[BAEL-9550] - Moved articles and codes from core-java-collections module to java-collections-convversions and java-collections-maps module
This commit is contained in:
amit2103
@@ -0,0 +1,44 @@
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/**
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*
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*/
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package com.baeldung.java.map;
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import java.util.HashSet;
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import java.util.Map;
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import java.util.Set;
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import java.util.Map.Entry;
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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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@@ -0,0 +1,64 @@
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package com.baeldung.java.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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@@ -0,0 +1,23 @@
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package com.baeldung.java.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 +1,80 @@
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package com.baeldung.java.map.initialize;
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import java.util.AbstractMap;
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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 java.util.stream.Collectors;
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import java.util.stream.Stream;
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public class MapInitializer {
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public static Map<String, String> articleMapOne;
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static {
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articleMapOne = new HashMap<>();
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articleMapOne.put("ar01", "Intro to Map");
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articleMapOne.put("ar02", "Some article");
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}
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public static Map<String, String> createSingletonMap() {
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Map<String, String> passwordMap = Collections.singletonMap("username1", "password1");
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return passwordMap;
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}
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public Map<String, String> createEmptyMap() {
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Map<String, String> emptyMap = Collections.emptyMap();
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return emptyMap;
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}
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public Map<String, String> createUsingDoubleBrace() {
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Map<String, String> doubleBraceMap = new HashMap<String, String>() {
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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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{
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put("key1", "value1");
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put("key2", "value2");
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}
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};
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return doubleBraceMap;
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}
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public Map<String, String> createMapUsingStreamStringArray() {
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Map<String, String> map = Stream.of(new String[][] { { "Hello", "World" }, { "John", "Doe" }, })
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.collect(Collectors.toMap(data -> data[0], data -> data[1]));
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return map;
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}
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public Map<String, Integer> createMapUsingStreamObjectArray() {
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Map<String, Integer> map = Stream.of(new Object[][] { { "data1", 1 }, { "data2", 2 }, })
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.collect(Collectors.toMap(data -> (String) data[0], data -> (Integer) data[1]));
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return map;
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}
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public Map<String, Integer> createMapUsingStreamSimpleEntry() {
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Map<String, Integer> map = Stream.of(new AbstractMap.SimpleEntry<>("idea", 1), new AbstractMap.SimpleEntry<>("mobile", 2))
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.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
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return map;
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}
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public Map<String, Integer> createMapUsingStreamSimpleImmutableEntry() {
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Map<String, Integer> map = Stream.of(new AbstractMap.SimpleImmutableEntry<>("idea", 1), new AbstractMap.SimpleImmutableEntry<>("mobile", 2))
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.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
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return map;
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}
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public Map<String, String> createImmutableMapWithStreams() {
