[英]scalaz-stream consume stream based on computed value
I've got two streams and I want to be able to consume only one based on a computation that I run every x
seconds. 我有两个流,并且我希望只能基于每
x
秒运行一次的计算消耗一个流。
I think I basically need to create a third tick
stream - something like every(3.seconds)
- that does the computation and then come up with sort of a switch between the other two. 我想我基本上需要创建第三个
tick
流-像every(3.seconds)
-进行计算,然后在其他两个之间进行切换。
I'm kind of stuck here (and I've only just started fooling around with scalaz-stream). 我有点被困在这里(我只是刚刚开始使用scalaz-stream来开玩笑)。
Thanks! 谢谢!
There are several ways we can approach this problem. 有几种方法可以解决此问题。 One way to approach it is using
awakeEvery
. 一种解决方法是使用
awakeEvery
。 For concrete example, see here . 有关具体示例,请参见此处 。
To describe the example briefly, consider that we would like to query twitter in every 5 sec and get the tweets and perform sentiment analysis. 为了简短地描述示例,请考虑我们希望每5秒查询一次Twitter,并获取推文并进行情感分析。 We can compose this pipeline as follows:
我们可以如下组成该管道:
val source =
awakeEvery(5 seconds) |> buildTwitterQuery(query) through queryChannel flatMap {
Process emitAll _
}
Note that the queryChannel
can be stated as follows. 注意,
queryChannel
可以表示如下。
def statusTask(query: Query): Task[List[Status]] = Task {
twitterClient.search(query).getTweets.toList
}
val queryChannel: Channel[Task, Query, List[Status]] = channel lift statusTask
Let me know if you have any question. 如果您有任何问题,请告诉我。 As stated earlier, for the complete example, see this .
如前所述,有关完整示例,请参见this 。
I hope it helps! 希望对您有所帮助!
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