Merge pull request #8125 from eugenp/revert-8119-BAEL-3275-2

Revert "BAEL-3275: Using blocking queue for pub-sub"

java-collections-maps-2/src/test/java/com/baeldung/map/ProductUnitTest.java

@@ -0,0 +1,124 @@
+package com.baeldung.map;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ProductUnitTest {
+
+
+    @Test
+    public void getExistingValue() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product eBike = new Product("E-Bike", "A bike with a battery");
+        Product roadBike = new Product("Road bike", "A bike for competition");
+
+        productsByName.put(eBike.getName(), eBike);
+        productsByName.put(roadBike.getName(), roadBike);
+
+        Product nextPurchase = productsByName.get("E-Bike");
+
+        assertEquals("A bike with a battery", nextPurchase.getDescription());
+    }
+
+    @Test
+    public void getNonExistingValue() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product eBike = new Product("E-Bike", "A bike with a battery");
+        Product roadBike = new Product("Road bike", "A bike for competition");
+
+        productsByName.put(eBike.getName(), eBike);
+        productsByName.put(roadBike.getName(), roadBike);
+
+        Product nextPurchase = productsByName.get("Car");
+
+        assertNull(nextPurchase);
+    }
+
+    @Test
+    public void getExistingValueAfterSameKeyInsertedTwice() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product eBike = new Product("E-Bike", "A bike with a battery");
+        Product roadBike = new Product("Road bike", "A bike for competition");
+        Product newEBike = new Product("E-Bike", "A bike with a better battery");
+
+        productsByName.put(eBike.getName(), eBike);
+        productsByName.put(roadBike.getName(), roadBike);
+        productsByName.put(newEBike.getName(), newEBike);
+
+        Product nextPurchase = productsByName.get("E-Bike");
+
+        assertEquals("A bike with a better battery", nextPurchase.getDescription());
+    }
+
+    @Test
+    public void getExistingValueWithNullKey() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product defaultProduct = new Product("Chocolate", "At least buy chocolate");
+
+        productsByName.put(null, defaultProduct);
+        productsByName.put(defaultProduct.getName(), defaultProduct);
+
+        Product nextPurchase = productsByName.get(null);
+        assertEquals("At least buy chocolate", nextPurchase.getDescription());
+
+        nextPurchase = productsByName.get("Chocolate");
+        assertEquals("At least buy chocolate", nextPurchase.getDescription());
+    }
+
+    @Test
+    public void insertSameObjectWithDifferentKey() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product defaultProduct = new Product("Chocolate", "At least buy chocolate");
+
+        productsByName.put(null, defaultProduct);
+        productsByName.put(defaultProduct.getName(), defaultProduct);
+
+        assertSame(productsByName.get(null), productsByName.get("Chocolate"));
+    }
+
+    @Test
+    public void checkIfKeyExists() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product eBike = new Product("E-Bike", "A bike with a battery");
+
+        productsByName.put(eBike.getName(), eBike);
+
+        assertTrue(productsByName.containsKey("E-Bike"));
+    }
+
+    @Test
+    public void checkIfValueExists() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product eBike = new Product("E-Bike", "A bike with a battery");
+
+        productsByName.put(eBike.getName(), eBike);
+
+        assertTrue(productsByName.containsValue(eBike));
+    }
+
+    @Test
+    public void removeExistingKey() {
+        HashMap<String, Product> productsByName = new HashMap<>();
+
+        Product eBike = new Product("E-Bike", "A bike with a battery");
+        Product roadBike = new Product("Road bike", "A bike for competition");
+
+        productsByName.put(eBike.getName(), eBike);
+        productsByName.put(roadBike.getName(), roadBike);
+
+        productsByName.remove("E-Bike");
+
+        assertNull(productsByName.get("E-Bike"));
+    }
+
+}

java-collections-maps-2/src/test/java/com/baeldung/map/convert/MapToStringUnitTest.java