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Map<String, String> map = Stream.of(new String[][] { { "Hello", "World" }, { "John", "Doe" }, })
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.collect(Collectors.collectingAndThen(Collectors.toMap(data -> data[0], data -> data[1]), Collections::<String, String> unmodifiableMap));
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return map;
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}
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}
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@@ -0,0 +1,74 @@
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package com.baeldung.map.iteration;
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import java.util.HashMap;
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import java.util.Iterator;
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import java.util.Map;
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public class MapIteration {
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public static void main(String[] args) {
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MapIteration mapIteration = new MapIteration();
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Map<String, Integer> map = new HashMap<>();
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map.put("One", 1);
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map.put("Three", 3);
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map.put("Two", 2);
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System.out.println("Iterating Keys of Map Using KeySet");
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mapIteration.iterateKeys(map);
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System.out.println("Iterating Map Using Entry Set");
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mapIteration.iterateUsingEntrySet(map);
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System.out.println("Iterating Using Iterator and Map Entry");
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mapIteration.iterateUsingIteratorAndEntry(map);
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System.out.println("Iterating Using KeySet and For Each");
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mapIteration.iterateUsingKeySetAndForeach(map);
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System.out.println("Iterating Map Using Lambda Expression");
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mapIteration.iterateUsingLambda(map);
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System.out.println("Iterating Using Stream API");
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mapIteration.iterateUsingStreamAPI(map);
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}
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public void iterateUsingEntrySet(Map<String, Integer> map) {
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for (Map.Entry<String, Integer> entry : map.entrySet()) {
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System.out.println(entry.getKey() + ":" + entry.getValue());
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}
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}
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public void iterateUsingLambda(Map<String, Integer> map) {
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map.forEach((k, v) -> System.out.println((k + ":" + v)));
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}
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public void iterateUsingIteratorAndEntry(Map<String, Integer> map) {
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Iterator<Map.Entry<String, Integer>> iterator = map.entrySet()
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.iterator();
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while (iterator.hasNext()) {
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Map.Entry<String, Integer> pair = iterator.next();
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System.out.println(pair.getKey() + ":" + pair.getValue());
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}
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}
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public void iterateUsingKeySetAndForeach(Map<String, Integer> map) {
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for (String key : map.keySet()) {
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System.out.println(key + ":" + map.get(key));
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}
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}
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public void iterateUsingStreamAPI(Map<String, Integer> map) {
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map.entrySet()
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.stream()
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.forEach(e -> System.out.println(e.getKey() + ":" + e.getValue()));
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}
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public void iterateKeys(Map<String, Integer> map) {
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for (String key : map.keySet()) {
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System.out.println(key);
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}
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}
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}
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@@ -0,0 +1,105 @@
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package com.baeldung.map.java_8;
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import com.baeldung.sort.Employee;
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import one.util.streamex.EntryStream;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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public class MergeMaps {
