Add more stream examples

winterbe · winterbe · commit 0e21011ec92d · 2014-07-17T17:47:05.000+02:00
diff --git a/src/com/winterbe/java8/Streams6.java b/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);
+    }
+}
diff --git a/src/com/winterbe/java8/Streams7.java b/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));
+    }
+
+}
