Merge branch 'BAEL-3283-latest' into BAEL-3283

java-collections-maps/src/test/java/com/baeldung/map/MapUtilUnitTest.java

@@ -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"));
+    }
+
+}