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private static Map<String, Employee> map1 = new HashMap<>();
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private static Map<String, Employee> map2 = new HashMap<>();
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public static void main(String[] args) {
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initialize();
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mergeFunction();
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streamConcat();
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streamOf();
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streamEx();
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streamMerge();
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}
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private static void streamMerge() {
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Map<String, Employee> map3 = map2.entrySet()
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.stream()
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.collect(
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Collectors.toMap(
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Map.Entry::getKey,
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Map.Entry::getValue,
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(v1, v2) -> new Employee(v1.getId(), v2.getName()),
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() -> new HashMap<>(map1)
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)
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);
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System.out.println(map3);
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}
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private static void streamEx() {
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Map<String, Employee> map3 = EntryStream.of(map1)
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.append(EntryStream.of(map2))
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.toMap((e1, e2) -> e1);
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System.out.println(map3);
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}
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private static void streamOf() {
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Map<String, Employee> map3 = Stream.of(map1, map2)
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.flatMap(map -> map.entrySet().stream())
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.collect(
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Collectors.toMap(
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Map.Entry::getKey,
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Map.Entry::getValue,
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(v1, v2) -> new Employee(v1.getId(), v2.getName())
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)
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);
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map3.entrySet().forEach(System.out::println);
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}
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private static void streamConcat() {
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Map<String, Employee> result = Stream.concat(map1.entrySet().stream(), map2.entrySet().stream()).collect(Collectors.toMap(
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Map.Entry::getKey,
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Map.Entry::getValue,
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(value1, value2) -> new Employee(value2.getId(), value1.getName())
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));
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result.entrySet().forEach(System.out::println);
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}
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private static void mergeFunction() {
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Map<String, Employee> map3 = new HashMap<>(map1);
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map2.forEach(
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(key, value) -> map3.merge(key, value, (v1, v2) ->
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new Employee(v1.getId(), v2.getName()))
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);
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map3.entrySet().forEach(System.out::println);
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}
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private static void initialize() {
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Employee employee1 = new Employee(1L, "Henry");
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map1.put(employee1.getName(), employee1);
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Employee employee2 = new Employee(22L, "Annie");
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map1.put(employee2.getName(), employee2);
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Employee employee3 = new Employee(8L, "John");
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map1.put(employee3.getName(), employee3);
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Employee employee4 = new Employee(2L, "George");
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map2.put(employee4.getName(), employee4);
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Employee employee5 = new Employee(3L, "Henry");
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map2.put(employee5.getName(), employee5);
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}
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}
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@@ -0,0 +1,96 @@
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package com.baeldung.map.util;
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import java.util.Collections;
