JAVA-1188: Moved modules to core-java-modules
This commit is contained in:
sampadawagde
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## Java Collections Cookbooks and Examples
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This module contains articles about Map data structures in Java.
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### Relevant Articles:
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- [Guide to the Guava BiMap](https://www.baeldung.com/guava-bimap)
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- [A Guide to Java HashMap](https://www.baeldung.com/java-hashmap)
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- [A Guide to LinkedHashMap in Java](https://www.baeldung.com/java-linked-hashmap)
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- [A Guide to TreeMap in Java](https://www.baeldung.com/java-treemap)
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- [How to Store Duplicate Keys in a Map in Java?](https://www.baeldung.com/java-map-duplicate-keys)
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- [Get the Key for a Value from a Java Map](https://www.baeldung.com/java-map-key-from-value)
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- [How to Check If a Key Exists in a Map](https://www.baeldung.com/java-map-key-exists)
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- [Immutable Map Implementations in Java](https://www.baeldung.com/java-immutable-maps)
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- [Guide to Apache Commons MultiValuedMap](https://www.baeldung.com/apache-commons-multi-valued-map)
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- [The Java HashMap Under the Hood](https://www.baeldung.com/java-hashmap-advanced)
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- More articles: [[next -->]](/core-java-collections-maps-2)
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@@ -0,0 +1,35 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<artifactId>core-java-collections-maps</artifactId>
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<version>0.1.0-SNAPSHOT</version>
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<name>core-java-collections-maps</name>
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<packaging>jar</packaging>
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<parent>
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<groupId>com.baeldung</groupId>
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<artifactId>parent-java</artifactId>
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<version>0.0.1-SNAPSHOT</version>
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<relativePath>../../parent-java</relativePath>
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</parent>
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<dependencies>
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<dependency>
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<groupId>org.apache.commons</groupId>
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<artifactId>commons-collections4</artifactId>
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<version>${commons-collections4.version}</version>
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</dependency>
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<dependency>
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<groupId>org.assertj</groupId>
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<artifactId>assertj-core</artifactId>
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<version>${assertj.version}</version>
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<scope>test</scope>
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</dependency>
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</dependencies>
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<properties>
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<commons-collections4.version>4.1</commons-collections4.version>
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<assertj.version>3.6.1</assertj.version>
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</properties>
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</project>
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+44
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/**
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*
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*/
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package com.baeldung.map;
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import java.util.HashSet;
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import java.util.Map;
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import java.util.Map.Entry;
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import java.util.Set;
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import java.util.stream.Stream;
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/**
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* @author swpraman
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*
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*/
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public class MapUtil {
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public static <K, V> Stream<K> keys(Map<K, V> map, V value) {
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return map.entrySet()
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.stream()
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.filter(entry -> value.equals(entry.getValue()))
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.map(Map.Entry::getKey);
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}
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public static <K, V> Set<K> getKeys(Map<K, V> map, V value) {
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Set<K> keys = new HashSet<>();
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for (Entry<K, V> entry : map.entrySet()) {
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if (entry.getValue().equals(value)) {
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keys.add(entry.getKey());
