new example for the Template Pattern

Author: codethought

source/behavioral/template.swift

@@ -0,0 +1,70 @@
+/*:
+🍪 Template
+-----------
+
+The Template Pattern is used when two or more implementations of an
+algorithm exist. The template is defined and then built upon with further
+variations. Use this method when most (or all) subclasses need to implement
+the same behavior. Traditionally, this would be accomplished with abstract
+classes (as in Java). However in Swift, because abstract classes don't yet
+exist,  we need to accomplish the behavior using interface delegation.
+
+
+### Example
+*/
+
+protocol ICodeGenerator {
+    func crossCompile()
+}
+
+protocol IGeneratorPhases {
+    func collectSource()
+    func crossCompile()
+}
+
+class CodeGenerator : ICodeGenerator{
+    var delegate: IGeneratorPhases
+
+    init(delegate: IGeneratorPhases) {
+        self.delegate = delegate
+    }
+
+
+    //Template method
+    final func crossCompile() {
+        delegate.collectSource()
+        delegate.crossCompile()
+    }
+}
+
+class HTMLGeneratorPhases : IGeneratorPhases {
+    func collectSource() {
+        print("HTMLGeneratorPhases collectSource() executed")
+    }
+
+    func crossCompile() {
+        print("HTMLGeneratorPhases crossCompile() executed")
+    }
+}
+
+class JSONGeneratorPhases : IGeneratorPhases {
+    func collectSource() {
+        print("JSONGeneratorPhases collectSource() executed")
+    }
+
+    func crossCompile() {
+        print("JSONGeneratorPhases crossCompile() executed")
+    }
+}
+
+
+
+/*:
+### Usage
+*/
+
+let htmlGen : ICodeGenerator = CodeGenerator(delegate: HTMLGeneratorPhases())
+let jsonGen: ICodeGenerator = CodeGenerator(delegate: JSONGeneratorPhases())
+
+htmlGen.crossCompile()
+jsonGen.crossCompile()