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import java.util.Comparator;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.Map.Entry;
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import java.util.Optional;
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public class MapMax {
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public <K, V extends Comparable<V>> V maxUsingIteration(Map<K, V> map) {
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Map.Entry<K, V> maxEntry = null;
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for (Map.Entry<K, V> entry : map.entrySet()) {
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if (maxEntry == null || entry.getValue()
|
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.compareTo(maxEntry.getValue()) > 0) {
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maxEntry = entry;
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}
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}
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return maxEntry.getValue();
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}
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public <K, V extends Comparable<V>> V maxUsingCollectionsMax(Map<K, V> map) {
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Entry<K, V> maxEntry = Collections.max(map.entrySet(), new Comparator<Entry<K, V>>() {
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public int compare(Entry<K, V> e1, Entry<K, V> e2) {
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return e1.getValue()
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.compareTo(e2.getValue());
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}
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});
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return maxEntry.getValue();
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}
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public <K, V extends Comparable<V>> V maxUsingCollectionsMaxAndLambda(Map<K, V> map) {
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Entry<K, V> maxEntry = Collections.max(map.entrySet(), (Entry<K, V> e1, Entry<K, V> e2) -> e1.getValue()
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.compareTo(e2.getValue()));
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return maxEntry.getValue();
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}
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public <K, V extends Comparable<V>> V maxUsingCollectionsMaxAndMethodReference(Map<K, V> map) {
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Entry<K, V> maxEntry = Collections.max(map.entrySet(), Comparator.comparing(Map.Entry::getValue));
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|
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return maxEntry.getValue();
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}
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|
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public <K, V extends Comparable<V>> V maxUsingStreamAndLambda(Map<K, V> map) {
|
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|
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Optional<Entry<K, V>> maxEntry = map.entrySet()
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.stream()
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.max((Entry<K, V> e1, Entry<K, V> e2) -> e1.getValue()
|
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.compareTo(e2.getValue()));
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|
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return maxEntry.get()
|
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.getValue();
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}
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public <K, V extends Comparable<V>> V maxUsingStreamAndMethodReference(Map<K, V> map) {
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|
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Optional<Entry<K, V>> maxEntry = map.entrySet()
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.stream()
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.max(Comparator.comparing(Map.Entry::getValue));
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return maxEntry.get()
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.getValue();
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}
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public static void main(String[] args) {
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Map<Integer, Integer> map = new HashMap<Integer, Integer>();
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map.put(1, 3);
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map.put(2, 4);
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map.put(3, 5);
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map.put(4, 6);
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map.put(5, 7);
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|
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MapMax mapMax = new MapMax();
|
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System.out.println(mapMax.maxUsingIteration(map));
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System.out.println(mapMax.maxUsingCollectionsMax(map));
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System.out.println(mapMax.maxUsingCollectionsMaxAndLambda(map));
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System.out.println(mapMax.maxUsingCollectionsMaxAndMethodReference(map));
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System.out.println(mapMax.maxUsingStreamAndLambda(map));
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System.out.println(mapMax.maxUsingStreamAndMethodReference(map));
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|
||||
}
|
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|
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}
|
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@@ -0,0 +1,60 @@
