Add more stream examples

Author: winterbe

src/com/winterbe/java8/Streams6.java

@@ -0,0 +1,33 @@
+package com.winterbe.java8;
+
+import java.util.Optional;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Streams6 {
+
+ static class Outer {
+ Nested nested;
+ }
+
+ static class Nested {
+ Inner inner;
+ }
+
+ static class Inner {
+ String foo;
+ }
+
+ public static void main(String[] args) {
+ test1();
+ }
+
+ private static void test1() {
+ Optional.of(new Outer())
+ .flatMap(o -> Optional.ofNullable(o.nested))
+ .flatMap(n -> Optional.ofNullable(n.inner))
+ .flatMap(i -> Optional.ofNullable(i.foo))
+ .ifPresent(System.out::print);
+ }
+}

src/com/winterbe/java8/Streams7.java

@@ -0,0 +1,61 @@
+package com.winterbe.java8;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.IntStream;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Streams7 {
+
+ static class Foo {
+ String name;
+ List<Bar> bars = new ArrayList<>();
+
+ Foo(String name) {
+ this.name = name;
+ }
+ }
+
+ static class Bar {
+ String name;
+
+ Bar(String name) {
+ this.name = name;
+ }
+ }
+
+ public static void main(String[] args) {
+// test1();
+ test2();
+ }
+
+ static void test2() {
+ IntStream.range(1, 4)
+ .mapToObj(num -> new Foo("Foo" + num))
+ .peek(f -> IntStream.range(1, 4)
+ .mapToObj(num -> new Bar(f.name + " -> Bar" + num))
+ .forEach(f.bars::add))
+ .flatMap(f -> f.bars.stream())
+ .forEach(b -> System.out.println(b.name));
+ }
+
+ static void test1() {
+ List<Foo> foos = new ArrayList<>();
+
+ IntStream
+ .range(1, 4)
+ .forEach(num -> foos.add(new Foo("Foo" + num)));
+
+ foos.forEach(f ->
+ IntStream
+ .range(1, 4)
+ .forEach(num -> f.bars.add(new Bar(f.name + " -> Bar" + num))));
+
+ foos.stream()
+ .flatMap(f -> f.bars.stream())
+ .forEach(b -> System.out.println(b.name));
+ }
+
+}