Rewrites

collectiontopics/QueueBehavior.java

@@ -2,36 +2,49 @@
 // (c)2017 MindView LLC: see Copyright.txt
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
-// Compares the behavior of some of the queues
-import java.util.concurrent.*;
+// Compares basic behavior
 import java.util.*;
+import java.util.stream.*;
+import java.util.concurrent.*;
 
 public class QueueBehavior {
-  private static String[] s =
-    ("one two three four five six seven " +
-    "eight nine ten").split(" ");
-  static void test(Queue<String> queue) {
-    for(String ss : s)
-      queue.offer(ss);
+  static Stream<String> strings() {
+    return Arrays.stream(
+      ("one two three four five six seven " +
+       "eight nine ten").split(" "));
+  }
+  static void test(int id, Queue<String> queue) {
+    System.out.print(id + ": ");
+    strings().map(queue::offer).count();
     while(queue.peek() != null)
       System.out.print(queue.remove() + " ");
     System.out.println();
   }
   public static void main(String[] args) {
-   int count = 10;
-   test(new LinkedList<>());
-    test(new PriorityQueue<>());
-    test(new ArrayBlockingQueue<>(count));
-    test(new ConcurrentLinkedQueue<>());
-    test(new LinkedBlockingQueue<>());
-    test(new PriorityBlockingQueue<>());
+    int count = 10;
+    test(1, new LinkedList<>());
+    test(2, new PriorityQueue<>());
+    test(3, new ArrayBlockingQueue<>(count));
+    test(4, new ConcurrentLinkedQueue<>());
+    test(5, new LinkedBlockingQueue<>());
+    test(6, new PriorityBlockingQueue<>());
+    test(7, new ArrayDeque<>());
+    test(8, new ConcurrentLinkedDeque<>());
+    test(9, new LinkedBlockingDeque<>());
+    test(10, new LinkedTransferQueue<>());
+    test(11, new SynchronousQueue<>());
   }
 }
 /* Output:
-one two three four five six seven eight nine ten
-eight five four nine one seven six ten three two
-one two three four five six seven eight nine ten
-one two three four five six seven eight nine ten
-one two three four five six seven eight nine ten
-eight five four nine one seven six ten three two
+1: one two three four five six seven eight nine ten
+2: eight five four nine one seven six ten three two
+3: one two three four five six seven eight nine ten
+4: one two three four five six seven eight nine ten
+5: one two three four five six seven eight nine ten
+6: eight five four nine one seven six ten three two
+7: one two three four five six seven eight nine ten
+8: one two three four five six seven eight nine ten
+9: one two three four five six seven eight nine ten
+10: one two three four five six seven eight nine ten
+11:
 */

collectiontopics/SimpleDeques.java

@@ -3,8 +3,8 @@
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
 // Very basic test of Deques
-import java.util.concurrent.*;
 import java.util.*;
+import java.util.concurrent.*;
 import java.util.function.*;
 
 class CountString implements Supplier<String> {
@@ -12,7 +12,9 @@ class CountString implements Supplier<String> {
   public CountString() {}
   public CountString(int start) { n = start; }
   @Override
-  public String get() { return Integer.toString(n++); }
+  public String get() {
+    return Integer.toString(n++);
+  }
 }
 
 public class SimpleDeques {

collectiontopics/SortedSetDemo.java

@@ -2,15 +2,16 @@
 // (c)2017 MindView LLC: see Copyright.txt
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
-// What you can do with a TreeSet
 import java.util.*;
+import static java.util.stream.Collectors.*;
 
 public class SortedSetDemo {
   public static void main(String[] args) {
-    SortedSet<String> sortedSet = new TreeSet<>();
-    Collections.addAll(sortedSet,
-      "one two three four five six seven eight"
-        .split(" "));
+    SortedSet<String> sortedSet =
+      Arrays.stream(
+        "one two three four five six seven eight"
+        .split(" "))
+        .collect(toCollection(TreeSet::new));
     System.out.println(sortedSet);
     String low = sortedSet.first();
     String high = sortedSet.last();

collectiontopics/ToDoList.java

@@ -5,44 +5,42 @@
 // A more complex use of PriorityQueue
 import java.util.*;
 
