From 956660497a08fda46057c0218d33e928a939bc50 Mon Sep 17 00:00:00 2001
From: Sam Gardner <samgardner909@gmail.com>
Date: Fri, 12 May 2023 11:58:08 +0100
Subject: [PATCH] BAEL-6334 Add example code for checking if a list element is
 in another list

---
 .../core-java-collections-list-5/pom.xml      | 13 ++++
 .../main/java/com/baeldung/list/Country.java  | 11 +++
 .../ListContainsElementFromOtherListTest.java | 68 +++++++++++++++++++
 3 files changed, 92 insertions(+)
 create mode 100644 core-java-modules/core-java-collections-list-5/src/main/java/com/baeldung/list/Country.java
 create mode 100644 core-java-modules/core-java-collections-list-5/src/test/java/com/baeldung/java/list/ListContainsElementFromOtherListTest.java

diff --git a/core-java-modules/core-java-collections-list-5/pom.xml b/core-java-modules/core-java-collections-list-5/pom.xml
index b51dda4091..3c734b8922 100644
--- a/core-java-modules/core-java-collections-list-5/pom.xml
+++ b/core-java-modules/core-java-collections-list-5/pom.xml
@@ -24,6 +24,19 @@
             <artifactId>commons-lang3</artifactId>
             <version>${commons-lang3.version}</version>
         </dependency>
+        <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-collections4 -->
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>4.4</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>1.18.26</version>
+            <scope>provided</scope>
+        </dependency>
     </dependencies>
 
     <properties>
diff --git a/core-java-modules/core-java-collections-list-5/src/main/java/com/baeldung/list/Country.java b/core-java-modules/core-java-collections-list-5/src/main/java/com/baeldung/list/Country.java
new file mode 100644
index 0000000000..354aeca2d3
--- /dev/null
+++ b/core-java-modules/core-java-collections-list-5/src/main/java/com/baeldung/list/Country.java
@@ -0,0 +1,11 @@
+package com.baeldung.list;
+
+import lombok.Data;
+
+@Data
+public class Country {
+
+    private final String name;
+    private final String capital;
+
+}
diff --git a/core-java-modules/core-java-collections-list-5/src/test/java/com/baeldung/java/list/ListContainsElementFromOtherListTest.java b/core-java-modules/core-java-collections-list-5/src/test/java/com/baeldung/java/list/ListContainsElementFromOtherListTest.java
new file mode 100644
index 0000000000..e69cc733ee
--- /dev/null
+++ b/core-java-modules/core-java-collections-list-5/src/test/java/com/baeldung/java/list/ListContainsElementFromOtherListTest.java
@@ -0,0 +1,68 @@
+package com.baeldung.java.list;
+
+import static java.util.stream.Collectors.toSet;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.commons.collections4.CollectionUtils;
+import org.junit.Test;
+
+import com.baeldung.list.Country;
+
+public class ListContainsElementFromOtherListTest {
+
+    final private List<String> listOfLetters = Arrays.asList("a", "b", "c", "d");
+    final private List<String> listOfLettersWithOverlap = Arrays.asList("d", "e", "f", "g");
+    final private List<String> listOfCities = Arrays.asList("London", "Berlin", "Paris", "Brussels");
+
+    @Test
+    public void givenWholeValuesToCompare_whenUsingCollectionsDisjoint_thenDetectElementsInTwoLists() {
+        boolean shouldBeTrue = !Collections.disjoint(listOfLetters, listOfLettersWithOverlap);
+        assertTrue(shouldBeTrue);
+
+        boolean shouldBeFalse = !Collections.disjoint(listOfLetters, listOfCities);
+        assertFalse(shouldBeFalse);
+    }
+
+    @Test
+    public void givenWholeValuesToCompare_whenUsingStreams_thenDetectElementsInTwoLists() {
+        boolean shouldBeTrue = listOfLetters.stream()
+          .anyMatch(listOfLettersWithOverlap::contains);
+        assertTrue(shouldBeTrue);
+
+        boolean shouldBeFalse = listOfLetters.stream()
+          .anyMatch(listOfCities::contains);
+        assertFalse(shouldBeFalse);
+    }
+
+    @Test
+    public void givenWholeValuesToCompare_whenUsingApacheCollectionUtils_thenDetectElementsInTwoLists() {
+        boolean shouldBeTrue = CollectionUtils.containsAny(listOfLetters, listOfLettersWithOverlap);
+        assertTrue(shouldBeTrue);
+
+        boolean shouldBeFalse = CollectionUtils.containsAny(listOfLetters, listOfCities);
+        assertFalse(shouldBeFalse);
+    }
+
+    @Test
+    public void givenWholePorpertiesInObjectsToCompare_whenUsingStreams_thenDetectElementsInTwoLists() {
+        Country france = new Country("France", "Paris");
+        Country belgium = new Country("Belgium", "Brussels");
+        Country spain = new Country("Spain", "Madrid");
+        List<Country> franceAndBelgium = Arrays.asList(france, belgium);
+        List<Country> belgiumAndSpain = Arrays.asList(belgium, spain);
+
+        boolean shouldBeTrue = franceAndBelgium.stream()
+          .map(Country::getCapital)
+          .anyMatch(belgiumAndSpain.stream()
+            .map(Country::getCapital)
+            .collect(toSet())::contains);
+
+        assertTrue(shouldBeTrue);
+    }
+
+}