[add] add example of ConstructorReference in module java 8

brianway · brianway · commit 0366f87accc5 · 2017-02-28T21:37:51.000+08:00
diff --git a/java8/src/main/java/com/brianway/learning/java8/lambda/ConstructorReference.java b/java8/src/main/java/com/brianway/learning/java8/lambda/ConstructorReference.java
@@ -0,0 +1,87 @@
+package com.brianway.learning.java8.lambda;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+/**
+ * Created by brian on 17/2/28.
+ * 构造函数引用
+ */
+public class ConstructorReference {
+
+    public static void main(String[] args) {
+        //Apple()的构造函数
+        Supplier<Apple> c1 = Apple::new;
+        Apple a1 = c1.get();
+        System.out.println(a1);
+
+        //Apple(int weight)的构造函数
+        Function<Integer, Apple> c2 = Apple::new;
+        Apple a2 = c2.apply(110);
+        System.out.println(a2);
+
+        List<Integer> weights = Arrays.asList(7, 3, 4, 10);
+        List<Apple> apples = map(weights, Apple::new);
+        System.out.println("list of weights:");
+        apples.stream().forEach(System.out::println);
+
+        //Apple(int weight, String color)的构造函数
+        BiFunction<String, Integer, Apple> c3 = Apple::new;
+        Apple a3 = c3.apply("green", 110);
+        System.out.println(a3);
+    }
+
+    public static List<Apple> map(List<Integer> list,
+                                  Function<Integer, Apple> f) {
+        List<Apple> result = new ArrayList<>();
+        //TODO
+        for (Integer e : list) {
+            result.add(f.apply(e));
+        }
+        return result;
+    }
+
+    public static class Apple {
+        private int weight = 0;
+        private String color = "";
+
+        public Apple() {
+        }
+
+        public Apple(int weight) {
+            this.weight = weight;
+        }
+
+        public Apple(String color, int weight) {
+            this.weight = weight;
+            this.color = color;
+        }
+
+        public Integer getWeight() {
+            return weight;
+        }
+
+        public void setWeight(Integer weight) {
+            this.weight = weight;
+        }
+
+        public String getColor() {
+            return color;
+        }
+
+        public void setColor(String color) {
+            this.color = color;
+        }
+
+        public String toString() {
+            return "Apple{" +
+                    "color='" + color + '\'' +
+                    ", weight=" + weight +
+                    '}';
+        }
+    }
+}