-class ToDoList extends PriorityQueue<ToDoList.ToDoItem> {
-  static class ToDoItem implements Comparable<ToDoItem> {
-    private char primary;
-    private int secondary;
-    private String item;
-    public ToDoItem(String td, char pri, int sec) {
-      primary = pri;
-      secondary = sec;
-      item = td;
-    }
-    @Override
-    public int compareTo(ToDoItem arg) {
-      if(primary > arg.primary)
+class ToDoItem implements Comparable<ToDoItem> {
+  private char primary;
+  private int secondary;
+  private String item;
+  public ToDoItem(String td, char pri, int sec) {
+    primary = pri;
+    secondary = sec;
+    item = td;
+  }
+  @Override
+  public int compareTo(ToDoItem arg) {
+    if(primary > arg.primary)
+      return +1;
+    if(primary == arg.primary)
+      if(secondary > arg.secondary)
         return +1;
-      if(primary == arg.primary)
-        if(secondary > arg.secondary)
-          return +1;
-        else if(secondary == arg.secondary)
-          return 0;
-      return -1;
-    }
-    @Override
-    public String toString() {
-      return Character.toString(primary) +
-        secondary + ": " + item;
-    }
+      else if(secondary == arg.secondary)
+        return 0;
+    return -1;
   }
-  public void add(String td, char pri, int sec) {
-    super.add(new ToDoItem(td, pri, sec));
+  @Override
+  public String toString() {
+    return Character.toString(primary) +
+      secondary + ": " + item;
   }
+}
+
+class ToDoList {
   public static void main(String[] args) {
-    ToDoList toDo = new ToDoList();
-    toDo.add("Empty trash", 'C', 4);
-    toDo.add("Feed dog", 'A', 2);
-    toDo.add("Feed bird", 'B', 7);
-    toDo.add("Mow lawn", 'C', 3);
-    toDo.add("Water lawn", 'A', 1);
-    toDo.add("Feed cat", 'B', 1);
+    PriorityQueue<ToDoItem> toDo = new PriorityQueue<>();
+    toDo.add(new ToDoItem("Empty trash", 'C', 4));
+    toDo.add(new ToDoItem("Feed dog", 'A', 2));
+    toDo.add(new ToDoItem("Feed bird", 'B', 7));
+    toDo.add(new ToDoItem("Mow lawn", 'C', 3));
+    toDo.add(new ToDoItem("Water lawn", 'A', 1));
+    toDo.add(new ToDoItem("Feed cat", 'B', 1));
     while(!toDo.isEmpty())
       System.out.println(toDo.remove());
   }

collectiontopics/TypesForSets.java

@@ -6,9 +6,10 @@
 import java.util.*;
 import java.util.function.*;
 import java.util.Objects;
+import onjava.CountMap;
 
 class SetType {
-  int i;
+  protected int i;
   public SetType(int n) { i = n; }
   @Override
   public boolean equals(Object o) {
@@ -16,13 +17,17 @@ class SetType {
       Objects.equals(i, ((SetType)o).i);
   }
   @Override
-  public int hashCode() { return Objects.hash(i); }
-  @Override
-  public String toString() { return Integer.toString(i); }
+  public String toString() {
+    return Integer.toString(i);
+  }
 }
 
 class HashType extends SetType {
   public HashType(int n) { super(n); }
+  @Override
+  public int hashCode() {
+    return Objects.hashCode(i);
+  }
 }
 
 class TreeType extends SetType
@@ -30,16 +35,19 @@ implements Comparable<TreeType> {
   public TreeType(int n) { super(n); }
   @Override
   public int compareTo(TreeType arg) {
-    return (arg.i < i ? -1 : (arg.i == i ? 0 : 1));
+    return Integer.compare(arg.i, i);
+    // Equivalent to:
+    // return arg.i < i ? -1 : (arg.i == i ? 0 : 1);
   }
 }
 
