode
assertEquals(0, dropCount.get());
assertEquals(c.get(), onNextEvents.size());
}
}
@Test(timeout = 2000)
public void testOnBackpressureBuffer() {
int NUM = (int) (RxRingBuffer.SIZE * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
firehose(c).takeWhile(new Func1<Integer, Boolean>() {
@Override
public Boolean call(Integer t1) {
return t1 < 100000;
}
}).onBackpressureBuffer().observeOn(Schedulers.computation()).map(SLOW_PASS_THRU).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testOnBackpressureBuffer => Received: " + ts.getOnNextEvents().size() + " Emitted: " + c.get());
assertEquals(NUM, ts.getOnNextEvents().size());
// it buffers, so we should get the right value sequentially
assertEquals(NUM - 1, ts.getOnNextEvents().get(NUM - 1).intValue());
}
/**
* A synchronous Observable that will emit incrementing integers as requested.
*
* @param counter
* @return
*/
private static Observable<Integer> incrementingIntegers(final AtomicInteger counter) {
return incrementingIntegers(counter, null);
}
private static Observable<Integer> incrementingIntegers(final AtomicInteger counter, final ConcurrentLinkedQueue<Thread> threadsSeen) {
return Observable.create(new OnSubscribe<Integer>() {
final AtomicLong requested = new AtomicLong();
@Override
public void call(final Subscriber<? super Integer> s) {
s.setProducer(new Producer() {
int i = 0;
@Override
public void request(long n) {
if (n == 0) {
// nothing to do
return;
}
if (threadsSeen != null) {
threadsSeen.offer(Thread.currentThread());
}
long _c = requested.getAndAdd(n);
if (_c == 0) {
while (!s.isUnsubscribed()) {
counter.incrementAndGet();
s.onNext(i++);
if (requested.decrementAndGet() == 0) {
// we're done emitting the number requested so return
return;
}
}
}
}
});
}
});
}
/**
* Incrementing int without backpressure.
*
* @param counter
* @return
*/
private static Observable<Integer> firehose(final AtomicInteger counter) {
return Observable.create(new OnSubscribe<Integer>() {
int i = 0;
@Override
public void call(final Subscriber<? super Integer> s) {
while (!s.isUnsubscribed()) {
s.onNext(i++);
counter.incrementAndGet();
}
System.out.println("unsubscribed after: " + i);
}
});
}
final static Func1<Integer, Integer> SLOW_PASS_THRU = new Func1<Integer, Integer>() {
volatile int sink;
@Override
public Integer call(Integer t1) {
// be slow ... but faster than Thread.sleep(1)
String t = "";
int s = sink;
for (int i = 1000; i >= 0; i--) {
t = String.valueOf(i + t.hashCode() + s);
}
sink = t.hashCode();
return t1;
}
};
}