move stream API to core-java-8 (#3403)

* make sure modules using java8 * move url matching code * upgrade boot parent * minor cleanup * fix blocking tests * add core-java-io module * move stream API to core-java-8
2018-01-13 15:58:51 +02:00
parent fc8e9ae24a
commit 6f3710b9ae
7 changed files with 23 additions and 3 deletions
@@ -0,0 +1,62 @@
+package com.baeldung.stream;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+import com.codepoetics.protonpack.Indexed;
+import com.codepoetics.protonpack.StreamUtils;
+
+import io.vavr.collection.Stream;
+import one.util.streamex.EntryStream;
+
+public class StreamIndices {
+
+    public static List<String> getEvenIndexedStrings(String[] names) {
+        List<String> evenIndexedNames = IntStream.range(0, names.length)
+            .filter(i -> i % 2 == 0)
+            .mapToObj(i -> names[i])
+            .collect(Collectors.toList());
+        return evenIndexedNames;
+    }
+
+    public List<String> getEvenIndexedStringsVersionTwo(List<String> names) {
+        List<String> evenIndexedNames = EntryStream.of(names)
+            .filterKeyValue((index, name) -> index % 2 == 0)
+            .values()
+            .toList();
+        return evenIndexedNames;
+    }
+
+    public static List<Indexed<String>> getEvenIndexedStrings(List<String> names) {
+        List<Indexed<String>> list = StreamUtils.zipWithIndex(names.stream())
+            .filter(i -> i.getIndex() % 2 == 0)
+            .collect(Collectors.toList());
+        return list;
+    }
+
+    public static List<Indexed<String>> getOddIndexedStrings(List<String> names) {
+        List<Indexed<String>> list = StreamUtils.zipWithIndex(names.stream())
+            .filter(i -> i.getIndex() % 2 == 1)
+            .collect(Collectors.toList());
+        return list;
+    }
+
+    public static List<String> getOddIndexedStrings(String[] names) {
+        List<String> oddIndexedNames = IntStream.range(0, names.length)
+            .filter(i -> i % 2 == 1)
+            .mapToObj(i -> names[i])
+            .collect(Collectors.toList());
+        return oddIndexedNames;
+    }
+
+    public static List<String> getOddIndexedStringsVersionTwo(String[] names) {
+        List<String> oddIndexedNames = Stream.of(names)
+            .zipWithIndex()
+            .filter(tuple -> tuple._2 % 2 == 1)
+            .map(tuple -> tuple._1)
+            .toJavaList();
+        return oddIndexedNames;
+    }
+
+}