Spring I/O 2018 でお話があった以下のセッションについて自分なりにまとめてみました。
- Flight of the Flux
https://speakerdeck.com/simonbasle/flight-of-the-flux
- Under the hood of Reactive Data Access
https://speakerdeck.com/mp911de/under-the-hood-of-reactive-data-access-1
- REST beyond the obvious
https://speakerdeck.com/olivergierke/rest-beyond-the-obvious-api-design-for-ever-evolving-systems
JavaOne 2016 Java SE Feedback #jjug #j1jpYuji Kubota
Slide for reporting Java SE Feedback of JavaOne 2016 at Japan Java User Group. Especially, this slide introduces the changes required for Java 9.
https://jjug.doorkeeper.jp/events/52639
JavaOne 2016 Java SE Feedback #jjug #j1jpYuji Kubota
Slide for reporting Java SE Feedback of JavaOne 2016 at Japan Java User Group. Especially, this slide introduces the changes required for Java 9.
https://jjug.doorkeeper.jp/events/52639
【DLゼミ】XFeat: Accelerated Features for Lightweight Image Matchingharmonylab
公開URL:https://arxiv.org/pdf/2404.19174
出典:Guilherme Potje, Felipe Cadar, Andre Araujo, Renato Martins, Erickson R. ascimento: XFeat: Accelerated Features for Lightweight Image Matching, Proceedings of the 2024 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) (2023)
概要:リソース効率に優れた特徴点マッチングのための軽量なアーキテクチャ「XFeat(Accelerated Features)」を提案します。手法は、局所的な特徴点の検出、抽出、マッチングのための畳み込みニューラルネットワークの基本的な設計を再検討します。特に、リソースが限られたデバイス向けに迅速かつ堅牢なアルゴリズムが必要とされるため、解像度を可能な限り高く保ちながら、ネットワークのチャネル数を制限します。さらに、スパース下でのマッチングを選択できる設計となっており、ナビゲーションやARなどのアプリケーションに適しています。XFeatは、高速かつ同等以上の精度を実現し、一般的なラップトップのCPU上でリアルタイムで動作します。
セル生産方式におけるロボットの活用には様々な問題があるが,その一つとして 3 体以上の物体の組み立てが挙げられる.一般に,複数物体を同時に組み立てる際は,対象の部品をそれぞれロボットアームまたは治具でそれぞれ独立に保持することで組み立てを遂行すると考えられる.ただし,この方法ではロボットアームや治具を部品数と同じ数だけ必要とし,部品数が多いほどコスト面や設置スペースの関係で無駄が多くなる.この課題に対して音𣷓らは組み立て対象物に働く接触力等の解析により,治具等で固定されていない対象物が組み立て作業中に運動しにくい状態となる条件を求めた.すなわち,環境中の非把持対象物のロバスト性を考慮して,組み立て作業条件を検討している.本研究ではこの方策に基づいて,複数物体の組み立て作業を単腕マニピュレータで実行することを目的とする.このとき,対象物のロバスト性を考慮することで,仮組状態の複数物体を同時に扱う手法を提案する.作業対象としてパイプジョイントの組み立てを挙げ,簡易な道具を用いることで単腕マニピュレータで複数物体を同時に把持できることを示す.さらに,作業成功率の向上のために RGB-D カメラを用いた物体の位置検出に基づくロボット制御及び動作計画を実装する.
This paper discusses assembly operations using a single manipulator and a parallel gripper to simultaneously
grasp multiple objects and hold the group of temporarily assembled objects. Multiple robots and jigs generally operate
assembly tasks by constraining the target objects mechanically or geometrically to prevent them from moving. It is
necessary to analyze the physical interaction between the objects for such constraints to achieve the tasks with a single
gripper. In this paper, we focus on assembling pipe joints as an example and discuss constraining the motion of the
objects. Our demonstration shows that a simple tool can facilitate holding multiple objects with a single gripper.
