Use local variable type inference (#995)

* "visitor" pattern: Use local variable type inference

Update "visitor" pattern with local variable type inference.

* "value-object" pattern: Use local variable type inference

Update "value-object" pattern with local variable type inference.

* "unit-of-work" pattern: Use local variable type inference

Update "value-object" pattern with local variable type inference.

* "typeobjectpattern" pattern: Use local variable type inference

Update "value-object" pattern with local variable type inference.

typeobjectpattern/src/main/java/com/iluwatar/typeobject/App.java

@@ -53,17 +53,17 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) throws FileNotFoundException, IOException, ParseException {
-    int givenTime = 50; //50ms
+    var givenTime = 50; //50ms
-    int toWin = 500; //points
+    var toWin = 500; //points
-    int pointsWon = 0;
+    var pointsWon = 0;
-    int numOfRows = 3;
+    var numOfRows = 3;
-    long start = System.currentTimeMillis();
+    var start = System.currentTimeMillis();
-    long end = System.currentTimeMillis();
+    var end = System.currentTimeMillis();
-    int round = 0;
+    var round = 0;
     while (pointsWon < toWin && end - start < givenTime) {      
       round++;
-      CellPool pool = new CellPool(numOfRows * numOfRows + 5);
+      var pool = new CellPool(numOfRows * numOfRows + 5);
-      CandyGame cg = new CandyGame(numOfRows, pool);
+      var cg = new CandyGame(numOfRows, pool);
       if (round > 1) {
         LOGGER.info("Refreshing..");
       } else {

typeobjectpattern/src/main/java/com/iluwatar/typeobject/CandyGame.java

@@ -44,8 +44,8 @@ public class CandyGame {
     this.cells = new Cell[num][num];
     this.pool = pool;
     this.totalPoints = 0;
-    for (int i = 0; i < num; i++) {
+    for (var i = 0; i < num; i++) {
-      for (int j = 0; j < num; j++) {
+      for (var j = 0; j < num; j++) {
         this.cells[i][j] = this.pool.getNewCell();
         this.cells[i][j].xIndex = j;
         this.cells[i][j].yIndex = i;
@@ -55,7 +55,7 @@ public class CandyGame {
   
   static String numOfSpaces(int num) {
     String result = "";
-    for (int i = 0; i < num; i++) {
+    for (var i = 0; i < num; i++) {
       result += " ";
     }
     return result;
@@ -63,11 +63,11 @@ public class CandyGame {
   
   void printGameStatus() {
     LOGGER.info("");
-    for (int i = 0; i < cells.length; i++) {
+    for (var i = 0; i < cells.length; i++) {
-      for (int j = 0; j < cells.length; j++) {
+      for (var j = 0; j < cells.length; j++) {
-        String candyName = cells[i][j].candy.name;
+        var candyName = cells[i][j].candy.name;
         if (candyName.length() < 20) {
-          int totalSpaces = 20 - candyName.length();
+          var totalSpaces = 20 - candyName.length();
           LOGGER.info(numOfSpaces(totalSpaces / 2) + cells[i][j].candy.name
               + numOfSpaces(totalSpaces - totalSpaces / 2) + "|");
         } else {
@@ -105,16 +105,16 @@ public class CandyGame {
   }
    
   boolean continueRound() {
-    for (int i = 0; i < this.cells.length; i++) {
+    for (var i = 0; i < this.cells.length; i++) {
       if (this.cells[cells.length - 1][i].candy.getType().equals(Type.rewardFruit)) {
         return true;
       }
     }
-    for (int i = 0; i < this.cells.length; i++) {
+    for (var i = 0; i < this.cells.length; i++) {
-      for (int j = 0; j < this.cells.length; j++) {
+      for (var j = 0; j < this.cells.length; j++) {
         if (!this.cells[i][j].candy.getType().equals(Type.rewardFruit)) {
-          ArrayList<Cell> adj = adjacentCells(i,j);
+          var adj = adjacentCells(i,j);
-          for (int a = 0; a < adj.size(); a++) {
+          for (var a = 0; a < adj.size(); a++) {
             if (this.cells[i][j].candy.name.equals(adj.get(a).candy.name)) {
               return true;
             }
@@ -132,21 +132,21 @@ public class CandyGame {
   }
   