|
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package com.baeldung.sort;
|
||||
|
||||
public class Employee implements Comparable<Employee> {
|
||||
|
||||
private Long id;
|
||||
private String name;
|
||||
|
||||
public Employee(Long id, String name) {
|
||||
this.name = name;
|
||||
this.id = id;
|
||||
}
|
||||
|
||||
public Long getId() {
|
||||
return id;
|
||||
}
|
||||
|
||||
public void setId(Long id) {
|
||||
this.id = id;
|
||||
}
|
||||
|
||||
public String getName() {
|
||||
return name;
|
||||
}
|
||||
|
||||
public void setName(String name) {
|
||||
this.name = name;
|
||||
}
|
||||
|
||||
@Override
|
||||
public boolean equals(Object o) {
|
||||
if (this == o) return true;
|
||||
if (o == null || getClass() != o.getClass()) return false;
|
||||
|
||||
Employee employee = (Employee) o;
|
||||
|
||||
if (!id.equals(employee.id)) return false;
|
||||
return name.equals(employee.name);
|
||||
|
||||
}
|
||||
|
||||
@Override
|
||||
public int hashCode() {
|
||||
int result = id.hashCode();
|
||||
result = 31 * result + name.hashCode();
|
||||
return result;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "Employee{" +
|
||||
"id=" + id +
|
||||
", name='" + name + '\'' +
|
||||
'}';
|
||||
}
|
||||
|
||||
@Override
|
||||
public int compareTo(Employee employee) {
|
||||
return (int)(this.id - employee.getId());
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,104 @@
|
||||
package com.baeldung.sort;
|
||||
|
||||
import com.google.common.base.Functions;
|
||||
import com.google.common.collect.ImmutableSortedMap;
|
||||
import com.google.common.collect.Lists;
|
||||
import com.google.common.collect.Ordering;
|
||||
|
||||
import java.util.*;
|
||||
import java.util.stream.Collectors;
|
||||
|
||||
public class SortHashMap {
|
||||
|
||||
private static Map<String, Employee> map = new HashMap<>();
|
||||
|
||||
public static void main(String[] args) {
|
||||
|
||||
initialize();
|
||||
|
||||
treeMapSortByKey();
|
||||
|
||||
arrayListSortByValue();
|
||||
arrayListSortByKey();
|
||||
|
||||
sortStream();
|
||||
|
||||
sortGuava();
|
||||
|
||||
addDuplicates();
|
||||
|
||||
treeSetByKey();
|
||||
treeSetByValue();
|
||||
|
||||
}
|
||||
|
||||
private static void sortGuava() {
|
||||
final Ordering naturalOrdering =
|
||||
Ordering.natural().onResultOf(Functions.forMap(map, null));
|
||||
|
||||
System.out.println(ImmutableSortedMap.copyOf(map, naturalOrdering));
|
||||
}
|
||||
|
||||
private static void sortStream() {
|
||||
map.entrySet().stream()
|
||||
.sorted(Map.Entry.<String, Employee>comparingByKey().reversed())
|
||||
.forEach(System.out::println);
|
||||
|
||||
Map<String, Employee> result = map.entrySet().stream()
|
||||
.sorted(Map.Entry.comparingByValue())
|
||||
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
|
||||
(oldValue, newValue) -> oldValue, LinkedHashMap::new));
|
||||
|
||||
result.entrySet().forEach(System.out::println);
|
||||
}
|
||||
|
||||
private static void treeSetByValue() {
|
||||
SortedSet<Employee> values = new TreeSet<>(map.values());
|
||||
System.out.println(values);
|
||||
}
|
||||
|
||||
private static void treeSetByKey() {
|
||||
SortedSet<String> keysSet = new TreeSet<>(map.keySet());
|
||||
System.out.println(keysSet);
|
||||
}
|
||||
|
||||
private static void treeMapSortByKey() {
|
||||
TreeMap<String, Employee> sorted = new TreeMap<>(map);
|
||||
sorted.putAll(map);
|
||||
|
||||
sorted.entrySet().forEach(System.out::println);
|
||||
|
||||
}
|
||||
|
||||
private static void arrayListSortByValue() {
|
||||
List<Employee> employeeById = new ArrayList<>(map.values());
|
||||
|
||||
Collections.sort(employeeById);
|
||||
|
||||
System.out.println(employeeById);
|
||||
}
|
||||
|
||||
private static void arrayListSortByKey() {
|
||||
List<String> employeeByKey = new ArrayList<>(map.keySet());
|
||||
Collections.sort(employeeByKey);
|
||||
System.out.println(employeeByKey);
|
||||
}
|
||||
|
||||
private static void initialize() {
|
||||
Employee employee1 = new Employee(1L, "Mher");
|
||||
map.put(employee1.getName(), employee1);
|
||||
Employee employee2 = new Employee(22L, "Annie");
|
||||
map.put(employee2.getName(), employee2);
|
||||
Employee employee3 = new Employee(8L, "John");
|
||||
map.put(employee3.getName(), employee3);
|
||||
Employee employee4 = new Employee(2L, "George");
|
||||
map.put(employee4.getName(), employee4);
|
||||
}
|
||||
|
||||
private static void addDuplicates() {
|
||||
Employee employee5 = new Employee(1L, "Mher");
|
||||
map.put(employee5.getName(), employee5);
|
||||
Employee employee6 = new Employee(22L, "Annie");
|
||||
map.put(employee6.getName(), employee6);
|
||||
}
|
||||
}
|
||||
13
java-collections-maps/src/main/resources/logback.xml
Normal file
13
java-collections-maps/src/main/resources/logback.xml
Normal file
@@ -0,0 +1,13 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<configuration>
|
||||
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
|
||||
<encoder>
|
||||
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
|
||||
</pattern>
|
||||
</encoder>
|
||||
</appender>
|
||||
|
||||
<root level="INFO">
|
||||
<appender-ref ref="STDOUT" />
|
||||
</root>
|
||||
</configuration>
|
||||
@@ -0,0 +1,60 @@
|
||||
package com.baeldung.collection;
|
||||
|
||||
import java.util.ConcurrentModificationException;
|
||||
import java.util.HashMap;
|
||||
import java.util.Iterator;
|
||||
import java.util.Map;
|
||||
import java.util.TreeMap;
|
||||
|
||||
import org.hamcrest.Matchers;
|
||||
import org.junit.Assert;
|
||||
import org.junit.Test;
|
||||
|
||||
public class WhenComparingTreeMapVsHashMap {
|
||||
|
||||
@Test
|
||||
public void whenInsertObjectsTreeMap_thenNaturalOrder() {
|
||||
Map<Integer, String> treemap = new TreeMap<>();
|
||||
treemap.put(3, "TreeMap");
|
||||
treemap.put(2, "vs");
|
||||
treemap.put(1, "HashMap");
|
||||
Assert.assertThat(treemap.keySet(), Matchers.contains(1, 2, 3));
|
||||
}
|
||||