 public class TypesForSets {
-  static <T> Set<T>
+  static <T> void
   fill(Set<T> set, Function<Integer, T> type) {
-    for(int i = 0; i < 10; i++)
-        set.add(type.apply(i));
-    return set;
+    for(int i = 10; i >= 5; i--) // Descending
+      set.add(type.apply(i));
+    for(int i = 0; i < 5; i++) // Ascending
+      set.add(type.apply(i));
   }
   static <T> void
   test(Set<T> set, Function<Integer, T> type) {
@@ -60,23 +68,27 @@ public class TypesForSets {
     try {
       test(new TreeSet<>(), SetType::new);
     } catch(Exception e) {
-      System.out.println("Expected: " + e.getMessage());
+      System.out.println(e.getMessage());
     }
     try {
       test(new TreeSet<>(), HashType::new);
     } catch(Exception e) {
-      System.out.println("Expected: " + e.getMessage());
+      System.out.println(e.getMessage());
     }
   }
 }
 /* Output:
-[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
-[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
-[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
-[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
-[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
-[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
-[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
-Expected: SetType cannot be cast to java.lang.Comparable
-Expected: HashType cannot be cast to java.lang.Comparable
+[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+[10, 9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
+[10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
+[1, 6, 8, 6, 2, 7, 8, 9, 4, 10, 7, 5, 1, 3, 4, 9, 9,
+10, 5, 3, 2, 0, 4, 1, 2, 0, 8, 3, 0, 10, 6, 5, 7]
+[3, 1, 4, 8, 7, 6, 9, 5, 3, 0, 10, 5, 5, 10, 7, 8, 8,
+9, 1, 4, 10, 2, 6, 9, 1, 6, 0, 3, 2, 0, 7, 2, 4]
+[10, 9, 8, 7, 6, 5, 0, 1, 2, 3, 4, 10, 9, 8, 7, 6, 5,
+0, 1, 2, 3, 4, 10, 9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
+[10, 9, 8, 7, 6, 5, 0, 1, 2, 3, 4, 10, 9, 8, 7, 6, 5,
+0, 1, 2, 3, 4, 10, 9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
+SetType cannot be cast to java.lang.Comparable
+HashType cannot be cast to java.lang.Comparable
 */

onjava/CountMap.java

@@ -19,8 +19,7 @@ extends AbstractMap<Integer,String> {
       Integer.toString(key / chars.length);
   }
   public CountMap(int size) {
-    if(size < 0) this.size = 0;
-    else this.size = size;
+    this.size = size < 0 ? 0 : size;
   }
   @Override
   public String get(Object key) {
@@ -57,9 +56,17 @@ extends AbstractMap<Integer,String> {
         Collectors.toCollection(LinkedHashSet::new));
   }
   public static void main(String[] args) {
+    final int LIM = 6;
     CountMap cm = new CountMap(60);
     System.out.println(cm);
     System.out.println(cm.get(500));
+    cm.values().stream()
+      .limit(LIM)
+      .forEach(System.out::println);
+    System.out.println();
+    new Random().ints(LIM, 0, 1000)
+      .mapToObj(cm::get)
+      .forEach(System.out::println);
   }
 }
 /* Output:
@@ -72,4 +79,17 @@ extends AbstractMap<Integer,String> {
 49=X1, 50=Y1, 51=Z1, 52=A2, 53=B2, 54=C2, 55=D2, 56=E2,
 57=F2, 58=G2, 59=H2}
 G19
+A0
+B0
+C0
+D0
+E0
+F0
+
+E4
+X33
+P15
+L28
+M24
+Y36
 */

patterns/PaperScissorsRock.java

@@ -86,7 +86,8 @@ class ItemFactory {
     Arrays.asList(
       Scissors::new, Paper::new, Rock::new);
   static final int SZ = items.size();
-  private static SplittableRandom rand = new SplittableRandom(47);
+  private static SplittableRandom rand =
+    new SplittableRandom(47);
   public static Item newItem() {
     return items.get(rand.nextInt(SZ)).get();
   }

patterns/ShapeFactory1.java

@@ -7,8 +7,8 @@ import java.util.*;
 import java.util.stream.*;
 import patterns.shapes.*;
 
-class StaticFactory {
-  static Shape create(String type) {
+public class ShapeFactory1 implements FactoryMethod {
+  public Shape create(String type) {
     switch(type) {
       case "Circle": return new Circle();
       case "Square": return new Square();
@@ -17,16 +17,8 @@ class StaticFactory {
         throw new BadShapeCreation(type);
     }
   }
-}
-
-public class ShapeFactory1 {
   public static void main(String[] args) {
-    Stream.of("Circle", "Square", "Triangle",
-      "Square", "Circle", "Circle", "Triangle")
-      .map(StaticFactory::create)
-      .peek(Shape::draw)
-      .peek(Shape::erase)
-      .count(); // Terminal operation
+    FactoryTest.test(new ShapeFactory1());
   }
 }
 /* Output:

patterns/ShapeFactory2.java

@@ -7,37 +7,32 @@ import java.lang.reflect.*;
 import java.util.stream.*;
 import patterns.shapes.*;
 