   void round(int timeSoFar, int totalTime) {
-    long start = System.currentTimeMillis();
+    var start = System.currentTimeMillis();
-    long end = System.currentTimeMillis();
+    var end = System.currentTimeMillis();
     while (end - start + timeSoFar < totalTime && continueRound()) {
-      for (int i = 0; i < this.cells.length; i++) {
+      for (var i = 0; i < this.cells.length; i++) {
-        int points = 0;
+        var points = 0;
-        int j = this.cells.length - 1;
+        var j = this.cells.length - 1;
         while (this.cells[j][i].candy.getType().equals(Type.rewardFruit)) {
           points = this.cells[j][i].candy.getPoints();
           this.cells[j][i].crush(pool, this.cells);
           handleChange(points);
         }
       }
-      for (int i = 0; i < this.cells.length; i++) {
+      for (var i = 0; i < this.cells.length; i++) {
-        int j = cells.length - 1;
+        var j = cells.length - 1;
-        int points = 0;
+        var points = 0;
         while (j > 0) { 
           points = this.cells[j][i].interact(this.cells[j - 1][i], this.pool, this.cells);
           if (points != 0) {  
@@ -156,9 +156,9 @@ public class CandyGame {
           }
         }
       }
-      for (int i = 0; i < this.cells.length; i++) {
+      for (var i = 0; i < this.cells.length; i++) {
-        int j = 0;
+        var j = 0;
-        int points = 0;
+        var points = 0;
         while (j < cells.length - 1) {       
           points = this.cells[i][j].interact(this.cells[i][j + 1], this.pool, this.cells);
           if (points != 0) {

typeobjectpattern/src/main/java/com/iluwatar/typeobject/Cell.java

@@ -53,11 +53,11 @@ public class Cell {
   }
   
   void fillThisSpace(CellPool pool, Cell[][] cellMatrix) {
-    for (int y = this.yIndex; y > 0; y--) {
+    for (var y = this.yIndex; y > 0; y--) {
       cellMatrix[y][this.xIndex] = cellMatrix[y - 1][this.xIndex];
       cellMatrix[y][this.xIndex].yIndex = y;
     }
-    Cell newC = pool.getNewCell();
+    var newC = pool.getNewCell();
     cellMatrix[0][this.xIndex] = newC;
     cellMatrix[0][this.xIndex].xIndex = this.xIndex;
     cellMatrix[0][this.xIndex].yIndex = 0;
@@ -78,7 +78,7 @@ public class Cell {
       return 0;
     } else {
       if (this.candy.name.equals(c.candy.name)) {
-        int pointsWon = this.candy.getPoints() + c.candy.getPoints();
+        var pointsWon = this.candy.getPoints() + c.candy.getPoints();
         handleCrush(c,pool,cellMatrix);
         return pointsWon;
       } else {

typeobjectpattern/src/main/java/com/iluwatar/typeobject/CellPool.java

@@ -57,7 +57,7 @@ public class CellPool {
       randomCode[4] = new Candy("orange gum", "candy", Type.crushableCandy, 10);
     }
     for (int i = 0; i < num; i++) {
-      Cell c = new Cell();
+      var c = new Cell();
       c.candy = randomCode[RANDOM.nextInt(randomCode.length)];
       this.pool.add(c);
     }
@@ -65,7 +65,7 @@ public class CellPool {
   }
   
   Cell getNewCell() {
-    Cell newCell = this.pool.remove(pointer);
+    var newCell = this.pool.remove(pointer);
     pointer--;
     return newCell;
   }
@@ -77,12 +77,12 @@ public class CellPool {
   }
   
