Add more stream examples

Author: winterbe

src/com/winterbe/java8/Streams5.java

@@ -0,0 +1,134 @@
+package com.winterbe.java8;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Stream;
+
+/**
+ * Testing the order of execution.
+ *
+ * @author Benjamin Winterberg
+ */
+public class Streams5 {
+
+ public static void main(String[] args) {
+ List<String> stringCollection = new ArrayList<>();
+ stringCollection.add("ddd2");
+ stringCollection.add("aaa2");
+ stringCollection.add("bbb1");
+ stringCollection.add("aaa1");
+ stringCollection.add("bbb3");
+ stringCollection.add("ccc");
+ stringCollection.add("bbb2");
+ stringCollection.add("ddd1");
+
+// test1(stringCollection);
+// test2(stringCollection);
+// test3(stringCollection);
+// test4(stringCollection);
+// test5(stringCollection);
+// test6(stringCollection);
+ test7(stringCollection);
+ }
+
+ // stream has already been operated upon or closed
+ private static void test7(List<String> stringCollection) {
+ Stream<String> stream = stringCollection
+ .stream()
+ .filter(s -> s.toLowerCase().startsWith("a"));
+
+ stream.anyMatch(s -> true);
+ stream.noneMatch(s -> true);
+ }
+
+ // short-circuit
+ private static void test6(List<String> stringCollection) {
+ stringCollection
+ .stream()
+ .filter(s -> {
+ System.out.println("filter: " + s);
+ return s.toLowerCase().startsWith("a");
+ })
+ .map(s -> {
+ System.out.println("map: " + s);
+ return s.toUpperCase();
+ })
+ .anyMatch(s -> true);
+ }
+
+ private static void test5(List<String> stringCollection) {
+ stringCollection
+ .stream()
+ .filter(s -> {
+ System.out.println("filter: " + s);
+ return s.toLowerCase().startsWith("a");
+ })
+ .sorted((s1, s2) -> {
+ System.out.printf("sort: %s; %s\n", s1, s2);
+ return s1.compareTo(s2);
+ })
+ .map(s -> {
+ System.out.println("map: " + s);
+ return s.toUpperCase();
+ })
+ .forEach(s -> System.out.println("forEach: " + s));
+ }
+
+ // sorted = horizontal
+ private static void test4(List<String> stringCollection) {
+ stringCollection
+ .stream()
+ .sorted((s1, s2) -> {
+ System.out.printf("sort: %s; %s\n", s1, s2);
+ return s1.compareTo(s2);
+ })
+ .filter(s -> {
+ System.out.println("filter: " + s);
+ return s.toLowerCase().startsWith("a");
+ })
+ .map(s -> {
+ System.out.println("map: " + s);
+ return s.toUpperCase();
+ })
+ .forEach(s -> System.out.println("forEach: " + s));
+ }
+
+ private static void test3(List<String> stringCollection) {
+ stringCollection
+ .stream()
+ .filter(s -> {
+ System.out.println("filter: " + s);
+ return s.toLowerCase().startsWith("a");
+ })
+ .map(s -> {
+ System.out.println("map: " + s);
+ return s.toUpperCase();
+ })
+ .forEach(s -> System.out.println("forEach: " + s));
+ }
+
+ private static void test2(List<String> stringCollection) {
+ stringCollection
+ .stream()
+ .map(s -> {
+ System.out.println("map: " + s);
+ return s.toUpperCase();
+ })
+ .filter(s -> {
+ System.out.println("filter: " + s);
+ return s.toLowerCase().startsWith("a");
+ })
+ .forEach(s -> System.out.println("forEach: " + s));
+ }
+
+ private static void test1(List<String> stringCollection) {
+ stringCollection
+ .stream()
+ .filter(s -> {
+ System.out.println("filter: " + s);
+ return true;
+ })
+ .forEach(s -> System.out.println("forEach: " + s));
+ }
+
+}