|
||||
@Test(expected = NullPointerException.class)
|
||||
public void whenInsertNullInTreeMap_thenException() {
|
||||
Map<Integer, String> treemap = new TreeMap<>();
|
||||
treemap.put(null, "NullPointerException");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenInsertObjectsHashMap_thenRandomOrder() {
|
||||
Map<Integer, String> hashmap = new HashMap<>();
|
||||
hashmap.put(3, "TreeMap");
|
||||
hashmap.put(2, "vs");
|
||||
hashmap.put(1, "HashMap");
|
||||
Assert.assertThat(hashmap.keySet(), Matchers.containsInAnyOrder(1, 2, 3));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenInsertNullInHashMap_thenInsertsNull() {
|
||||
Map<Integer, String> hashmap = new HashMap<>();
|
||||
hashmap.put(null, null);
|
||||
Assert.assertNull(hashmap.get(null));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashMapAndTreeMap_whenputDuplicates_thenOnlyUnique() {
|
||||
Map<Integer, String> treeMap = new HashMap<>();
|
||||
treeMap.put(1, "Baeldung");
|
||||
treeMap.put(1, "Baeldung");
|
||||
|
||||
Assert.assertTrue(treeMap.size() == 1);
|
||||
|
||||
Map<Integer, String> treeMap2 = new TreeMap<>();
|
||||
treeMap2.put(1, "Baeldung");
|
||||
treeMap2.put(1, "Baeldung");
|
||||
|
||||
Assert.assertTrue(treeMap2.size() == 1);
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,29 @@
|
||||
package com.baeldung.java.map;
|
||||
|
||||
import static org.junit.Assert.assertFalse;
|
||||
import static org.junit.Assert.assertNull;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
|
||||
import java.util.Collections;
|
||||
import java.util.Map;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
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);
|
||||
|
||||
assertTrue(map.containsKey("nothing"));
|
||||
assertNull(map.get("nothing"));
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,124 @@
|
||||
package com.baeldung.java.map;
|
||||
|
||||
import static org.assertj.core.api.Assertions.assertThat;
|
||||
|
||||
import java.util.ArrayList;
|
||||
import java.util.Collection;
|
||||
import java.util.HashMap;
|
||||
import java.util.List;
|
||||
import java.util.Map;
|
||||
|
||||
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 com.google.common.collect.ArrayListMultimap;
|
||||
import com.google.common.collect.LinkedHashMultimap;
|
||||
import com.google.common.collect.Multimap;
|
||||
import com.google.common.collect.TreeMultimap;
|
||||
|
||||
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");
|
||||
}
|
||||
|
||||
}
|
||||
@@ -0,0 +1,336 @@
|
||||
package com.baeldung.java.map;
|
||||
|
||||
import org.junit.Test;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
import java.util.*;
|
||||
import java.util.Map.Entry;
|
||||
|
||||
import static org.junit.Assert.*;
|
||||
|
||||
public class MapUnitTest {
|
||||
private static final Logger LOG = LoggerFactory.getLogger(MapUnitTest.class);
|
||||
|
||||
|
||||
@Test
|
||||
public void givenHashMap_whenRetrievesKeyset_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("name", "baeldung");
|
||||
map.put("type", "blog");
|
||||
|
||||
Set<String> keys = map.keySet();
|
||||
|
||||
assertEquals(2, keys.size());
|
||||
assertTrue(keys.contains("name"));
|
||||
assertTrue(keys.contains("type"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashMap_whenRetrievesValues_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("name", "baeldung");
|
||||
map.put("type", "blog");
|
||||
|
||||
Collection<String> values = map.values();
|
||||
|
||||
assertEquals(2, values.size());
|
||||
assertTrue(values.contains("baeldung"));
|
||||
assertTrue(values.contains("blog"));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashMap_whenRetrievesEntries_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("name", "baeldung");
|
||||
map.put("type", "blog");
|
||||
|
||||
Set<Entry<String, String>> entries = map.entrySet();
|
||||
|
||||
assertEquals(2, entries.size());
|
||||
for (Entry<String, String> e : entries) {
|
||||
String key = e.getKey();
|
||||
String val = e.getValue();
|
||||
assertTrue(key.equals("name") || key.equals("type"));
|
||||
assertTrue(val.equals("baeldung") || val.equals("blog"));
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenKeySet_whenChangeReflectsInMap_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("name", "baeldung");
|
||||
map.put("type", "blog");
|
||||
|
||||
assertEquals(2, map.size());
|
||||
|
||||
Set<String> keys = map.keySet();
|
||||
|
||||
keys.remove("name");
|
||||
assertEquals(1, map.size());
|
||||
}
|
||||
|
||||
@Test(expected = ConcurrentModificationException.class)
|
||||
public void givenIterator_whenFailsFastOnModification_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("name", "baeldung");
|
||||
map.put("type", "blog");
|
||||
|
||||
Set<String> keys = map.keySet();
|
||||
Iterator<String> it = keys.iterator();
|
||||
map.remove("type");
|
||||
while (it.hasNext()) {
|
||||
String key = it.next();
|
||||
}
|
||||
}
|
||||
|
||||
public void givenIterator_whenRemoveWorks_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("name", "baeldung");
|
||||
map.put("type", "blog");
|
||||
|
||||
Set<String> keys = map.keySet();
|
||||
Iterator<String> it = keys.iterator();
|
||||
while (it.hasNext()) {
|
||||
it.next();
|
||||
it.remove();
|
||||
}
|
||||
assertEquals(0, map.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenHashCodeIsCalledOnPut_thenCorrect() {
|
||||
MyKey key = new MyKey(1, "name");
|
||||
Map<MyKey, String> map = new HashMap<>();
|
||||
map.put(key, "val");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenHashCodeIsCalledOnGet_thenCorrect() {
|
||||
MyKey key = new MyKey(1, "name");
|
||||
Map<MyKey, String> map = new HashMap<>();
|
||||
map.put(key, "val");
|
||||
map.get(key);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenGetWorks_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("key", "val");
|
||||
|
||||
String val = map.get("key");
|
||||
|
||||