   Candy[] assignRandomCandytypes() throws FileNotFoundException, IOException, ParseException {
-    JsonParser jp = new JsonParser();
+    var jp = new JsonParser();
     jp.parse();
-    Candy[] randomCode = new Candy[jp.candies.size() - 2]; //exclude generic types 'fruit' and 'candy'
+    var randomCode = new Candy[jp.candies.size() - 2]; //exclude generic types 'fruit' and 'candy'
-    int i = 0;
+    var i = 0;
-    for (Enumeration<String> e = jp.candies.keys(); e.hasMoreElements();) {
+    for (var e = jp.candies.keys(); e.hasMoreElements();) {
-      String s = e.nextElement();
+      var s = e.nextElement();
       if (!s.equals("fruit") && !s.equals("candy")) {
         //not generic
         randomCode[i] = jp.candies.get(s);

typeobjectpattern/src/main/java/com/iluwatar/typeobject/JsonParser.java

@@ -47,23 +47,23 @@ public class JsonParser {
   }
 
   void parse() throws FileNotFoundException, IOException, ParseException {
-    JSONParser parser = new JSONParser();
+    var parser = new JSONParser();
-    JSONObject jo = (JSONObject) parser.parse(new FileReader(new File("").getAbsolutePath()
+    var jo = (JSONObject) parser.parse(new FileReader(new File("").getAbsolutePath()
         + "\\src\\main\\java\\com\\iluwatar\\typeobject\\candy.json"));
-    JSONArray a = (JSONArray) jo.get("candies");
+    var a = (JSONArray) jo.get("candies");
-    for (Object o : a) {
+    for (var o : a) {
-      JSONObject candy = (JSONObject) o;
+      var candy = (JSONObject) o;
-      String name = (String) candy.get("name");
+      var name = (String) candy.get("name");
-      String parentName = (String) candy.get("parent");
+      var parentName = (String) candy.get("parent");
-      String t = (String) candy.get("type");
+      var t = (String) candy.get("type");
       Type type = null;
       if (t.equals("rewardFruit")) {
         type = Type.rewardFruit;
       } else {
         type = Type.crushableCandy;
       }
-      int points = Integer.parseInt((String) candy.get("points"));
+      var points = Integer.parseInt((String) candy.get("points"));
-      Candy c = new Candy(name, parentName, type, points);
+      var c = new Candy(name, parentName, type, points);
       this.candies.put(name, c);
     }
     setParentAndPoints();
@@ -71,7 +71,7 @@ public class JsonParser {
   
   void setParentAndPoints() {
     for (Enumeration<String> e = this.candies.keys(); e.hasMoreElements();) {
-      Candy c = this.candies.get(e.nextElement());
+      var c = this.candies.get(e.nextElement());
       if (c.parentName == null) {
         c.parent = null;
       } else {

typeobjectpattern/src/test/java/com/iluwatar/typeobject/CandyGameTest.java

@@ -35,33 +35,33 @@ class CandyGameTest {
 
   @Test
   void adjacentCellsTest() {
-    CandyGame cg = new CandyGame(3,new CellPool(9));
+    var cg = new CandyGame(3,new CellPool(9));
-    ArrayList<Cell> arr1 = cg.adjacentCells(0, 0);
+    var arr1 = cg.adjacentCells(0, 0);
-    ArrayList<Cell> arr2 = cg.adjacentCells(1, 2);
+    var arr2 = cg.adjacentCells(1, 2);
-    ArrayList<Cell> arr3 = cg.adjacentCells(1, 1);
+    var arr3 = cg.adjacentCells(1, 1);
     assertTrue(arr1.size() == 2 && arr2.size() == 3 && arr3.size() == 4);
   }
 
