Releases · ReactiveX/RxJava

03 Jun 16:29

0.19.0

5ada2fc

0.19.0

This release focused on performance and cleanup. If all goes according to plan the next release should be 0.20.0 with backpressure and then we will release 1.0 Release Candidate with the public API no longer allowing breaking changes.

Performance and Object Allocation

Fairly significant object allocation improvements are included in this release which reduce GC pressure and improve performance.

Two pull requests (amongst several) with details are:

#1281 Reduce Subscription Object Allocation
#1246 Moved to atomic field updaters

With the following simple test code relative performance has increased as shown below:

Observable<Integer> o = Observable.just(1);
o.map(i -> {
    return String.valueOf(i);
}).map(i -> {
    return Integer.parseInt(i);
}).subscribe(observer);

Rx 0.19

Run: 10 - 10,692,099 ops/sec 
Run: 11 - 10,617,627 ops/sec 
Run: 12 - 10,938,405 ops/sec 
Run: 13 - 10,917,388 ops/sec 
Run: 14 - 10,783,298 ops/sec

Rx 0.18.4

Run: 11 - 8,493,506 ops/sec 
Run: 12 - 8,403,361 ops/sec 
Run: 13 - 8,400,537 ops/sec 
Run: 14 - 8,163,998 ops/sec

Rx 0.17.6

Run: 10 - 4,930,966 ops/sec 
Run: 11 - 6,119,951 ops/sec 
Run: 12 - 7,062,146 ops/sec 
Run: 13 - 6,514,657 ops/sec 
Run: 14 - 6,369,426 ops/sec

Rx 0.16.1

Run: 10 - 2,879,355 ops/sec 
Run: 11 - 3,236,245 ops/sec 
Run: 12 - 4,468,275 ops/sec 
Run: 13 - 3,237,293 ops/sec 
Run: 14 - 4,683,840 ops/sec

Note that these numbers are relative as they depend on the JVM and hardware.

Scala Changes

Many missing operators have been added to the RxScala APIs along with fixes and other maturation.

toBlockingObservable() -> toBlocking()

The toBlockingObservable() method has been deprecated in favor of toBlocking() for brevity and fit better with possible future additions such as toParallel() without always needing the Observable suffix.

forEach

forEach as added as an alias for subscribe to match the Java 8 naming convention.

This means code can now be written as:

Observable.from(1, 2, 3).limit(2).forEach(System.out::println);

which is an alias of this:

Observable.from(1, 2, 3).take(2).subscribe(System.out::println);

Since forEach exists on BlockingObservable as well, moving from non-blocking to blocking looks like this:

// non-blocking
Observable.from(1, 2, 3).limit(2).forEach(System.out::println);
// blocking
Observable.from(1, 2, 3).limit(2).toBlocking().forEach(System.out::println);

Schedulers

Thread caching is restored to Schedulers.io() after being lost in v0.18.

A replacement for ExecutorScheduler (removed in 0.18) is accessible via Schedulers.from(Executor e) that wraps an Executor and complies with the Rx contract.

ReplaySubject

All "replay" functionality now exists directly on the ReplaySubject rather than in an internal type. This means there are now several different create methods with the various overloads of size and time.

