diff --git a/core-java-modules/core-java-11-2/README.md b/core-java-modules/core-java-11-2/README.md index f65a043819..d77bf748a8 100644 --- a/core-java-modules/core-java-11-2/README.md +++ b/core-java-modules/core-java-11-2/README.md @@ -4,4 +4,5 @@ This module contains articles about Java 11 core features ### Relevant articles - [Guide to Java 8 Optional](https://www.baeldung.com/java-optional) +- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors) diff --git a/core-java-modules/core-java-11-2/pom.xml b/core-java-modules/core-java-11-2/pom.xml index d20b0f23f0..e2b129ae00 100644 --- a/core-java-modules/core-java-11-2/pom.xml +++ b/core-java-modules/core-java-11-2/pom.xml @@ -17,6 +17,11 @@ + + com.google.guava + guava + ${guava.version} + org.assertj assertj-core @@ -42,6 +47,7 @@ 11 11 + 29.0-jre 3.17.2 diff --git a/core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/collectors/Java8CollectorsUnitTest.java b/core-java-modules/core-java-11-2/src/test/java/com/baeldung/collectors/Java8CollectorsUnitTest.java similarity index 87% rename from core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/collectors/Java8CollectorsUnitTest.java rename to core-java-modules/core-java-11-2/src/test/java/com/baeldung/collectors/Java8CollectorsUnitTest.java index 6afc9f4182..7990b1fdb7 100644 --- a/core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/collectors/Java8CollectorsUnitTest.java +++ b/core-java-modules/core-java-11-2/src/test/java/com/baeldung/collectors/Java8CollectorsUnitTest.java @@ -1,18 +1,11 @@ -package com.baeldung.streams.collectors; +package com.baeldung.collectors; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableSet; import com.google.common.collect.Sets; import org.junit.Test; -import java.util.Arrays; -import java.util.Comparator; -import java.util.DoubleSummaryStatistics; -import java.util.LinkedList; -import java.util.List; -import java.util.Map; -import java.util.Optional; -import java.util.Set; +import java.util.*; import java.util.function.BiConsumer; import java.util.function.BinaryOperator; import java.util.function.Function; @@ -20,19 +13,7 @@ import java.util.function.Supplier; import java.util.stream.Collector; import static com.google.common.collect.Sets.newHashSet; -import static java.util.stream.Collectors.averagingDouble; -import static java.util.stream.Collectors.collectingAndThen; -import static java.util.stream.Collectors.counting; -import static java.util.stream.Collectors.groupingBy; -import static java.util.stream.Collectors.joining; -import static java.util.stream.Collectors.maxBy; -import static java.util.stream.Collectors.partitioningBy; -import static java.util.stream.Collectors.summarizingDouble; -import static java.util.stream.Collectors.summingDouble; -import static java.util.stream.Collectors.toCollection; -import static java.util.stream.Collectors.toList; -import static java.util.stream.Collectors.toMap; -import static java.util.stream.Collectors.toSet; +import static java.util.stream.Collectors.*; import static org.assertj.core.api.Assertions.assertThat; import static org.assertj.core.api.Assertions.assertThatThrownBy; @@ -48,6 +29,14 @@ public class Java8CollectorsUnitTest { assertThat(result).containsAll(givenList); } + @Test + public void whenCollectingToUnmodifiableList_shouldCollectToUnmodifiableList() { + final List result = givenList.stream().collect(toUnmodifiableList()); + + assertThatThrownBy(() -> result.add("foo")) + .isInstanceOf(UnsupportedOperationException.class); + } + @Test public void whenCollectingToSet_shouldCollectToSet() throws Exception { final Set result = givenList.stream().collect(toSet()); @@ -55,6 +44,14 @@ public class Java8CollectorsUnitTest { assertThat(result).containsAll(givenList); } + @Test + public void whenCollectingToUnmodifiableSet_shouldCollectToUnmodifiableSet() { + final Set result = givenList.stream().collect(toUnmodifiableSet()); + + assertThatThrownBy(() -> result.add("foo")) + .isInstanceOf(UnsupportedOperationException.class); + } + @Test public void givenContainsDuplicateElements_whenCollectingToSet_shouldAddDuplicateElementsOnlyOnce() throws Exception { final Set result = listWithDuplicates.stream().collect(toSet()); @@ -84,6 +81,15 @@ public class Java8CollectorsUnitTest { assertThat(result).containsEntry("a", 1).containsEntry("bb", 2).containsEntry("ccc", 3).containsEntry("dd", 2); } + @Test + public void whenCollectingToUnmodifiableMap_shouldCollectToUnmodifiableMap() { + final Map result = givenList.stream() + .collect(toUnmodifiableMap(Function.identity(), String::length)); + + assertThatThrownBy(() -> result.put("foo", 3)) + .isInstanceOf(UnsupportedOperationException.class); + } + @Test public void whenCollectingToMapwWithDuplicates_shouldCollectToMapMergingTheIdenticalItems() throws Exception { final Map result = listWithDuplicates.stream().collect( diff --git a/core-java-modules/core-java-streams-3/README.md b/core-java-modules/core-java-streams-3/README.md index 65713aa04f..9adde005e6 100644 --- a/core-java-modules/core-java-streams-3/README.md +++ b/core-java-modules/core-java-streams-3/README.md @@ -6,7 +6,6 @@ This module contains articles about the Stream API in Java. - [The Difference Between map() and flatMap()](https://www.baeldung.com/java-difference-map-and-flatmap) - [How to Use if/else Logic in Java 8 Streams](https://www.baeldung.com/java-8-streams-if-else-logic) - [The Difference Between Collection.stream().forEach() and Collection.forEach()](https://www.baeldung.com/java-collection-stream-foreach) -- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors) - [Primitive Type Streams in Java 8](https://www.baeldung.com/java-8-primitive-streams) - [Debugging Java 8 Streams with IntelliJ](https://www.baeldung.com/intellij-debugging-java-streams) - [Add BigDecimals using the Stream API](https://www.baeldung.com/java-stream-add-bigdecimals)