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}
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}
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return keys;
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}
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public static <K, V> K getKey(Map<K, V> map, V value) {
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for (Entry<K, V> entry : map.entrySet()) {
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if (entry.getValue().equals(value)) {
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return entry.getKey();
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}
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}
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return null;
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}
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}
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+64
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package com.baeldung.map;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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public class MyKey {
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private static final Logger LOG = LoggerFactory.getLogger(MyKey.class);
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private String name;
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private int id;
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public MyKey(int id, String name) {
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this.id = id;
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this.name = name;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public int getId() {
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return id;
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}
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public void setId(int id) {
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this.id = id;
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}
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@Override
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public int hashCode() {
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LOG.debug("Calling hashCode()");
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return id;
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}
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@Override
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public String toString() {
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return "MyKey [name=" + name + ", id=" + id + "]";
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}
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@Override
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public boolean equals(Object obj) {
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LOG.debug("Calling equals() for key: " + obj);
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if (this == obj)
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return true;
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if (obj == null)
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return false;
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if (getClass() != obj.getClass())
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return false;
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MyKey other = (MyKey) obj;
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if (id != other.id)
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return false;
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if (name == null) {
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if (other.name != null)
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return false;
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} else if (!name.equals(other.name))
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return false;
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return true;
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}
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}
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+23
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package com.baeldung.map;
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import java.util.LinkedHashMap;
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import java.util.Map;
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public class MyLinkedHashMap<K, V> extends LinkedHashMap<K, V> {
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/**
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*
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*/
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private static final long serialVersionUID = 1L;
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private static final int MAX_ENTRIES = 5;
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public MyLinkedHashMap(int initialCapacity, float loadFactor, boolean accessOrder) {
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super(initialCapacity, loadFactor, accessOrder);
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}
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@Override
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protected boolean removeEldestEntry(Map.Entry eldest) {
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return size() > MAX_ENTRIES;
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}
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}
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@@ -0,0 +1,13 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<configuration>
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<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
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<encoder>
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<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
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</pattern>
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</encoder>
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</appender>