Changelist

Pull 1165 RxScala: Add dropUntil, contains, repeat, doOnTerminate, startWith, publish variants
Pull 1183 NotificationLite.accept performance improvements
Pull 1177 GroupByUntil to use BufferUntilSubscriber
Pull 1182 Add facilities for creating Observables from JavaFX events and ObservableValues
Pull 1188 RxScala Schedulers changes
Pull 1175 Fixed synchronous ConnectableObservable.connect problem
Pull 1172 ObserveOn: Change to batch dequeue
Pull 1191 Fix attempt for OperatorPivotTest
Pull 1195 SwingScheduler: allow negative schedule
Pull 1178 Fix RxScala bug
Pull 1210 Add more operators to RxScala
Pull 1216 RxScala: Exposing PublishSubject
Pull 1208 OperatorToObservableList: use LinkedList to buffer the sequence’s items
Pull 1185 Behavior subject time gap fix 2
Pull 1226 Fix bug in zipWithIndex and set zip(that, selector) public in RxScala
Pull 1224 Implement shorter toBlocking as shorter alias for toBlockingObservable.
Pull 1223 ReplaySubject enhancement with time and/or size bounds
Pull 1160 Add replay and multicast variants to RxScala
Pull 1229 Remove Ambiguous Subscribe Overloads with Scheduler
Pull 1232 Adopt Limit and ForEach Java 8 Naming Conventions
Pull 1233 Deprecate toBlockingObservable in favor of toBlocking
Pull 1237 SafeSubscriber memory reduction
Pull 1236 CompositeSubscription with atomic field updater
Pull 1243 Remove Subscription Wrapper from Observable.subscribe
Pull 1244 Observable.from(T) using Observable.just(T)
Pull 1239 RxScala: Update docs for "apply" and add an example
Pull 1248 Fixed testConcurrentOnNextFailsValidation
Pull 1246 Moved to atomic field updaters.
Pull 1254 ZipIterable unsubscription fix
Pull 1247 Add zip(iterable, selector) to RxScala
Pull 1260 Fix the bug that BlockingObservable.singleOrDefault doesn't call unsubscribe
Pull 1269 Fix the bug that int overflow can bypass the range check
Pull 1272 ExecutorScheduler to wrap an Executor
Pull 1264 ObserveOn scheduled unsubscription
Pull 1271 Operator Retry with predicate
Pull 1265 Add more operators to RxScala
Pull 1281 Reduce Subscription Object Allocation
Pull 1284 Lock-free, MPSC-queue
Pull 1288 Ensure StringObservable.from() does not perform unnecessary read
Pull 1286 Rename some Operator* classes to OnSubscribe*
Pull 1276 CachedThreadScheduler
Pull 1287 ReplaySubject remove replayState CHM and related SubjectObserver changes
Pull 1289 Schedulers.from(Executor)
Pull 1290 Upgrade to JMH 0.7.3
Pull 1293 Fix and Update JMH Perf Tests
Pull 1291 Check unsubscribe within observable from future
Pull 1294 rx.operators -> rx.internal.operators
Pull 1295 Change void accept to boolean accept
Pull 1296 Move re-used internal Scheduler classes to their own package
Pull 1298 Remove Bad Perf Test
Pull 1301 RxScala: Add convenience method for adding unsubscription callback
Pull 1304 Add flatMap and concatMap to RxScala
Pull 1306 Hooked RxJavaPlugins errorHandler up within all operators that swallow onErrors
Pull 1309 Hide ChainedSubscription/SubscriptionList from Public API

Artifacts: Maven Central

Assets 2

29 May 23:05

benjchristensen

0.18.4

c14f2b7

0.18.4

This is a fix for CompositeSubscription object allocation problems. Details can be found in issue #1204.

Pull 1283 Subscription object allocation fix

Artifacts: Maven Central

Assets 2

09 May 17:57

benjchristensen

0.18.3

2e0e537

0.18.3

Pull 1161 Removed use of deprecated API from tests & operators
Pull 1162 fix to remove drift from schedulePeriodic
Pull 1159 Rxscala improvement
Pull 1164 JMH Perf Tests for Schedulers.computation
Pull 1158 Scheduler correctness improvements.

Artifacts: Maven Central

Assets 2

05 May 21:13

benjchristensen

0.18.2

8273d60

0.18.2

Continued work on migrating operators on path to 1.0 along with various bug fixes.

