From d6407ef405e2a2568cb48beb56e998d3b37070d0 Mon Sep 17 00:00:00 2001
From: Harshil Sharma <harshilsharma63@gmail.com>
Date: Wed, 21 Feb 2018 16:16:15 +0530
Subject: [PATCH] BAEL-1539 shuffling collections (#3701)

* BAEL-1539 Added list, set and map shuffling code exaamples

* #BAEL-1539 fixed a typo

* #BAEL-1539 refactored sample code, added unit tests

* #BAEL-1539 Added unit tests and example for shuffling with custom randomness

* #BAEL-1539 removed source code and kept only tests as tests are sufficient code sample themselves

* #BAEL-1539 updated map shuffling example to use lambdas

* #BAEL-1539 lambda refactoring

* #BAEL-1539 updated map shuffling logic to shuffle entryset instead of keyset
---
 .../ShufflingCollectionsUnitTest.java                | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/core-java-8/src/test/java/com/baeldung/shufflingcollections/ShufflingCollectionsUnitTest.java b/core-java-8/src/test/java/com/baeldung/shufflingcollections/ShufflingCollectionsUnitTest.java
index 4823c7178a..d013907c9a 100644
--- a/core-java-8/src/test/java/com/baeldung/shufflingcollections/ShufflingCollectionsUnitTest.java
+++ b/core-java-8/src/test/java/com/baeldung/shufflingcollections/ShufflingCollectionsUnitTest.java
@@ -22,7 +22,7 @@ public class ShufflingCollectionsUnitTest {
     }
 
     @Test
-    public void whenShufflingMapKeys_thenValuesAreShuffled() {
+    public void whenShufflingMapEntries_thenValuesAreShuffled() {
         Map<Integer, String> studentsById = new HashMap<>();
         studentsById.put(1, "Foo");
         studentsById.put(2, "Bar");
@@ -32,12 +32,12 @@ public class ShufflingCollectionsUnitTest {
         System.out.println("Students before shuffling:");
         System.out.println(studentsById.values());
 
-        List<Integer> shuffledStudentIds = new ArrayList<>(studentsById.keySet());
-        Collections.shuffle(shuffledStudentIds);
+        List<Map.Entry<Integer, String>> shuffledStudentEntries = new ArrayList<>(studentsById.entrySet());
+        Collections.shuffle(shuffledStudentEntries);
 
-        List<String> shuffledStudents = shuffledStudentIds.stream()
-          .map(id -> studentsById.get(id))
-          .collect(Collectors.toList());
+        List<String> shuffledStudents = shuffledStudentEntries.stream()
+                .map(Map.Entry::getValue)
+                .collect(Collectors.toList());
 
         System.out.println("Students after shuffling");
         System.out.println(shuffledStudents);