   @Test
   void continueRoundTest() {
-    Cell[][] matrix = new Cell[2][2];
+    var matrix = new Cell[2][2];
-    Candy c1 = new Candy("green jelly", "jelly", Type.crushableCandy, 5);
+    var c1 = new Candy("green jelly", "jelly", Type.crushableCandy, 5);
-    Candy c2 = new Candy("purple jelly", "jelly", Type.crushableCandy, 5);
+    var c2 = new Candy("purple jelly", "jelly", Type.crushableCandy, 5);
-    Candy c3 = new Candy("green apple", "apple", Type.rewardFruit, 10);
+    var c3 = new Candy("green apple", "apple", Type.rewardFruit, 10);
     matrix[0][0] = new Cell(c1,0,0);;
     matrix[0][1] = new Cell(c2,1,0);
     matrix[1][0] = new Cell(c3,0,1);
     matrix[1][1] = new Cell(c2,1,1);
-    CellPool p = new CellPool(4);
+    var p = new CellPool(4);
-    CandyGame cg = new CandyGame(2,p);
+    var cg = new CandyGame(2,p);
     cg.cells = matrix;
-    boolean fruitInLastRow = cg.continueRound();
+    var fruitInLastRow = cg.continueRound();
     matrix[1][0].crush(p, matrix);
     matrix[0][0] = new Cell(c3,0,0);
-    boolean matchingCandy = cg.continueRound(); 
+    var matchingCandy = cg.continueRound(); 
     matrix[0][1].crush(p,matrix);
     matrix[0][1] = new Cell(c3,1,0);
-    boolean noneLeft = cg.continueRound();
+    var noneLeft = cg.continueRound();
     assertTrue(fruitInLastRow && matchingCandy && !noneLeft);
   }
 

typeobjectpattern/src/test/java/com/iluwatar/typeobject/CellPoolTest.java

@@ -34,10 +34,10 @@ class CellPoolTest {
 
   @Test
   void assignRandomCandyTypesTest() {
-    CellPool cp = new CellPool(10);
+    var cp = new CellPool(10);
-    Hashtable<String, Boolean> ht = new Hashtable<String, Boolean>();
+    var ht = new Hashtable<String, Boolean>();
-    int parentTypes = 0;
+    var parentTypes = 0;
-    for (int i = 0; i < cp.randomCode.length; i++) {
+    for (var i = 0; i < cp.randomCode.length; i++) {
       if (ht.get(cp.randomCode[i].name) == null) {
         ht.put(cp.randomCode[i].name, true);
       }

typeobjectpattern/src/test/java/com/iluwatar/typeobject/CellTest.java

@@ -34,24 +34,24 @@ class CellTest {
 
   @Test
   void interactTest() {
-    Candy c1 = new Candy("green jelly", "jelly", Type.crushableCandy, 5);
+    var c1 = new Candy("green jelly", "jelly", Type.crushableCandy, 5);
-    Candy c2 = new Candy("green apple", "apple", Type.rewardFruit, 10);
+    var c2 = new Candy("green apple", "apple", Type.rewardFruit, 10);
-    Cell[][] matrix = new Cell[4][4];
+    var matrix = new Cell[4][4];
     matrix[0][0] = new Cell(c1,0,0);
     matrix[0][1] = new Cell(c1,1,0);
     matrix[0][2] = new Cell(c2,2,0);
     matrix[0][3] = new Cell(c1,3,0);
-    CellPool cp = new CellPool(5);
+    var cp = new CellPool(5);
-    int points1 = matrix[0][0].interact(matrix[0][1], cp, matrix);
+    var points1 = matrix[0][0].interact(matrix[0][1], cp, matrix);
-    int points2 = matrix[0][2].interact(matrix[0][3], cp, matrix);
+    var points2 = matrix[0][2].interact(matrix[0][3], cp, matrix);
     assertTrue(points1 > 0 && points2 == 0);
   }
 