11. Flight of the Flux: A look at Reactor execution model
Nothing happens until you subscribe
Assembly & Execution Time
Debug
Hot&Cold Publisher(例例外)
Concurrency Agnosticだけどスレッドを使う
publishOn&subscribeOn
work stealing
その他のよしなに系処理理
macro & micro fusion
!11
26. Assembly Time / Execution Time はタイミングが違う
java.lang.IndexOutOfBoundsException: Source emitted more than one item
at reactor.core.publisher.MonoSingle$SingleSubscriber.onNext(MonoSingle.java:129)
at reactor.core.publisher.FluxFlatMap$FlatMapMain.tryEmitScalar(FluxFlatMap.java:445)
at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:379)
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:121)
at reactor.core.publisher.FluxRange$RangeSubscription.slowPath(FluxRange.java:154)
at reactor.core.publisher.FluxRange$RangeSubscription.request(FluxRange.java:109)
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:162)
at reactor.core.publisher.FluxFlatMap$FlatMapMain.onSubscribe(FluxFlatMap.java:332)
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onSubscribe(FluxMapFuseable.java:
90)
at reactor.core.publisher.FluxRange.subscribe(FluxRange.java:68)
at reactor.core.publisher.FluxMapFuseable.subscribe(FluxMapFuseable.java:63)
at reactor.core.publisher.FluxFlatMap.subscribe(FluxFlatMap.java:97)
at reactor.core.publisher.MonoSingle.subscribe(MonoSingle.java:58)
at reactor.core.publisher.Mono.subscribe(Mono.java:3096)
at reactor.core.publisher.Mono.subscribeWith(Mono.java:3204)
at reactor.core.publisher.Mono.subscribe(Mono.java:3090)
at reactor.core.publisher.Mono.subscribe(Mono.java:3057)
at reactor.core.publisher.Mono.subscribe(Mono.java:3029)
at reactor.guide.GuideTests.debuggingCommonStacktrace(GuideTests.java:995)
→ stacktraceが追いづらい
!26
27. Hooks.onOperatorDebug();
Assembly timeの機構を利利⽤用
アプリ起動時(Flux,Monoのインスタンス
化前)に⾏行行われる
java.lang.IndexOutOfBoundsException: Source emitted more than one item
at reactor.core.publisher.MonoSingle$SingleSubscriber.onNext(MonoSingle.java:120)
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:314)
...
...
at reactor.core.publisher.Mono.subscribeWith(Mono.java:2668)
at reactor.core.publisher.Mono.subscribe(Mono.java:2629)
at reactor.core.publisher.Mono.subscribe(Mono.java:2604)
at reactor.core.publisher.Mono.subscribe(Mono.java:2582)
at reactor.guide.GuideTests.debuggingActivated(GuideTests.java:727)
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Assembly trace from producer [reactor.core.publisher.MonoSingle] :
reactor.core.publisher.Flux.single(Flux.java:5335)
reactor.guide.GuideTests.scatterAndGather(GuideTests.java:689)
reactor.guide.GuideTests.populateDebug(GuideTests.java:702)
org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55)
org.junit.rules.RunRules.evaluate(RunRules.java:20)
Error has been observed by the following operator(s):
|_ Flux.single(TestWatcher.java:55)
Debugモードにする魔法
エラーが起きるとFluxがnewされた箇所を
Assembly Timeに解析した内容を元に
追記してくれる
(がコストが⾼高い)!27
28. checkpoint()
Debugの仕⽅方2
!28
public void checkpointWithDescriptionIsLight() {
StringWriter sw = new StringWriter();
Flux<Integer> tested = Flux.range(1, 10)
.map(i -> i < 3 ? i : null)
.filter(i -> i % 2 == 0)
.checkpoint("foo")
.doOnError(t -> t.printStackTrace(new PrintWriter(sw)));
StepVerifier.create(tested)
.expectNext(2)
.verifyError();
String debugStack = sw.toString();
}
Assembly site of producer [reactor.core.publisher.FluxFilterFuseable] is
identified by light checkpoint [foo].
