本文整理汇总了Scala中scala.collection.immutable.Stream类的典型用法代码示例。如果您正苦于以下问题：Scala Stream类的具体用法？Scala Stream怎么用？Scala Stream使用的例子？那么恭喜您, 这里精选的类代码示例或许可以为您提供帮助。
在下文中一共展示了Stream类的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Scala代码示例。
示例1: BlockCheckpoint
//设置package包名称以及导入依赖的类
package com.wavesplatform.network
import com.google.common.primitives.{Bytes, Ints}
import io.swagger.annotations.ApiModelProperty
import play.api.libs.json._
import scorex.crypto.encode.Base58
import scala.collection.immutable.Stream
import scala.util.{Failure, Success}
case class BlockCheckpoint(height: Int,
@ApiModelProperty(dataType = "java.lang.String") signature: Array[Byte])
case class Checkpoint(items: Seq[BlockCheckpoint],
@ApiModelProperty(dataType = "java.lang.String")signature: Array[Byte]) {
def toSign: Array[Byte] = {
val length = items.size
val lengthBytes = Ints.toByteArray(length)
items.foldLeft(lengthBytes) { case (bs, BlockCheckpoint(h, s)) =>
Bytes.concat(bs, Ints.toByteArray(h), s)
}
}
}
object Checkpoint {
def historyPoints(n: Int, maxRollback: Int, resultSize: Int = MaxCheckpoints): Seq[Int] =
mult(maxRollback, 2).map(n - _).takeWhile(_ > 0).take(resultSize)
private def mult(start: Int, step: Int): Stream[Int] =
Stream.cons(start, mult(start * step, step))
val MaxCheckpoints = 10
implicit val byteArrayReads = new Reads[Array[Byte]] {
def reads(json: JsValue) = json match {
case JsString(s) => Base58.decode(s) match {
case Success(bytes) if bytes.length == scorex.transaction.TransactionParser.SignatureLength => JsSuccess(bytes)
case Success(bytes) => JsError(JsonValidationError("error.incorrect.signatureLength", bytes.length.toString))
case Failure(t) => JsError(JsonValidationError(Seq("error.incorrect.base58", t.getLocalizedMessage), s))
}
case _ => JsError("error.expected.jsstring")
}
}
implicit val blockCheckpointFormat: Reads[BlockCheckpoint] = Json.reads
implicit val checkpointFormat: Reads[Checkpoint] = Json.reads
} 示例2: Numbers
//设置package包名称以及导入依赖的类
import scala.collection.immutable.Stream
object Numbers {
private lazy val N: Stream[BigInt] = BigInt(1) #:: N.map(_ + BigInt(1))
def binomialCoef(n: Int, k: Int): Option[Long] = {
type Cache = Map[(Int, Int), Long]
def memoizedBinCoef(ni: Int, ki: Int)(cache: Cache): (Long, Cache) =
if(ni == ki) 1L -> cache
else if(ki == 1) ni.toLong -> cache
else cache.get(ni -> ki).map(_ -> cache) getOrElse {
val (a, aCache) = memoizedBinCoef(ni-1, ki-1)(cache)
val (b, bCache) = memoizedBinCoef(ni-1, ki)(aCache)
(a+b, bCache.updated(ni -> ki, a+b))
}
if(n < 1 || k < 1 || n < k) None
else Some(memoizedBinCoef(n,k)(Map.empty)._1)
}
}