-class DynamicFactory {
-  static Map<String, Constructor> factories =
+public class ShapeFactory2 implements FactoryMethod {
+  Map<String, Constructor> factories =
     new HashMap<>();
   static Constructor load(String id) {
     System.out.println("loading " + id);
     try {
       return Class.forName("patterns.shapes." + id)
         .getConstructor();
-    } catch(Exception e) {
+    } catch(ClassNotFoundException |
+            NoSuchMethodException e) {
       throw new BadShapeCreation(id);
     }
   }
-  static Shape create(String id) {
+  public Shape create(String id) {
     try {
       return (Shape)factories
-        .computeIfAbsent(id, DynamicFactory::load)
+        .computeIfAbsent(id, ShapeFactory2::load)
         .newInstance();
-    } catch(Exception e) {
+    } catch(InstantiationException |
+            IllegalAccessException |
+            InvocationTargetException e) {
       throw new BadShapeCreation(id);
     }
   }
-}
-
-public class ShapeFactory2 {
   public static void main(String[] args) {
-    Stream.of("Circle", "Square", "Triangle",
-      "Square", "Circle", "Circle", "Triangle")
-      .map(DynamicFactory::create)
-      .peek(Shape::draw)
-      .peek(Shape::erase)
-      .count();
+    FactoryTest.test(new ShapeFactory2());
   }
 }
 /* Output:

patterns/doubledispatch/TypedBinMember.java

@@ -8,7 +8,7 @@
 package patterns.doubledispatch;
 import java.util.*;
 
-interface TypedBinMember {
+public interface TypedBinMember {
   // The new method:
   boolean addToBin(List<TypedBin> bins);
 }

patterns/shapes/FactoryMethod.java

@@ -0,0 +1,9 @@
+// patterns/shapes/FactoryMethod.java
+// (c)2017 MindView LLC: see Copyright.txt
+// We make no guarantees that this code is fit for any purpose.
+// Visit http://OnJava8.com for more book information.
+package patterns.shapes;
+
+public interface FactoryMethod {
+  Shape create(String type);
+}

patterns/shapes/FactoryTest.java

@@ -0,0 +1,17 @@
+// patterns/shapes/FactoryTest.java
+// (c)2017 MindView LLC: see Copyright.txt
+// We make no guarantees that this code is fit for any purpose.
+// Visit http://OnJava8.com for more book information.
+package patterns.shapes;
+import java.util.stream.*;
+
+public class FactoryTest {
+  public static void test(FactoryMethod factory) {
+    Stream.of("Circle", "Square", "Triangle",
+      "Square", "Circle", "Circle", "Triangle")
+      .map(factory::create)
+      .peek(Shape::draw)
+      .peek(Shape::erase)
+      .count(); // Terminal operation
+  }
+}

patterns/trash/Trash.java

@@ -66,8 +66,8 @@ public abstract class Trash {
         try {
           // Get the dynamic constructor method
           // that takes a double argument:
-          Constructor ctor = trashType.getConstructor(
-                  double.class);
+          Constructor ctor =
+            trashType.getConstructor(double.class);
           // Call the constructor to create a
           // new object:
           return (T)ctor.newInstance(info.data);

patterns/trashvisitor/Visitable.java

@@ -6,7 +6,7 @@
 // Trash hierarchy without modifying the base class
 package patterns.trashvisitor;
 
-interface Visitable {
+public interface Visitable {
   // The new method:
   void accept(Visitor v);
 }

patterns/trashvisitor/Visitor.java

@@ -5,7 +5,7 @@
 // The base interface for visitors
 package patterns.trashvisitor;
 
-interface Visitor {
+public interface Visitor {
   void visit(Aluminum a);
   void visit(Paper p);
   void visit(Glass g);

patterns/visitor/BeeAndFlowers.java

@@ -75,7 +75,8 @@ class FlowerFactory {
     Arrays.asList(Gladiolus::new,
       Renuculus::new, Chrysanthemum::new);
   static final int SZ = flowers.size();
-  private static SplittableRandom rand = new SplittableRandom(47);
+  private static SplittableRandom rand =
+    new SplittableRandom(47);
   public static Flower newFlower() {
     return flowers.get(rand.nextInt(SZ)).get();
   }