@@ -0,0 +1,48 @@
+package com.baeldung.map.convert;
+
+import org.apache.commons.collections4.MapUtils;
+import org.junit.Assert;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class MapToStringUnitTest {
+
+    private Map<Integer, String> wordsByKey = new HashMap<>();
+
+    @BeforeEach
+    public void setup() {
+        wordsByKey.clear();
+        wordsByKey.put(1, "one");
+        wordsByKey.put(2, "two");
+        wordsByKey.put(3, "three");
+        wordsByKey.put(4, "four");
+    }
+
+    @Test
+    public void givenMap_WhenUsingIteration_ThenResultingMapIsCorrect() {
+        String mapAsString = MapToString.convertWithIteration(wordsByKey);
+        Assert.assertEquals("{1=one, 2=two, 3=three, 4=four}", mapAsString);
+    }
+
+    @Test
+    public void givenMap_WhenUsingStream_ThenResultingMapIsCorrect() {
+        String mapAsString = MapToString.convertWithStream(wordsByKey);
+        Assert.assertEquals("{1=one, 2=two, 3=three, 4=four}", mapAsString);
+    }
+
+    @Test
+    public void givenMap_WhenUsingGuava_ThenResultingMapIsCorrect() {
+        String mapAsString = MapToString.convertWithGuava(wordsByKey);
+        Assert.assertEquals("1=one,2=two,3=three,4=four", mapAsString);
+    }
+
+    @Test
+    public void givenMap_WhenUsingApache_ThenResultingMapIsCorrect() {
+        String mapAsString = MapToString.convertWithApache(wordsByKey);
+        Assert.assertEquals("{1=one, 2=two, 3=three, 4=four}", mapAsString);
+        MapUtils.debugPrint(System.out, "Map as String", wordsByKey);
+    }
+}

java-collections-maps-2/src/test/java/com/baeldung/map/convert/StringToMapUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.map.convert;
+
+import org.junit.Assert;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+
+public class StringToMapUnitTest {
+
+    @Test
+    public void givenString_WhenUsingStream_ThenResultingStringIsCorrect() {
+        Map<String, String> wordsByKey = StringToMap.convertWithStream("1=one,2=two,3=three,4=four");
+        Assert.assertEquals(4, wordsByKey.size());
+        Assert.assertEquals("one", wordsByKey.get("1"));
+    }
+
+    @Test
+    void givenString_WhenUsingGuava_ThenResultingStringIsCorrect() {
+        Map<String, String> wordsByKey = StringToMap.convertWithGuava("1=one,2=two,3=three,4=four");
+        Assert.assertEquals(4, wordsByKey.size());
+        Assert.assertEquals("one", wordsByKey.get("1"));
+    }
+}

java-collections-maps-2/src/test/java/com/baeldung/map/copyhashmap/CopyHashMapUnitTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.map.copyhashmap;
+
+import com.google.common.collect.ImmutableMap;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CopyHashMapUnitTest {
+    
+    @Test
+    public void givenHashMap_whenShallowCopy_thenCopyisNotSameAsOriginal() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+    
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
+        
+        assertThat(shallowCopy).isNotSameAs(map);
+        
+    }
+    
+    @Test
+    public void givenHashMap_whenShallowCopyModifyingOriginalObject_thenCopyShouldChange() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+        
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
+        
+        emp1.setName("Johny");
+        
+        assertThat(shallowCopy.get("emp1")).isEqualTo(map.get("emp1"));
+        
+    }
+    
+    @Test
+    public void givenHashMap_whenDeepCopyModifyingOriginalObject_thenCopyShouldNotChange() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+        HashMap<String, Employee> deepCopy = CopyHashMap.deepCopy(map);
+        
+        emp1.setName("Johny");
+        
+        assertThat(deepCopy.get("emp1")).isNotEqualTo(map.get("emp1"));
+        
+    }
+    
+    @Test
+    public void givenImmutableMap_whenCopyUsingGuava_thenCopyShouldNotChange() {
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        
+        Map<String, Employee> map = ImmutableMap.<String, Employee> builder()
+            .put("emp1",emp1)
+            .put("emp2",emp2)
+            .build();
+        Map<String, Employee> shallowCopy = ImmutableMap.copyOf(map);
+        
+        assertThat(shallowCopy).isSameAs(map);
+        
+    }
+
+}

java-collections-maps-2/src/test/java/com/baeldung/map/copyhashmap/Employee.java

@@ -0,0 +1,28 @@
+package com.baeldung.map.copyhashmap;
+
+import java.io.Serializable;
+
+public class Employee implements Serializable{
+    
+    private String name;
+    
+    public Employee(String name) {
+        super();
+        this.name = name;
+    }
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    @Override
+    public String toString() {
+        return this.name;
+    }
+ 
+}
+
+

java-collections-maps-2/src/test/java/com/baeldung/map/initialize/MapInitializerUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.map.initialize;
+
+import org.junit.Test;
+
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+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");
+    }
+
+}

java-collections-maps-2/src/test/java/com/baeldung/map/mapmax/MapMaxUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.map.mapmax;
+
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+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));
+    }
+
+
+}

java-collections-maps-2/src/test/java/com/baeldung/map/treemaphashmap/TreeMapVsHashMapUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.map.treemaphashmap;
+
+import org.hamcrest.Matchers;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
+
+public class TreeMapVsHashMapUnitTest {
+
+    @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);
+    }
+}

java-collections-maps-2/src/test/java/com/baeldung/map/weakhashmap/WeakHashMapUnitTest.java

@@ -0,0 +1,72 @@
+package com.baeldung.map.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;
+        }
+    }
+}