29. Nothing happens until you subscribe… ですが 例例外あり
Hot Publisher
Cold Publisher
これはこっちの話
subscriptionごとにデータを新しくこさえる
例例:HTTP request
⼀一度でもsubscribeされたら(⼀一度データが流れ出したら)
その後はお構いなく流れていく
途中からsubscribeしたSubscriberはsubscribeするより前に
何かが起こっていることになる
例例:Processorクラスを継承したもの
!29
31. Flux<String> source = Flux.fromIterable(Arrays.asList("blue", "green", "orange", "purple"))
.map(String::toUpperCase);
source.subscribe(d -> System.out.println("Subscriber 1 to Cold Source: "+d));
source.subscribe(d -> System.out.println("Subscriber 2 to Cold Source: "+d));
Subscriber 1 to Cold Source: BLUE
Subscriber 1 to Cold Source: GREEN
Subscriber 1 to Cold Source: ORANGE
Subscriber 1 to Cold Source: PURPLE
Subscriber 2 to Cold Source: BLUE
Subscriber 2 to Cold Source: GREEN
Subscriber 2 to Cold Source: ORANGE
Subscriber 2 to Cold Source: PURPLE
Cold Publisher
!31
32. UnicastProcessor<String> hotSource = UnicastProcessor.create();
Flux<String> hotFlux = hotSource.publish()
.autoConnect()
.map(String::toUpperCase);
hotSource.onNext("blue");
hotSource.onNext("green");
hotFlux.subscribe(d -> System.out.println("Subscriber 1 to Hot Source: "+d));
hotFlux.subscribe(d -> System.out.println("Subscriber 2 to Hot Source: "+d));
hotSource.onNext("orange");
hotFlux.subscribe(d -> System.out.println("Subscriber 3 to Hot Source: "+d));
hotSource.onNext("purple");
hotSource.onComplete();
Hot Publisher
!32
33. Subscriber 1 to Hot Source: BLUE
Subscriber 1 to Hot Source: GREEN
Subscriber 1 to Hot Source: ORANGE
Subscriber 2 to Hot Source: ORANGE
Subscriber 1 to Hot Source: PURPLE
Subscriber 2 to Hot Source: PURPLE
Subscriber 3 to Hot Source: PURPLE
Hot Publisher
UnicastProcessor<String> hotSource = UnicastProcessor.create();
Flux<String> hotFlux = hotSource.publish()
.autoConnect()
.map(String::toUpperCase);
hotSource.onNext("blue");
hotSource.onNext("green");
hotFlux.subscribe(d -> System.out.println("Subscriber 1 to Hot Source: "+d));
hotFlux.subscribe(d -> System.out.println("Subscriber 2 to Hot Source: "+d));
hotSource.onNext("orange");
hotFlux.subscribe(d -> System.out.println("Subscriber 3 to Hot Source: "+d));
hotSource.onNext("purple");
hotSource.onComplete();
!33
45. Spring Data で Reactive に DB アクセスできるもの
•Spring Data Commons
•Spring Data JPA
•Spring Data KeyValue
•Spring Data LDAP
•Spring Data MongoDB
•Spring Data REST
•Spring Data Redis
•Spring Data for Apache Cassandra
•Spring Data for Apache Geode
•Spring Data for Apache Solr
•Spring Data for Pivotal GemFire
•Spring Data Couchbase (community module)
•Spring Data Elasticsearch (community module)
•Spring Data Neo4j (community module)
http://projects.spring.io/spring-data/
ドキュメント指向
Key-Value型
Column型
KVS
!45
アクションログ
46. Spring Data
JDBC
JVM
RDBS
Reactor
MongoDB
Reactive Streams
Java Driver
JVM
MongoDB
Reactor
Lettuce
JVM
Redis
Reactor
DataStax Java driver
for Cassandra
JVM
Cassandra
Reactor
Reactive
Couchbase
JVM
Couchbase
Server
Spring Data JPA
Spring Data
MongoDB
Spring Data
Redis
Spring Data for
Cassandra
Spring Data
Couchbase
Under the hood of ~の話のスコープ
… 各ベンダが⽤用意している DB Driver の Reactive 対応状況
!46
47. Spring Data
JDBC
JVM
RDBS
Reactor
MongoDB
Reactive Streams
Java Driver
JVM
MongoDB
Reactor
Lettuce
JVM
Redis
Reactor
DataStax Java driver
for Cassandra
JVM
Cassandra
Reactor
Reactive
Couchbase
JVM
Couchbase
Server
Spring Data JPA
Spring Data
MongoDB
Spring Data
Redis
Spring Data for
Cassandra
Spring Data
Couchbase
Under the hood of ~の話のスコープ
… 各ベンダが⽤用意している DB Driver の Reactive 対応状況
Fully blocking API
ADBA,R2DBCなどがnon-blocking api
!47