reactive

问题 I want to take 3 last elements from an observable. Let's say that my timeline looks like this: --a---b-c---d---e---f-g-h-i------j-> where: a, b, c, d, e, f, g, h, i, j are emitted values Whenever a new value is emitted I want to get it immediately, so it can look like this: [a] [a, b] [a, b, c] [b, c, d] [c, d, e] [d, e, f] [e, f, g] [f, g, h] ... and so on I think that this is super useful. Imagine building a chat where you want to display 10 last messages. Whenever a new message comes you

问题 This is the code for producing a single message to Kafka given in the doc https://doc.akka.io/docs/alpakka-kafka/current/producer.html val single: ProducerMessage.Envelope[KeyType, ValueType, PassThroughType] = ProducerMessage.single( new ProducerRecord("topicName", key, value), passThrough ) Could you please explain what is passThrough used for? 回答1: passThrough is an additional value which comes to be available for use in ProducerMessage.Results ’s passThrough() . As the official

问题 I am trying to use plotOutput in R shiny in multiple sub-menu items. However, I believe it is not possible for plotOutput to be used at multiple places with same id. Please help me if it is possible somehow. attaching the snapshot for reference. library(shiny) library(shinydashboard) ui <- dashboardPage( dashboardHeader(), dashboardSidebar( sidebarMenu( id = "tabs", menuItem("Charts", icon = icon("bar-chart-o"), menuSubItem("Sub-item 1", tabName = "subitem1"), menuSubItem("Sub-item 2",

问题 I have a reactive core WebClient to post to a given endpoint. The payload is a flux of Job objects and the content-type is application/stream+json Flux jobFlux = Flux.just(new Job()); Mono<JsonNode> response = localEP.post().uri( "/dev/job" ) .contentType(MediaType.APPLICATION_STREAM_JSON) .body( BodyInserters.fromObject(jobFlux)) .retrieve() .bodyToMono( JsonNode.class ); On the server end I have tried both a Spring Controller style and Spring Web Reactive FunctionHandler to process the

问题 Seems like pipe doesn't work with reactive form control valueChanges. i've prepared this https://stackblitz.com/edit/angular-vdeqrz so that you can reproduce the problem. type something in the text field. then type "boom" (without the quotes). after the error catch, the control does not work any more. you can verify typing something new on it after that. it does not detect any other input. if you refresh the page, then it works again. am i missing something here ? 回答1: This is not a bug.

问题 I am trying to understand hotObservables and have written this example but it doesn't seem to emitting anything. ConnectableObservable<Long> cold = Observable.intervalRange(1, 20, 100, 100, TimeUnit.MICROSECONDS).publish(); cold.subscribe(i -> System.out.println("First: " + i)); cold.connect(); Moving the cold.connect() to just after creating the ConnectableObservable doesn't changes anything. 来源： https://stackoverflow.com/questions/46991778/connectableobservable-not-emitting-values

问题 I have a Shiny dashboard that is displaying a sankeyNetwork from the networkD3 package. I'm creating the sankeyNetwork inside of a renderSankeyNetwork function on the server and then calling it on the ui with sankeyNetworkOutput. I'd like to make the height of the created sankeynetwork be dependent on a height value I've created. I tried using renderUI with uiOutput to run the sankeyNetworkOutput on the server, but it doesn't seem to be working. The dashboard works otherwise but there is

问题 I have a problem at work. I am building a Shiny app and trying to subset data based on the value of three selection boxes. My data has three variables, Commissioner, Neighbourhood and Practice. What I need is that no matter which box the user chooses first to filter the data on, the other two update to only show relevant choices. The default on loading is to show all choices in all boxes. I've made a start but getting no where fast. The code below shows all the choices in Commissioner on

问题 I would like to make a shinyapp that integrates the functionality of choosing a file (in a selected folder), (like in Interactive directory input in Shiny app (R)), and then reading it reactively by detecting changes in it, as in https://gist.github.com/wch/9652222. However, I could not make the reactiveFileReader function work with a reactive filename (folder). It seems to work only with one pre-determined filename. In this app, the file is expected to be chosen automatically after chosing

问题 I am new to shiny but kind of like it. Now I have an interesting question in needing of help. I have a database can be queried by either indexA and indexB, but not both. That is if I use selectInput to retrieve data from one index(for example, indexA), I have to set another index(in this case, indexB) to default value(B0), and vise versa. The output widget is depends on both selectInput. Hence, if I interact one selectInput to query data, I need to update another selectInput, which will cause