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<root level="INFO">
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<appender-ref ref="STDOUT" />
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</root>
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</configuration>
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+120
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package com.baeldung.guava;
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import static org.junit.Assert.*;
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import java.util.HashMap;
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import java.util.Map;
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import org.junit.Test;
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import com.google.common.collect.BiMap;
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import com.google.common.collect.EnumHashBiMap;
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import com.google.common.collect.HashBiMap;
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import com.google.common.collect.ImmutableBiMap;
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public class GuavaBiMapUnitTest {
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@Test
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public void whenQueryByValue_returnsKey() {
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final BiMap<String, String> capitalCountryBiMap = HashBiMap.create();
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capitalCountryBiMap.put("New Delhi", "India");
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capitalCountryBiMap.put("Washingon, D.C.", "USA");
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capitalCountryBiMap.put("Moscow", "Russia");
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final String countryCapitalName = capitalCountryBiMap.inverse().get("India");
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assertEquals("New Delhi", countryCapitalName);
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}
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@Test
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public void whenCreateBiMapFromExistingMap_returnsKey() {
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final Map<String, String> capitalCountryMap = new HashMap<>();
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capitalCountryMap.put("New Delhi", "India");
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capitalCountryMap.put("Washingon, D.C.", "USA");
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capitalCountryMap.put("Moscow", "Russia");
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final BiMap<String, String> capitalCountryBiMap = HashBiMap.create(capitalCountryMap);
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final String countryCapitalName = capitalCountryBiMap.inverse().get("India");
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assertEquals("New Delhi", countryCapitalName);
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}
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@Test
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public void whenQueryByKey_returnsValue() {
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final BiMap<String, String> capitalCountryBiMap = HashBiMap.create();
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capitalCountryBiMap.put("New Delhi", "India");
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capitalCountryBiMap.put("Washingon, D.C.", "USA");
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capitalCountryBiMap.put("Moscow", "Russia");
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assertEquals("USA", capitalCountryBiMap.get("Washingon, D.C."));
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}
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@Test(expected = IllegalArgumentException.class)
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public void whenSameValueIsPresent_throwsException() {
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final BiMap<String, String> capitalCountryBiMap = HashBiMap.create();
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capitalCountryBiMap.put("New Delhi", "India");
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capitalCountryBiMap.put("Washingon, D.C.", "USA");
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capitalCountryBiMap.put("Moscow", "Russia");
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capitalCountryBiMap.put("Trump", "USA");
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}
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@Test
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public void givenSameValueIsPresent_whenForcePut_completesSuccessfully() {
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final BiMap<String, String> capitalCountryBiMap = HashBiMap.create();
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capitalCountryBiMap.put("New Delhi", "India");
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capitalCountryBiMap.put("Washingon, D.C.", "USA");
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capitalCountryBiMap.put("Moscow", "Russia");
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capitalCountryBiMap.forcePut("Trump", "USA");
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assertEquals("USA", capitalCountryBiMap.get("Trump"));
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assertEquals("Trump", capitalCountryBiMap.inverse().get("USA"));
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}
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@Test
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public void whenSameKeyIsPresent_replacesAlreadyPresent() {
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final BiMap<String, String> capitalCountryBiMap = HashBiMap.create();
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capitalCountryBiMap.put("New Delhi", "India");
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capitalCountryBiMap.put("Washingon, D.C.", "USA");