Pull 1150 Fix ReplaySubject Terminal State Race Condition
Pull 1144 Operator Delay rebase & fixes
Pull 1142 Update 'contains' signature to 'contains(Object)'
Pull 1134 OperatorTakeLast
Pull 1135 OperatorTakeUntil
Pull 1137 Random fixes to operators multicast, sample, refCount
Pull 1138 Operator Window and other changes
Pull 1131 Operator TakeTimed
Pull 1130 Operator Switch
Pull 1129 Conditional statements contribution to Operator
Pull 1128 Fix for SerializedObserverTest
Pull 1126 Operator When
Pull 1125 Operator contrib math
Pull 1124 Add lift to rxscala
Pull 1122 OperatorSkipUntil
Pull 1121 OperatorSkipTimed
Pull 1120 OperatorSequenceEqual
Pull 1119 OperatorRefCount
Pull 1118 Operator ParallelMerge
Pull 1117 Operator OnExceptionResumeNextViaObservable
Pull 1115 OperatorTakeWhile
Pull 1112 OperatorThrottleFirst
Pull 1111 OperatorTimeInterval
Pull 1110 OperatorOnErrorReturn
Pull 1109 OperatorOnErrorResumeNextViaObservable
Pull 1108 OperatorMulticastAndReplay
Pull 1107 Fix ReplaySubject's double termination problem.
Pull 1106 OperatorMergeMaxConcurrent
Pull 1104 Operator merge delay error
Pull 1103 OperatorJoin
Pull 1101 Operator async
Pull 1100 OperatorUsing
Pull 1099 OperatorToMap
Pull 1098 OperatorTimerAndSample
Pull 1097 OperatorToMultimap
Pull 1096 OperatorGroupJoin
Pull 1095 OperatorGroupByUntil
Pull 1094 Operator debounce

Artifacts: Maven Central

Assets 2

25 Apr 03:27

benjchristensen

0.18.1

5f17435

0.18.1

Pull 1065 Optimize OperatorSkipLastTimed
Pull 1073 OperatorBuffer
Pull 1074 OperatorConcat
Pull 1088 OperatorToObservableFuture
Pull 1087 OperatorMergeMap
Pull 1086 OperatorFinallyDo
Pull 1085 OperatorDistinctUntilChanged
Pull 1084 OperatorDistinct
Pull 1083 OperatorDematerialize
Pull 1081 OperatorDefer
Pull 1080 OperatorDefaultIfEmpty
Pull 1079 OperatorCombineLatest
Pull 1074 OperatorConcat
Pull 1073 OperatorBuffer
Pull 1091 Handle Thrown Errors with UnsafeSubscribe
Pull 1092 Restore ObservableExecutionHook.onCreate

Artifacts: Maven Central

Assets 2

23 Apr 05:16

benjchristensen

0.18.0

27c64f4

0.18.0

This release takes us a step closer to 1.0 by completing some of the remaining work on the roadmap.

Scheduler

The first is simplifying the Scheduler API.

The Scheduler API is now simplified to this:

class Scheduler {
    public abstract Worker createWorker(); 
    public int parallelism();
    public long now();

    public abstract static class Worker implements Subscription {
        public abstract Subscription schedule(Action0 action, long delayTime, TimeUnit unit);
        public abstract Subscription schedule(Action0 action);
        public Subscription schedulePeriodically(Action0 action, long initialDelay, long period, TimeUnit unit);
        public long now();
    }
}

This is a breaking change if you have a custom Scheduler implementation or use a Scheduler directly. If you only ever pass in a Scheduler via the Schedulers factory methods, this change does not affect you.

Additionally, the ExecutionScheduler was removed because a general threadpool does not meet the requirements of sequential execution for an Observable. It was replaced with rx.schedulers.EventLoopScheduler which is the new default for Schedulers.computation(). It is a pool of event loops.

rx.joins

The rx.joins package and associated when, and and then operators were moved out of rxjava-core into a new module rxjava-joins. This is done as the rx.joins API was not yet matured and is not going to happen before 1.0. It was determined low priority and not worth blocking a 1.0 release. If the API matures inside the separate module to the point where it makes sense to bring it back into the core it can be done in the 1.x series.

Deprecation Cleanup

This releases removes many of the classes and methods that have been deprecated in previous releases. Most of the removed functionality was migrated in previous releases to contrib modules such as rxjava-math, rxjava-async and rxjava-computation-expressions.

A handful of deprecated items still remain but can not yet be removed until all internal operators are finished migrating to using the lift/Subscriber design changes done in 0.17.0.

The full list of changes in 0.18.0: