Add more stream examples

winterbe · winterbe · commit c89625c1d45a · 2014-07-16T08:18:20.000+02:00
diff --git a/src/com/winterbe/java8/Streams5.java b/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));
+    }
+
+}