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capitalCountryBiMap.put("Moscow", "Russia");
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capitalCountryBiMap.put("Washingon, D.C.", "HongKong");
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assertEquals("HongKong", capitalCountryBiMap.get("Washingon, D.C."));
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}
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@Test
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public void whenUsingImmutableBiMap_allowsPutSuccessfully() {
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final BiMap<String, String> capitalCountryBiMap = new ImmutableBiMap.Builder<String, String>().put("New Delhi", "India").put("Washingon, D.C.", "USA").put("Moscow", "Russia").build();
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assertEquals("USA", capitalCountryBiMap.get("Washingon, D.C."));
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenUsingImmutableBiMap_doesntAllowRemove() {
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final BiMap<String, String> capitalCountryBiMap = new ImmutableBiMap.Builder<String, String>().put("New Delhi", "India").put("Washingon, D.C.", "USA").put("Moscow", "Russia").build();
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capitalCountryBiMap.remove("New Delhi");
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenUsingImmutableBiMap_doesntAllowPut() {
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final BiMap<String, String> capitalCountryBiMap = new ImmutableBiMap.Builder<String, String>().put("New Delhi", "India").put("Washingon, D.C.", "USA").put("Moscow", "Russia").build();
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capitalCountryBiMap.put("New York", "USA");
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}
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private enum Operation {
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ADD, SUBTRACT, MULTIPLY, DIVIDE
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}
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@Test
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public void whenUsingEnumAsKeyInMap_replacesAlreadyPresent() {
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final BiMap<Operation, String> operationStringBiMap = EnumHashBiMap.create(Operation.class);
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operationStringBiMap.put(Operation.ADD, "Add");
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operationStringBiMap.put(Operation.SUBTRACT, "Subtract");
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operationStringBiMap.put(Operation.MULTIPLY, "Multiply");
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operationStringBiMap.put(Operation.DIVIDE, "Divide");
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assertEquals("Divide", operationStringBiMap.get(Operation.DIVIDE));
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}
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}
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+84
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package com.baeldung.map;
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import com.google.common.collect.ImmutableMap;
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import org.junit.jupiter.api.Test;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.Map;
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import static org.junit.jupiter.api.Assertions.*;
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public class ImmutableMapUnitTest {
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@Test
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public void whenCollectionsUnModifiableMapMethod_thenOriginalCollectionChangesReflectInUnmodifiableMap() {
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Map<String, String> mutableMap = new HashMap<>();
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mutableMap.put("USA", "North America");
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Map<String, String> unmodifiableMap = Collections.unmodifiableMap(mutableMap);
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assertThrows(UnsupportedOperationException.class, () -> unmodifiableMap.put("Canada", "North America"));
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mutableMap.remove("USA");
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assertFalse(unmodifiableMap.containsKey("USA"));
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mutableMap.put("Mexico", "North America");
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assertTrue(unmodifiableMap.containsKey("Mexico"));
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}
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@Test
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@SuppressWarnings("deprecation")
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public void whenGuavaImmutableMapFromCopyOfMethod_thenOriginalCollectionChangesDoNotReflectInImmutableMap() {
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Map<String, String> mutableMap = new HashMap<>();
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mutableMap.put("USA", "North America");
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ImmutableMap<String, String> immutableMap = ImmutableMap.copyOf(mutableMap);
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assertTrue(immutableMap.containsKey("USA"));
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assertThrows(UnsupportedOperationException.class, () -> immutableMap.put("Canada", "North America"));
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mutableMap.remove("USA");
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assertTrue(immutableMap.containsKey("USA"));
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mutableMap.put("Mexico", "North America");
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assertFalse(immutableMap.containsKey("Mexico"));
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}
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|
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@Test