   @Test
   void crushTest() {
-    Candy c1 = new Candy("green jelly", "jelly", Type.crushableCandy, 5);
+    var c1 = new Candy("green jelly", "jelly", Type.crushableCandy, 5);
-    Candy c2 = new Candy("purple candy", "candy", Type.crushableCandy, 5);
+    var c2 = new Candy("purple candy", "candy", Type.crushableCandy, 5);
-    Cell[][] matrix = new Cell[4][4];
+    var matrix = new Cell[4][4];
     matrix[0][0] = new Cell(c1,0,0);
     matrix[1][0] = new Cell(c2,0,1);
     matrix[1][0].crush(new CellPool(5), matrix);

unit-of-work/src/main/java/com/iluwatar/unitofwork/App.java

@@ -34,13 +34,13 @@ public class App {
    * @param args no argument sent
    */
   public static void main(String[] args) {
-    Student ram = new Student(1, "Ram", "Street 9, Cupertino");
+    var ram = new Student(1, "Ram", "Street 9, Cupertino");
-    Student shyam = new Student(2, "Shyam", "Z bridge, Pune");
+    var shyam = new Student(2, "Shyam", "Z bridge, Pune");
-    Student gopi = new Student(3, "Gopi", "Street 10, Mumbai");
+    var gopi = new Student(3, "Gopi", "Street 10, Mumbai");
 
     HashMap<String, List<Student>> context = new HashMap<>();
-    StudentDatabase studentDatabase = new StudentDatabase();
+    var studentDatabase = new StudentDatabase();
-    StudentRepository studentRepository = new StudentRepository(context, studentDatabase);
+    var studentRepository = new StudentRepository(context, studentDatabase);
 
     studentRepository.registerNew(ram);
     studentRepository.registerModified(shyam);

unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentRepository.java

@@ -68,7 +68,7 @@ public class StudentRepository implements IUnitOfWork<Student> {
   }
 
   private void register(Student student, String operation) {
-    List<Student> studentsToOperate = context.get(operation);
+    var studentsToOperate = context.get(operation);
     if (studentsToOperate == null) {
       studentsToOperate = new ArrayList<>();
     }
@@ -99,24 +99,24 @@ public class StudentRepository implements IUnitOfWork<Student> {
   }
 
   private void commitInsert() {
-    List<Student> studentsToBeInserted = context.get(IUnitOfWork.INSERT);
+    var studentsToBeInserted = context.get(IUnitOfWork.INSERT);
-    for (Student student : studentsToBeInserted) {
+    for (var student : studentsToBeInserted) {
       LOGGER.info("Saving {} to database.", student.getName());
       studentDatabase.insert(student);
     }
   }
 
   private void commitModify() {
-    List<Student> modifiedStudents = context.get(IUnitOfWork.MODIFY);
+    var modifiedStudents = context.get(IUnitOfWork.MODIFY);
-    for (Student student : modifiedStudents) {
+    for (var student : modifiedStudents) {
       LOGGER.info("Modifying {} to database.", student.getName());
       studentDatabase.modify(student);
     }
   }
 
   private void commitDelete() {
-    List<Student> deletedStudents = context.get(IUnitOfWork.DELETE);
+    var deletedStudents = context.get(IUnitOfWork.DELETE);
-    for (Student student : deletedStudents) {
+    for (var student : deletedStudents) {
       LOGGER.info("Deleting {} to database.", student.getName());
       studentDatabase.delete(student);
     }

unit-of-work/src/test/java/com/iluwatar/unitofwork/StudentRepositoryTest.java

@@ -97,7 +97,7 @@ public class StudentRepositoryTest {
 
   @Test
   public void shouldNotWriteToDbIfContextIsNull() {
-    StudentRepository studentRepository = new StudentRepository(null, studentDatabase);
+    var studentRepository = new StudentRepository(null, studentDatabase);
 
     studentRepository.commit();
 
@@ -106,7 +106,7 @@ public class StudentRepositoryTest {
 
   @Test
   public void shouldNotWriteToDbIfNothingToCommit() {
-    StudentRepository studentRepository = new StudentRepository(new HashMap<>(), studentDatabase);
+    var studentRepository = new StudentRepository(new HashMap<>(), studentDatabase);
 
     studentRepository.commit();
 

value-object/src/main/java/com/iluwatar/value/object/App.java

@@ -48,9 +48,9 @@ public class App {
    * This practice creates three HeroStats(Value object) and checks equality between those.
    */
   public static void main(String[] args) {
-    HeroStat statA = HeroStat.valueOf(10, 5, 0);
+    var statA = HeroStat.valueOf(10, 5, 0);
-    HeroStat statB = HeroStat.valueOf(10, 5, 0);
+    var statB = HeroStat.valueOf(10, 5, 0);
-    HeroStat statC = HeroStat.valueOf(5, 1, 8);
+    var statC = HeroStat.valueOf(5, 1, 8);
 
