PartialFunction問題

simple/src/main/main.iml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/scala" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

simple/src/main/scala/com/github/tanacasino/study/nabedge/Area.scala

@@ -0,0 +1,19 @@
+package com.github.tanacasino.study.nabedge
+
+object 
+Area extends App {
+
+  // area関数は引数として円周率を受け取り、その円周率を使って面積を求める関数を返す。その関数は半径を受け取る
+
+  val f1 = area(3.14)
+  println(f1(10)) // 314.0
+  println(f1(1)) // 3.14
+  val f2 = area(3)
+  println(f2(10)) // 300
+  println(f2(1)) // 3
+
+  def area(pi: Double): (Double) => Double = {
+    (r: Double) => r * r * pi
+  }
+
+}

simple/src/main/scala/com/github/tanacasino/study/nabedge/Func.scala

@@ -0,0 +1,42 @@
+package com.github.tanacasino.study.nabedge
+
+import scala.util.Try
+
+object Func extends App {
+
+  //関数の合成
+  def functionCompose() = {
+    val f = (x: Int) => x + 1
+    val g = (x: Int) => x * 3
+    val h1 = f compose g
+    val h2 = g andThen f
+    assert(h1(10) == 31)
+    assert(h2(10) == 31)
+  }
+  functionCompose()
+
+
+  //任意の数の関数を受け取り
+  //それらを順に適用する関数を返す関数
+  def chainFunction(funcs: Function[Int,Int]*) = {
+    funcs.reduceLeft(_ andThen _)
+  }
+  val f1 = (x: Int) => { x + 1 }
+  val f2 = (x: Int) => { x * 2 }
+  val f3 = (x: Int) => { x - 1 }
+  val f4 = chainFunction(f1, f2, f3)
+  println(f4(10)) // => 21 ならok
+
+  /*
+  Seq[String]とPartialFunctionを受け取り、
+  各要素に対してPartialFunctionにマッチした場合はその戻り値、
+  マッチしない場合は元の要素を格納したSeqを返す関数（以下の例のreplace関数）を作ってみよう。
+   */
+  def replace(langs: Seq[String], pf: PartialFunction[String,String]) = {
+//    langs.map{ lang => Try(pf(lang)).getOrElse(lang) }.toSeq
+//    langs.map{ lang => if (pf.isDefinedAt(lang)) pf(lang) else lang}.toSeq
+  }
+  val langs = Seq("Java", "JavaScript", "Scala")
+  val result = replace(langs, { case "Scala" => "Cool" })
+  println(result) // => Seq(Java, JavaScript, Cool)になったらOK!
+}

simple/src/main/scala/com/github/tanacasino/study/nabedge/FutureMain.scala

@@ -0,0 +1,49 @@
+package com.github.tanacasino.study.nabedge
+
+import scala.concurrent.Future
+import scala.concurrent.ExecutionContext.Implicits.global
+import scala.util.{Failure, Success}
+
+object FutureMain extends FutureTrait {
+
+  def main(args: Array[String]): Unit = {
+//    future2()
+    drill01()
+  }
+
+}
+
+trait FutureTrait {
+
+  // ただのスリープ
+  def future1() = {
+    println("Start")
+    Thread.sleep(5000)
+    println("end")
+  }
+
+  // Futureによる非同期計算
+  def future2() = {
+    println("Start")
+    val f = Future {
+      Thread.sleep(5000)
+      println("Future!!!")
+    }
+    println("end")
+    Thread.sleep(6000)
+  }
+
+  def drill01() = {
+    val f1 = Future("Hello").map(_.size)
+    f1.onComplete{
+      case Success(h) => println(s"f1 success $h")
+      case Failure(e) => println(s"f1 failed: e")
+    }
+    Thread.sleep(5000)
+    println("*** drill01 END ***")
+//    val newFuture = Future("new future")
+//    val f2 = Future("Helloaa").filter(_.size < 5).recoverWith{
+//      case e: NoSuchElementException => newFuture
+//    }
+  }
+}

simple/src/main/scala/com/github/tanacasino/study/nabedge/FutureSample.scala

@@ -0,0 +1,34 @@
+package com.github.tanacasino.study.nabedge
+
+import scala.concurrent.ExecutionContext.Implicits.global
+
+import scala.concurrent.Future
+
+/*
+以下のような集計処理を行うメソッドがあるとします。
+def aggregate(id: String): Int ={
+...
+}
+このメソッドを使って特定のIDに対する集計結果の合計を求めるコードがあります。
+val result = Seq("rikunabi", "mynavi", "en").map { id => aggregate(id) }.sum
+ただし、aggregateメソッドは実行に時間がかかるので並列化したいと思います。Futureを使って書き直してみましょう。
+
+ */
+object FutureSample {
+
+  def aggregate(id: String): Int ={
+    Thread.sleep(100) // なんか重い処理
+    id.size
+  }
+
+  def main(args: Array[String]): Unit = {
+//    val result = Seq("rikunabi", "mynavi", "en").map { id => aggregate(id) }.sum
+//    println(result)
+    val result2 = Seq("rikunabi", "mynavi", "en").map(id => Future(aggregate(id)))
+    val f = Future.reduce(result2)(_ + _)
+    f.foreach(println)
+    Thread.sleep(1000)
+//    println(result2)
+  }
+}
+

simple/src/main/scala/com/github/tanacasino/study/nabedge/Timeit.scala

@@ -0,0 +1,39 @@
+package com.github.tanacasino.study.nabedge
+
+object Timeit extends App {
+
+  def timeIt[A](f:() => A):A = {
+    val start: Long = System.currentTimeMillis()
+    println(s"start $start")
+    val result = f()
+    val end: Long = System.currentTimeMillis()
+    val time = end - start
+    println(s"end $end")
+    println(s"time $time")
+    result
+  }
+
+  timeIt ({ () =>
+    Thread.sleep(100)
+    println("Hello, World !")
+  })
+
+  /* 
+// 実行結果が以下のようになる timeit 関数を作ってみよう
+//引数にて関数を受け取ればよいのです！
+  timeit {
+ Thread.sleep(100)
+ println("Hello, World!")
+}
+
+"""
+start: 12345677890
+Hello, World!
+end: 12345678100
+time: 101
+"""
+
+   */
+
+
+}

simple/src/main/scala/com/github/tanacasino/study/tanacasino/future/Future1.scala

@@ -3,7 +3,7 @@ package com.github.tanacasino.study.tanacasino.future
 
 import scala.concurrent.ExecutionContext.Implicits.global
 import scala.concurrent.duration.Duration
-import scala.concurrent.{Await, Future}
+import scala.concurrent.{ExecutionContext, Await, Future}
 import scala.util.{Failure, Success}
 
 
@@ -37,7 +37,11 @@ trait Future1 {
   // Futureによる非同期計算
   def future2() = {
     println("Start")
-
+//    object MyObject {
+//      def apply[T](f: => T)(implicit val ec: ExecutionContext): T = {
+//        f
+//      }
+//    }
     val f = Future {
       Thread.sleep(5000)
       println("Future!!!")

simple/src/test/test.iml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/scala" isTestSource="true" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>