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@SuppressWarnings("deprecation")
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public void whenGuavaImmutableMapFromBuilderMethod_thenOriginalCollectionChangesDoNotReflectInImmutableMap() {
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Map<String, String> mutableMap = new HashMap<>();
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mutableMap.put("USA", "North America");
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ImmutableMap<String, String> immutableMap = ImmutableMap.<String, String>builder()
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.putAll(mutableMap)
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.put("Costa Rica", "North America")
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.build();
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assertTrue(immutableMap.containsKey("USA"));
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assertTrue(immutableMap.containsKey("Costa Rica"));
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assertThrows(UnsupportedOperationException.class, () -> immutableMap.put("Canada", "North America"));
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mutableMap.remove("USA");
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assertTrue(immutableMap.containsKey("USA"));
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mutableMap.put("Mexico", "North America");
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assertFalse(immutableMap.containsKey("Mexico"));
|
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}
|
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|
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@Test
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@SuppressWarnings("deprecation")
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public void whenGuavaImmutableMapFromOfMethod_thenOriginalCollectionChangesDoNotReflectInImmutableMap() {
|
||||
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ImmutableMap<String, String> immutableMap = ImmutableMap.of("USA", "North America", "Costa Rica", "North America");
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assertTrue(immutableMap.containsKey("USA"));
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assertTrue(immutableMap.containsKey("Costa Rica"));
|
||||
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assertThrows(UnsupportedOperationException.class, () -> immutableMap.put("Canada", "North America"));
|
||||
}
|
||||
|
||||
}
|
||||
+27
@@ -0,0 +1,27 @@
|
||||
package com.baeldung.map;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
import java.util.Collections;
|
||||
import java.util.Map;
|
||||
|
||||
import static org.junit.Assert.*;
|
||||
|
||||
public class KeyCheckUnitTest {
|
||||
|
||||
@Test
|
||||
public void whenKeyIsPresent_thenContainsKeyReturnsTrue() {
|
||||
Map<String, String> map = Collections.singletonMap("key", "value");
|
||||
|
||||
assertTrue(map.containsKey("key"));
|
||||
assertFalse(map.containsKey("missing"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenKeyHasNullValue_thenGetStillWorks() {
|
||||
Map<String, String> map = Collections.singletonMap("nothing", null);
|
||||
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||||
assertTrue(map.containsKey("nothing"));
|
||||
assertNull(map.get("nothing"));
|
||||
}
|
||||
}
|
||||
+119
@@ -0,0 +1,119 @@
|
||||
package com.baeldung.map;
|
||||
|
||||
import com.google.common.collect.ArrayListMultimap;
|
||||
import com.google.common.collect.LinkedHashMultimap;
|
||||
import com.google.common.collect.Multimap;
|
||||
import com.google.common.collect.TreeMultimap;
|
||||
import org.apache.commons.collections4.MultiMap;
|
||||
import org.apache.commons.collections4.MultiMapUtils;
|
||||
import org.apache.commons.collections4.MultiValuedMap;
|
||||
import org.apache.commons.collections4.map.MultiValueMap;
|
||||
import org.apache.commons.collections4.multimap.ArrayListValuedHashMap;
|
||||
import org.apache.commons.collections4.multimap.HashSetValuedHashMap;
|
||||
import org.junit.Test;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
import java.util.*;
|
||||
|
||||
import static org.assertj.core.api.Assertions.assertThat;
|
||||
|
||||
public class MapMultipleValuesUnitTest {
|
||||
private static final Logger LOG = LoggerFactory.getLogger(MapMultipleValuesUnitTest.class);
|
||||
|
||||
@Test
|
||||
public void givenHashMap_whenPuttingTwice_thenReturningFirstValue() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
assertThat(map.put("key1", "value1")).isEqualTo(null);
|
||||
assertThat(map.put("key1", "value2")).isEqualTo("value1");
|
||||
assertThat(map.get("key1")).isEqualTo("value2");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenCollectionAsValue_whenPuttingTwice_thenReturningCollection() {
|
||||
Map<String, List<String>> map = new HashMap<>();
|
||||
List<String> list = new ArrayList<>();
|
||||
map.put("key1", list);
|
||||
map.get("key1").add("value1");
|
||||
map.get("key1").add("value2");
|
||||
assertThat(map.get("key1").get(0)).isEqualTo("value1");
|
||||
assertThat(map.get("key1").get(1)).isEqualTo("value2");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenCollectionAsValueAndJava8_whenPuttingTwice_thenReturningCollection() {
|
||||
Map<String, List<String>> map = new HashMap<>();
|
||||
map.computeIfAbsent("key1", k -> new ArrayList<>()).add("value1");
|
||||
map.computeIfAbsent("key1", k -> new ArrayList<>()).add("value2");
|
||||
assertThat(map.get("key1").get(0)).isEqualTo("value1");
|
||||
assertThat(map.get("key1").get(1)).isEqualTo("value2");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValueMap_whenPuttingTwice_thenReturningValues() {
|
||||
MultiMap<String, String> map = new MultiValueMap<>();
|
||||
map.put("key1", "value1");
|
||||
map.put("key1", "value2");
|
||||
assertThat((Collection<String>) map.get("key1"))
|
||||
.contains("value1", "value2");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenArrayListValuedHashMap_whenPuttingDoubleValues_thenReturningAllValues() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("key1", "value1");
|
||||
map.put("key1", "value2");
|
||||
map.put("key1", "value2");