assertEquals("val", val);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenNewKey_whenPutReturnsNull_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
|
||||
String rtnVal = map.put("key1", "val1");
|
||||
|
||||
assertNull(rtnVal);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenUnmappedKey_whenGetReturnsNull_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
|
||||
String rtnVal = map.get("key1");
|
||||
|
||||
assertNull(rtnVal);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenNullVal_whenPutReturnsNull_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
|
||||
String rtnVal = map.put("key1", null);
|
||||
|
||||
assertNull(rtnVal);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenNullKeyAndVal_whenAccepts_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
|
||||
map.put(null, null);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenNullVal_whenRetrieves_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("key", null);
|
||||
|
||||
String val = map.get("key");
|
||||
|
||||
assertNull(val);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenContainsDistinguishesNullValues_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
|
||||
String val1 = map.get("key");
|
||||
boolean valPresent = map.containsKey("key");
|
||||
|
||||
assertNull(val1);
|
||||
assertFalse(valPresent);
|
||||
|
||||
map.put("key", null);
|
||||
String val = map.get("key");
|
||||
valPresent = map.containsKey("key");
|
||||
|
||||
assertNull(val);
|
||||
assertTrue(valPresent);
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenPutReturnsPrevValue_thenCorrect() {
|
||||
Map<String, String> map = new HashMap<>();
|
||||
map.put("key1", "val1");
|
||||
String rtnVal = map.put("key1", "val2");
|
||||
|
||||
assertEquals("val1", rtnVal);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenCallsEqualsOnCollision_thenCorrect() {
|
||||
HashMap<MyKey, String> map = new HashMap<>();
|
||||
MyKey k1 = new MyKey(1, "firstKey");
|
||||
MyKey k2 = new MyKey(2, "secondKey");
|
||||
MyKey k3 = new MyKey(2, "thirdKey");
|
||||
|
||||
LOG.debug("storing value for k1");
|
||||
map.put(k1, "firstValue");
|
||||
|
||||
LOG.debug("storing value for k2");
|
||||
map.put(k2, "secondValue");
|
||||
|
||||
LOG.debug("storing value for k3");
|
||||
map.put(k3, "thirdValue");
|
||||
|
||||
LOG.debug("retrieving value for k1");
|
||||
String v1 = map.get(k1);
|
||||
|
||||
LOG.debug("retrieving value for k2");
|
||||
String v2 = map.get(k2);
|
||||
|
||||
LOG.debug("retrieving value for k3");
|
||||
String v3 = map.get(k3);
|
||||
|
||||
assertEquals("firstValue", v1);
|
||||
assertEquals("secondValue", v2);
|
||||
assertEquals("thirdValue", v3);
|
||||
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenLinkedHashMap_whenGetsOrderedKeyset_thenCorrect() {
|
||||
LinkedHashMap<Integer, String> map = new LinkedHashMap<>();
|
||||
map.put(1, null);
|
||||
map.put(2, null);
|
||||
map.put(3, null);
|
||||
map.put(4, null);
|
||||
map.put(5, null);
|
||||
Set<Integer> keys = map.keySet();
|
||||
Integer[] arr = keys.toArray(new Integer[0]);
|
||||
for (int i = 0; i < arr.length; i++) {
|
||||
assertEquals(new Integer(i + 1), arr[i]);
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenLinkedHashMap_whenAccessOrderWorks_thenCorrect() {
|
||||
LinkedHashMap<Integer, String> map = new LinkedHashMap<>(16, .75f, true);
|
||||
map.put(1, null);
|
||||
map.put(2, null);
|
||||
map.put(3, null);
|
||||
map.put(4, null);
|
||||
map.put(5, null);
|
||||
Set<Integer> keys = map.keySet();
|
||||
assertEquals("[1, 2, 3, 4, 5]", keys.toString());
|
||||
map.get(4);
|
||||
assertEquals("[1, 2, 3, 5, 4]", keys.toString());
|
||||
map.get(1);
|
||||
assertEquals("[2, 3, 5, 4, 1]", keys.toString());
|
||||
map.get(3);
|
||||
assertEquals("[2, 5, 4, 1, 3]", keys.toString());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenLinkedHashMap_whenRemovesEldestEntry_thenCorrect() {
|
||||
LinkedHashMap<Integer, String> map = new MyLinkedHashMap<>(16, .75f, true);
|
||||
map.put(1, null);
|
||||
map.put(2, null);
|
||||
map.put(3, null);
|
||||
map.put(4, null);
|
||||
map.put(5, null);
|
||||
Set<Integer> keys = map.keySet();
|
||||
assertEquals("[1, 2, 3, 4, 5]", keys.toString());
|
||||
map.put(6, null);
|
||||
assertEquals("[2, 3, 4, 5, 6]", keys.toString());
|
||||
map.put(7, null);
|
||||
assertEquals("[3, 4, 5, 6, 7]", keys.toString());
|
||||
map.put(8, null);
|
||||
assertEquals("[4, 5, 6, 7, 8]", keys.toString());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenTreeMap_whenOrdersEntriesNaturally_thenCorrect() {
|
||||
TreeMap<Integer, String> map = new TreeMap<>();
|
||||
map.put(3, "val");
|
||||
map.put(2, "val");
|
||||
map.put(1, "val");
|
||||
map.put(5, "val");
|
||||
map.put(4, "val");
|
||||
assertEquals("[1, 2, 3, 4, 5]", map.keySet().toString());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenTreeMap_whenOrdersEntriesNaturally_thenCorrect2() {
|
||||
TreeMap<String, String> map = new TreeMap<>();
|
||||
map.put("c", "val");
|
||||
map.put("b", "val");
|
||||
map.put("a", "val");
|
||||
map.put("e", "val");
|
||||
map.put("d", "val");
|
||||
|
||||
assertEquals("[a, b, c, d, e]", map.keySet().toString());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenTreeMap_whenOrdersEntriesByComparator_thenCorrect() {
|
||||
TreeMap<Integer, String> map = new TreeMap<>(Comparator.reverseOrder());
|
||||
map.put(3, "val");
|
||||
map.put(2, "val");
|
||||
map.put(1, "val");
|
||||
map.put(5, "val");
|
||||
map.put(4, "val");
|
||||
|
||||
assertEquals("[5, 4, 3, 2, 1]", map.keySet().toString());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenTreeMap_whenPerformsQueries_thenCorrect() {
|
||||
TreeMap<Integer, String> map = new TreeMap<>();
|
||||
map.put(3, "val");
|
||||
map.put(2, "val");
|
||||
map.put(1, "val");
|
||||
map.put(5, "val");
|
||||
map.put(4, "val");
|
||||
|
||||
Integer highestKey = map.lastKey();
|
||||
Integer lowestKey = map.firstKey();
|
||||
