Merge pull request #6 from Mironor/master

Added solutions for chapter 1, exercise 1 to 5 and chapter 2 exercise 1 to 3

Author: axel22

src/main/scala/org/learningconcurrency/exercises/ch1.scala

@@ -0,0 +1,25 @@
+package org.learningconcurrency.exercises
+
+object CH1Solutions extends App{
+
+  def compose[A, B, C](g: B => C, f: A => B): A => C = g compose f
+  // Alternative solutioin:                          = x => g(f(x))
+
+  def fuse[A, B](a: Option[A], b: Option[B]): Option[(A, B)] = for {
+    aVal <- a
+    bVal <- b
+  } yield (aVal, bVal)
+
+  def check2[T](xs: Seq[T])(pred: T => Boolean): Boolean = xs.forall {x => 
+    try {
+      pred(x)
+    } catch { 
+      case _: Exception => false
+    }
+  )
+
+  def permutations(x: String): Seq[String] = x.permutations.toList
+    
+}
+
+case class Pair[P, Q](first: P, second: Q)

src/main/scala/org/learningconcurrency/exercises/ch2.scala

@@ -0,0 +1,42 @@
+package org.learningconcurrency.exercises
+
+import org.learningconcurrency.ch2.thread
+
+
+object CH2Solutions extends App{
+
+  def parallel[A, B](a: =>A, b: =>B): (A, B) = {
+    var aVal: A = null.asInstanceOf[A]
+    var bVal: B = null.asInstanceOf[B] 
+    
+    val t1 = thread {
+      aVal = a
+      log(aVal.toString())
+    }
+
+    val t2 = thread {
+      bVal = b
+      log(bVal.toString())
+    }
+
+    t1.join()
+    t2.join()
+
+    (aVal, bVal)
+  }
+
+  def periodically(duration: Long)(f: () => Unit): Unit = {
+      val worker = new Thread {
+        while(true){
+          f()
+          Thread.sleep(duration)
+        }
+      }
+
+      worker.setName("Worker")
+      worker.setDaemon(true)
+      worker.start()
+    }
+  }
+
+}

src/main/scala/org/learningconcurrency/exercises/package.scala

@@ -1,10 +1,5 @@
 package org.learningconcurrency
 
 
-
-
-
-
 package object exercises {
-
 }