|
||||
assertThat((Collection<String>) map.get("key1"))
|
||||
.containsExactly("value1", "value2", "value2");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashSetValuedHashMap_whenPuttingTwiceTheSame_thenReturningOneValue() {
|
||||
MultiValuedMap<String, String> map = new HashSetValuedHashMap<>();
|
||||
map.put("key1", "value1");
|
||||
map.put("key1", "value1");
|
||||
assertThat((Collection<String>) map.get("key1"))
|
||||
.containsExactly("value1");
|
||||
}
|
||||
|
||||
@Test(expected = UnsupportedOperationException.class)
|
||||
public void givenUnmodifiableMultiValuedMap_whenInserting_thenThrowingException() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("key1", "value1");
|
||||
map.put("key1", "value2");
|
||||
MultiValuedMap<String, String> immutableMap =
|
||||
MultiMapUtils.unmodifiableMultiValuedMap(map);
|
||||
immutableMap.put("key1", "value3");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenArrayListMultiMap_whenInserting_thenCorrectOutput() {
|
||||
Multimap<String, String> map = ArrayListMultimap.create();
|
||||
map.put("key1", "value2");
|
||||
map.put("key1", "value1");
|
||||
assertThat((Collection<String>) map.get("key1"))
|
||||
.containsExactly("value2", "value1");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenLinkedHashMultiMap_whenInserting_thenReturningValuesInInsertionOrder() {
|
||||
Multimap<String, String> map = LinkedHashMultimap.create();
|
||||
map.put("key1", "value3");
|
||||
map.put("key1", "value1");
|
||||
map.put("key1", "value2");
|
||||
assertThat((Collection<String>) map.get("key1"))
|
||||
.containsExactly("value3", "value1", "value2");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenTreeMultimap_whenInserting_thenReturningValuesInNaturalOrder() {
|
||||
Multimap<String, String> map = TreeMultimap.create();
|
||||
map.put("key1", "value3");
|
||||
map.put("key1", "value1");
|
||||
map.put("key1", "value2");
|
||||
assertThat((Collection<String>) map.get("key1"))
|
||||
.containsExactly("value1", "value2", "value3");
|
||||
}
|
||||
|
||||
}
|
||||
+336
File diff suppressed because it is too large
Load Diff
+103
@@ -0,0 +1,103 @@
|
||||
/**
|
||||
*
|
||||
*/
|
||||
package com.baeldung.map;
|
||||
|
||||
import com.google.common.collect.HashBiMap;
|
||||
import org.apache.commons.collections4.BidiMap;
|
||||
import org.apache.commons.collections4.bidimap.DualHashBidiMap;
|
||||
import org.junit.Test;
|
||||
|
||||
import java.util.Arrays;
|
||||
import java.util.HashMap;
|
||||
import java.util.HashSet;
|
||||
import java.util.Map;
|
||||
import java.util.stream.Collectors;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
|
||||
/**
|
||||
* @author swpraman
|
||||
*
|
||||
*/
|
||||
public class MapUtilUnitTest {
|
||||
|
||||
|
||||
@Test
|
||||
public void whenUsingImperativeWayForSingleKey_shouldReturnSingleKey() {
|
||||
Map<String, String> capitalCountryMap = new HashMap<>();
|
||||
capitalCountryMap.put("Tokyo", "Japan");
|
||||
capitalCountryMap.put("New Delhi", "India");
|
||||
assertEquals("New Delhi", MapUtil.getKey(capitalCountryMap, "India"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingImperativeWayForAllKeys_shouldReturnAllKeys() {
|
||||
Map<String, String> capitalCountryMap = new HashMap<>();
|
||||
capitalCountryMap.put("Tokyo", "Japan");
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
capitalCountryMap.put("Cape Town", "South Africa");
|
||||
capitalCountryMap.put("Pretoria", "South Africa");
|
||||
capitalCountryMap.put("Bloemfontein", "South Africa");
|
||||
|
||||
assertEquals(new HashSet<String>(Arrays.asList(
|
||||
new String[] {"Cape Town", "Pretoria", "Bloemfontein"})),
|
||||
MapUtil.getKeys(capitalCountryMap, "South Africa"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingFunctionalWayForSingleKey_shouldReturnSingleKey() {
|
||||
Map<String, String> capitalCountryMap = new HashMap<>();
|
||||
capitalCountryMap.put("Tokyo", "Japan");
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
assertEquals("Berlin", MapUtil.keys(capitalCountryMap, "Germany").findFirst().get());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingFunctionalWayForAllKeys_shouldReturnAllKeys() {
|
||||
Map<String, String> capitalCountryMap = new HashMap<>();
|
||||
capitalCountryMap.put("Tokyo", "Japan");
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
capitalCountryMap.put("Cape Town", "South Africa");
|
||||
capitalCountryMap.put("Pretoria", "South Africa");
|
||||
capitalCountryMap.put("Bloemfontein", "South Africa");
|
||||
assertEquals(new HashSet<String>(Arrays.asList(
|
||||
new String[] {"Cape Town", "Pretoria", "Bloemfontein"})),
|
||||
MapUtil.keys(capitalCountryMap, "South Africa").collect(Collectors.toSet()));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingBidiMap_shouldReturnKey() {
|
||||
BidiMap<String, String> capitalCountryMap = new DualHashBidiMap<String, String>();
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
capitalCountryMap.put("Cape Town", "South Africa");
|
||||
assertEquals("Berlin", capitalCountryMap.getKey("Germany"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingBidiMapAddDuplicateValue_shouldRemoveOldEntry() {
|
||||
BidiMap<String, String> capitalCountryMap = new DualHashBidiMap<String, String>();
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
capitalCountryMap.put("Cape Town", "South Africa");
|
||||
capitalCountryMap.put("Pretoria", "South Africa");
|
||||
assertEquals("Pretoria", capitalCountryMap.getKey("South Africa"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingBiMap_shouldReturnKey() {
|
||||
HashBiMap<String, String> capitalCountryMap = HashBiMap.create();
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
capitalCountryMap.put("Cape Town", "South Africa");
|
||||
assertEquals("Berlin", capitalCountryMap.inverse().get("Germany"));
|
||||
}
|
||||
|
||||
@Test(expected=IllegalArgumentException.class)
|
||||
public void whenUsingBiMapAddDuplicateValue_shouldThrowException() {
|
||||
HashBiMap<String, String> capitalCountryMap = HashBiMap.create();
|
||||
capitalCountryMap.put("Berlin", "Germany");
|
||||
capitalCountryMap.put("Cape Town", "South Africa");
|
||||