Set<Integer> keysLessThan3 = map.headMap(3).keySet();
|
||||
Set<Integer> keysGreaterThanEqTo3 = map.tailMap(3).keySet();
|
||||
|
||||
assertEquals(new Integer(5), highestKey);
|
||||
assertEquals(new Integer(1), lowestKey);
|
||||
assertEquals("[1, 2]", keysLessThan3.toString());
|
||||
assertEquals("[3, 4, 5]", keysGreaterThanEqTo3.toString());
|
||||
}
|
||||
|
||||
}
|
||||
@@ -0,0 +1,104 @@
|
||||
/**
|
||||
*
|
||||
*/
|
||||
package com.baeldung.java.map;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
|
||||
import java.util.Arrays;
|
||||
import java.util.HashMap;
|
||||
import java.util.HashSet;
|
||||
import java.util.Map;
|
||||
import java.util.stream.Collectors;
|
||||
|
||||
import org.apache.commons.collections4.BidiMap;
|
||||
import org.apache.commons.collections4.bidimap.DualHashBidiMap;
|
||||
import org.junit.Test;
|
||||
|
||||
import com.google.common.collect.HashBiMap;
|
||||
|
||||
/**
|
||||
* @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"));
|
||||
}
|
||||
|
||||
}
|
||||
@@ -0,0 +1,27 @@
|
||||
package com.baeldung.java.map.initialize;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
|
||||
import java.util.Map;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
public class MapInitializerUnitTest {
|
||||
|
||||
@Test
|
||||
public void givenStaticMap_whenUpdated_thenCorrect() {
|
||||
|
||||
MapInitializer.articleMapOne.put("NewArticle1", "Convert array to List");
|
||||
|
||||
assertEquals(MapInitializer.articleMapOne.get("NewArticle1"), "Convert array to List");
|
||||
|
||||
}
|
||||
|
||||
@Test(expected=UnsupportedOperationException.class)
|
||||
public void givenSingleTonMap_whenEntriesAdded_throwsException() {
|
||||
|
||||
Map<String, String> map = MapInitializer.createSingletonMap();
|
||||
map.put("username2", "password2");
|
||||
}
|
||||
|
||||
}
|
||||
@@ -0,0 +1,59 @@
|
||||
package com.baeldung.map.util;
|
||||
|
||||
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
|
||||
import java.util.HashMap;
|
||||
import java.util.Map;
|
||||
|
||||
import org.junit.Before;
|
||||
import org.junit.Test;
|
||||
|
||||
public class MapMaxUnitTest {
|
||||
|
||||
Map<Integer, Integer> map = null;
|
||||
MapMax mapMax = null;
|
||||
|
||||
|
||||
@Before
|
||||
public void setupTestData() {
|
||||
map = new HashMap<Integer, Integer>();
|
||||
map.put(23, 12);
|
||||
map.put(46, 24);
|
||||
map.put(27, 38);
|
||||
mapMax = new MapMax();
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMap_whenIterated_thenReturnMaxValue() {
|
||||
assertEquals(new Integer(38), mapMax.maxUsingIteration(map));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMap_whenUsingCollectionsMax_thenReturnMaxValue() {
|
||||
assertEquals(new Integer(38), mapMax.maxUsingCollectionsMax(map));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMap_whenUsingCollectionsMaxAndLambda_thenReturnMaxValue() {
|
||||
assertEquals(new Integer(38), mapMax.maxUsingCollectionsMaxAndLambda(map));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMap_whenUsingCollectionsMaxAndMethodReference_thenReturnMaxValue() {
|
||||
assertEquals(new Integer(38), mapMax.maxUsingCollectionsMaxAndMethodReference(map));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMap_whenUsingStreamAndLambda_thenReturnMaxValue() {
|
||||
assertEquals(new Integer(38), mapMax.maxUsingStreamAndLambda(map));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenMap_whenUsingStreamAndMethodReference_thenReturnMaxValue() {
|
||||
assertEquals(new Integer(38), mapMax.maxUsingStreamAndMethodReference (map));
|
||||
}
|
||||
|
||||
|
||||
}
|
||||
@@ -0,0 +1,72 @@
|
||||
package com.baeldung.weakhashmap;
|
||||
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
import java.util.WeakHashMap;
|
||||
import java.util.concurrent.TimeUnit;
|
||||
|
||||
import static com.jayway.awaitility.Awaitility.await;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
|
||||
public class WeakHashMapUnitTest {
|
||||
|
||||
@Test
|
||||
public void givenWeakHashMap_whenCacheValueThatHasNoReferenceToIt_GCShouldReclaimThatObject() {
|
||||
//given
|
||||
WeakHashMap<UniqueImageName, BigImage> map = new WeakHashMap<>();
|
||||
BigImage bigImage = new BigImage("image_id");
|
||||
UniqueImageName imageName = new UniqueImageName("name_of_big_image");
|
||||
|
||||
map.put(imageName, bigImage);
|
||||
assertTrue(map.containsKey(imageName));
|
||||
|
||||
//when big image key is not reference anywhere
|
||||
imageName = null;
|
||||
System.gc();
|
||||
|
||||
//then GC will finally reclaim that object
|
||||
await().atMost(10, TimeUnit.SECONDS).until(map::isEmpty);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenWeakHashMap_whenCacheValueThatHasNoReferenceToIt_GCShouldReclaimThatObjectButLeaveReferencedObject() {
|
||||
//given
|
||||
WeakHashMap<UniqueImageName, BigImage> map = new WeakHashMap<>();
|
||||
BigImage bigImageFirst = new BigImage("foo");
|
||||
UniqueImageName imageNameFirst = new UniqueImageName("name_of_big_image");
|
||||
|
||||
BigImage bigImageSecond = new BigImage("foo_2");
|
||||
UniqueImageName imageNameSecond = new UniqueImageName("name_of_big_image_2");
|
||||
|
||||
map.put(imageNameFirst, bigImageFirst);
|
||||
map.put(imageNameSecond, bigImageSecond);
|
||||
assertTrue(map.containsKey(imageNameFirst));
|
||||
assertTrue(map.containsKey(imageNameSecond));
|
||||
|
||||
//when
|
||||
imageNameFirst = null;
|
||||
System.gc();
|
||||
|
||||
//then
|
||||
await().atMost(10, TimeUnit.SECONDS).until(() -> map.size() == 1);
|
||||
await().atMost(10, TimeUnit.SECONDS).until(() -> map.containsKey(imageNameSecond));
|
||||
}
|
||||
|
||||
|
||||
class BigImage {
|
||||
public final String imageId;
|
||||
|
||||
BigImage(String imageId) {
|
||||
this.imageId = imageId;
|
||||
}
|
||||
}
|
||||
|
||||
class UniqueImageName {
|
||||
public final String imageName;
|
||||
|
||||
UniqueImageName(String imageName) {
|
||||
this.imageName = imageName;
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user