BAEL-4959 iterating over the Set (#10864)

2021-06-06 20:36:01 +02:00
parent b2516200f2
commit e9cf19c324
2 changed files with 80 additions and 0 deletions
--- a/java-collections-conversions-2/src/test/java/com/baeldung/setiteration/SetIteration.java
+++ b/java-collections-conversions-2/src/test/java/com/baeldung/setiteration/SetIteration.java
@@ -0,0 +1,74 @@
+package com.baeldung.setiteration;
+
+import com.google.common.collect.Sets;
+import io.vavr.collection.Stream;
+import org.junit.jupiter.api.Test;
+
+import java.util.Iterator;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+class SetIteration {
+
+    @Test
+    void givenSet_whenIteratorUsed_shouldIterateOverElements() {
+        // given
+        Set<String> names = Sets.newHashSet("Tom", "Jane", "Karen");
+
+        // when
+        Iterator<String> namesIterator1 = names.iterator();
+        Iterator<String> namesIterator2 = names.iterator();
+
+        // then
+        namesIterator1.forEachRemaining(System.out::println);
+        while(namesIterator2.hasNext()) {
+            System.out.println(namesIterator2.next());
+        }
+    }
+
+    @Test
+    void givenSet_whenStreamUsed_shouldIterateOverElements() {
+        // given
+        Set<String> names = Sets.newHashSet("Tom", "Jane", "Karen");
+
+        // when & then
+        String namesJoined = names.stream()
+                .map(String::toUpperCase)
+                .peek(System.out::println)
+                .collect(Collectors.joining());
+    }
+
+    @Test
+    void givenSet_whenEnhancedLoopUsed_shouldIterateOverElements() {
+        // given
+        Set<String> names = Sets.newHashSet("Tom", "Jane", "Karen");
+
+        // when & then
+        for (String name : names) {
+            System.out.println(name);
+        }
+    }
+
+    @Test
+    void givenSet_whenMappedToArray_shouldIterateOverElements() {
+        // given
+        Set<String> names = Sets.newHashSet("Tom", "Jane", "Karen");
+
+        // when & then
+        Object[] namesArray = names.toArray();
+        for (int i = 0; i < namesArray.length; i++) {
+            System.out.println(i + ": " + namesArray[i]);
+        }
+    }
+
+    @Test
+    void givenSet_whenZippedWithIndex_shouldIterateOverElements() {
+        // given
+        Set<String> names = Sets.newHashSet("Tom", "Jane", "Karen");
+
+        // when & then
+        Stream.ofAll(names)
+                .zipWithIndex()
+                .forEach(t -> System.out.println(t._2() + ": " + t._1()));
+    }
+}