capitalCountryMap.put("Pretoria", "South Africa");
|
||||
assertEquals("Berlin", capitalCountryMap.inverse().get("Germany"));
|
||||
}
|
||||
|
||||
}
|
||||
+227
@@ -0,0 +1,227 @@
|
||||
package com.baeldung.map;
|
||||
|
||||
import org.apache.commons.collections4.MultiMapUtils;
|
||||
import org.apache.commons.collections4.MultiSet;
|
||||
import org.apache.commons.collections4.MultiValuedMap;
|
||||
import org.apache.commons.collections4.multimap.ArrayListValuedHashMap;
|
||||
import org.apache.commons.collections4.multimap.HashSetValuedHashMap;
|
||||
import org.junit.Test;
|
||||
|
||||
import java.util.Arrays;
|
||||
import java.util.Collection;
|
||||
import java.util.Map;
|
||||
import java.util.Map.Entry;
|
||||
import java.util.Set;
|
||||
|
||||
import static org.assertj.core.api.Assertions.assertThat;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
import static org.junit.jupiter.api.Assertions.assertEquals;
|
||||
import static org.junit.jupiter.api.Assertions.assertFalse;
|
||||
|
||||
public class MultiValuedMapUnitTest {
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenPuttingMultipleValuesUsingPutMethod_thenReturningAllValues() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
|
||||
assertThat((Collection<String>) map.get("fruits")).containsExactly("apple", "orange");
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenPuttingMultipleValuesUsingPutAllMethod_thenReturningAllValues() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
|
||||
map.putAll("vehicles", Arrays.asList("car", "bike"));
|
||||
|
||||
assertThat((Collection<String>) map.get("vehicles")).containsExactly("car", "bike");
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenGettingValueUsingGetMethod_thenReturningValue() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
|
||||
map.put("fruits", "apple");
|
||||
|
||||
assertThat((Collection<String>) map.get("fruits")).containsExactly("apple");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingEntriesMethod_thenReturningMappings() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
|
||||
Collection<Entry<String, String>> entries = (Collection<Entry<String, String>>) map.entries();
|
||||
|
||||
for(Map.Entry<String,String> entry : entries) {
|
||||
assertThat(entry.getKey()).contains("fruits");
|
||||
assertTrue(entry.getValue().equals("apple") || entry.getValue().equals("orange") );
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingKeysMethod_thenReturningAllKeys() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
MultiSet<String> keys = map.keys();
|
||||
|
||||
assertThat((keys)).contains("fruits", "vehicles");
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingKeySetMethod_thenReturningAllKeys() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
Set<String> keys = map.keySet();
|
||||
|
||||
assertThat(keys).contains("fruits", "vehicles");
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingValuesMethod_thenReturningAllValues() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
assertThat(((Collection<String>) map.values())).contains("apple", "orange", "car", "bike");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingRemoveMethod_thenReturningUpdatedMap() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
assertThat(((Collection<String>) map.values())).contains("apple", "orange", "car", "bike");
|
||||
|
||||
map.remove("fruits");
|
||||
|
||||
assertThat(((Collection<String>) map.values())).contains("car", "bike");
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingRemoveMappingMethod_thenReturningUpdatedMapAfterMappingRemoved() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
assertThat(((Collection<String>) map.values())).contains("apple", "orange", "car", "bike");
|
||||
|
||||
map.removeMapping("fruits", "apple");
|
||||
|
||||
assertThat(((Collection<String>) map.values())).contains("orange", "car", "bike");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingClearMethod_thenReturningEmptyMap() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
assertThat(((Collection<String>) map.values())).contains("apple", "orange", "car", "bike");
|
||||
|
||||
map.clear();
|
||||
|
||||
assertTrue(map.isEmpty());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingContainsKeyMethod_thenReturningTrue() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
assertTrue(map.containsKey("fruits"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingContainsValueMethod_thenReturningTrue() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
assertTrue(map.containsValue("orange"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingIsEmptyMethod_thenReturningFalse() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
assertFalse(map.isEmpty());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMultiValuesMap_whenUsingSizeMethod_thenReturningElementCount() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("vehicles", "car");
|
||||
map.put("vehicles", "bike");
|
||||
|
||||
assertEquals(4, map.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenArrayListValuedHashMap_whenPuttingDoubleValues_thenReturningAllValues() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
map.put("fruits", "orange");
|
||||
|
||||
assertThat((Collection<String>) map.get("fruits")).containsExactly("apple", "orange", "orange");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashSetValuedHashMap_whenPuttingTwiceTheSame_thenReturningOneValue() {
|
||||
MultiValuedMap<String, String> map = new HashSetValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "apple");
|
||||
|
||||
assertThat((Collection<String>) map.get("fruits")).containsExactly("apple");
|
||||
}
|
||||
|
||||
@Test(expected = UnsupportedOperationException.class)
|
||||
public void givenUnmodifiableMultiValuedMap_whenInserting_thenThrowingException() {
|
||||
MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
|
||||
map.put("fruits", "apple");
|
||||
map.put("fruits", "orange");
|
||||
MultiValuedMap<String, String> immutableMap = MultiMapUtils.unmodifiableMultiValuedMap(map);
|
||||
|
||||
immutableMap.put("fruits", "banana");
|
||||
|
||||
}
|
||||
|
||||
|
||||
}
|
||||
Reference in New Issue
Block a user