Merge pull request ochococo#42 from erykwarren/master

Suggestion for AbstractFactory using typealias to define factory type

Author: ochococo

source/creational/abstract_factory.swift

@@ -12,36 +12,32 @@ Protocols
 */
 protocol Decimal {
     func stringValue() -> String
+    // factory
+    static func make(string : String) -> Decimal
 }
 
-protocol NumberFactoryProtocol {
-    func numberFromString(string : String) -> Decimal
-}
+typealias NumberFactory = (String) -> Decimal
 
-// Number implementations
+// Number implementations with factory methods
 
 struct NextStepNumber : Decimal {
     private var nextStepNumber : NSNumber
 
     func stringValue() -> String { return nextStepNumber.stringValue }
+    
+    // factory
+    static func make(string : String) -> Decimal {
+        return NextStepNumber(nextStepNumber:NSNumber(longLong:(string as NSString).longLongValue))
+    }
 }
 
 struct SwiftNumber : Decimal {
     private var swiftInt : Int
 
     func stringValue() -> String { return "\(swiftInt)" }
-}
-/*:
-Factories
-*/
-class NextStepNumberFactory : NumberFactoryProtocol {
-    func numberFromString(string : String) -> Decimal {
-        return NextStepNumber(nextStepNumber:NSNumber(longLong:(string as NSString).longLongValue))
-    }
-}
-
-class SwiftNumberFactory : NumberFactoryProtocol {
-    func numberFromString(string : String) -> Decimal {
+    
+    // factory
+    static func make(string : String) -> Decimal {
         return SwiftNumber(swiftInt:(string as NSString).integerValue)
     }
 }
@@ -52,24 +48,23 @@ enum NumberType {
     case NextStep, Swift
 }
 
-class NumberAbstractFactory {
-    class func numberFactoryType(type : NumberType) -> NumberFactoryProtocol {
-        
+class NumberHelper {
+    class func factoryFor(type : NumberType) -> NumberFactory {
         switch type {
-            case .NextStep:
-                    return NextStepNumberFactory()
-            case .Swift:
-                    return SwiftNumberFactory()
+        case .NextStep:
+            return NextStepNumber.make
+        case .Swift:
+            return SwiftNumber.make
         }
     }
 }
 /*:
 ### Usage
 */
-let factoryOne = NumberAbstractFactory.numberFactoryType(.NextStep)
-let numberOne = factoryOne.numberFromString("1")
+let factoryOne = NumberHelper.factoryFor(.NextStep)
+let numberOne = factoryOne("1")
 numberOne.stringValue()
 
-let factoryTwo = NumberAbstractFactory.numberFactoryType(.Swift)
-let numberTwo = factoryTwo.numberFromString("2")
+let factoryTwo = NumberHelper.factoryFor(.Swift)
+let numberTwo = factoryTwo("2")
 numberTwo.stringValue()