     LOGGER.info(statA.toString());
 

value-object/src/main/java/com/iluwatar/value/object/HeroStat.java

@@ -76,8 +76,8 @@ public class HeroStat {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
+    final var prime = 31;
-    int result = 1;
+    var result = 1;
     result = prime * result + intelligence;
     result = prime * result + luck;
     result = prime * result + strength;
@@ -95,7 +95,7 @@ public class HeroStat {
     if (getClass() != obj.getClass()) {
       return false;
     }
-    HeroStat other = (HeroStat) obj;
+    var other = (HeroStat) obj;
     if (intelligence != other.intelligence) {
       return false;
     }

value-object/src/test/java/com/iluwatar/value/object/HeroStatTest.java

@@ -45,8 +45,8 @@ public class HeroStatTest {
    */
   @Test
   public void testEquals() {
-    HeroStat heroStatA = HeroStat.valueOf(3, 9, 2);
+    var heroStatA = HeroStat.valueOf(3, 9, 2);
-    HeroStat heroStatB = HeroStat.valueOf(3, 9, 2);
+    var heroStatB = HeroStat.valueOf(3, 9, 2);
     new EqualsTester().addEqualityGroup(heroStatA, heroStatB).testEquals();
   }
 
@@ -56,9 +56,9 @@ public class HeroStatTest {
    */
   @Test
   public void testToString() {
-    HeroStat heroStatA = HeroStat.valueOf(3, 9, 2);
+    var heroStatA = HeroStat.valueOf(3, 9, 2);
-    HeroStat heroStatB = HeroStat.valueOf(3, 9, 2);
+    var heroStatB = HeroStat.valueOf(3, 9, 2);
-    HeroStat heroStatC = HeroStat.valueOf(3, 9, 8);
+    var heroStatC = HeroStat.valueOf(3, 9, 8);
 
     assertThat(heroStatA.toString(), is(heroStatB.toString()));
     assertThat(heroStatA.toString(), is(not(heroStatC.toString())));

visitor/src/main/java/com/iluwatar/visitor/App.java

@@ -41,7 +41,7 @@ public class App {
    */
   public static void main(String[] args) {
 
-    Commander commander =
+    var commander =
         new Commander(new Sergeant(new Soldier(), new Soldier(), new Soldier()), new Sergeant(
             new Soldier(), new Soldier(), new Soldier()));
     commander.accept(new SoldierVisitor());

visitor/src/main/java/com/iluwatar/visitor/Unit.java

@@ -39,7 +39,7 @@ public abstract class Unit {
    * Accept visitor
    */
   public void accept(UnitVisitor visitor) {
-    for (Unit child : children) {
+    for (var child : children) {
       child.accept(visitor);
     }
   }

visitor/src/test/java/com/iluwatar/visitor/UnitTest.java

@@ -56,15 +56,15 @@ public abstract class UnitTest<U extends Unit> {
 
   @Test
   public void testAccept() {
-    final Unit[] children = new Unit[5];
+    final var children = new Unit[5];
     Arrays.setAll(children, (i) -> mock(Unit.class));
 
-    final U unit = this.factory.apply(children);
+    final var unit = this.factory.apply(children);
-    final UnitVisitor visitor = mock(UnitVisitor.class);
+    final var visitor = mock(UnitVisitor.class);
     unit.accept(visitor);
     verifyVisit(unit, visitor);
 
-    for (final Unit child : children) {
+    for (final var child : children) {
       verify(child).accept(eq(visitor));
     }