apply Method

methods as Infix Operators

Author: CodeLab20

Methods/EmployeeDesignWithApply.scala

@@ -0,0 +1,39 @@
+import java.time._
+
+class Employee protected(val firstName:String, val lastName: String, val title:String, val hireDate:LocalDate)
+
+object Employee
+{
+    def apply(firstName:String, lastName:String, title:String) = 
+        new Employee(firstName, lastName, title, LocalDate.now)
+    
+    
+    //if a method name is "apply", you dont have to explicitly call it.
+    //apply can be used in classes and objects
+    def apply(firstName:String, lastName:String, title:String, hireDate:LocalDate) = 
+        new Employee(firstName, lastName, title, hireDate)
+}
+
+case class Department(name:String)
+
+object EmployeeDesignWithApplyRunner extends App
+{
+    val e1 = Employee("Bruce", "Wayne", "BatMan")
+    println(e1.hireDate)
+    
+    val department = Department.apply("Sports")
+    val department2 = Department("Sports")
+    println(department)
+    println(department2)
+}
+
+/**
+    Sample Output
+    
+> scalac EmployeeDesignWithApply.scala
+
+> scala EmployeeDesignWithApplyRunner
+2017-05-02
+Department(Sports)
+Department(Sports)
+**/

Methods/InfixOperators.scala

@@ -0,0 +1,40 @@
+class Foo(x:Int)
+{
+    def bar(y:Int) = x + y
+    def baz(a:Int, b:Int) = x + a + b
+    def bab(y:Int) = new Foo(x + y)
+    def qux(y:Int) = new Foo(x + y)
+
+}
+
+object InfixOperatorRunner extends App
+{
+    val foo = new Foo(10)
+    println("foo.bar(5) = " + foo.bar(5))
+    println("foo bar 5 = " + (foo bar 5 ))
+    println("foo.baz(10, 14) = " + foo.baz(10, 14))
+    println("foo baz (10, 14) = " + (foo baz (10, 14)))
+    
+    //infix operators are similar to mathematical operators in scala 
+    //e.g.consider following examples
+    println("3.+(10) = " + (3.+(10)))
+    println("foo bar 4 + 19 = " + ((foo bar 4) + 19))
+    
+    //chaining of infix operators
+//    println(foo bab 4 bab 10 bab 19 bab (100 + 20) bar 40 + 300)
+    println(foo qux 4 qux 10 qux 19 qux (100 + 19) bar 40 + 300)
+}
+
+/**
+    Sample Output
+> scalac InfixOperators.scala
+
+> scala InfixOperatorRunner
+foo.bar(5) = 15
+foo bar 5 = 15
+foo.baz(10, 14) = 34
+foo baz (10, 14) = 34
+3.+(10) = 13
+foo bar 4 + 19 = 33
+502
+**/