Split or move java-collections-conversions module

java-collections-conversions/src/test/java/com/baeldung/convertcollectiontoarraylist/CollectionToArrayListUnitTest.java

@@ -14,10 +14,10 @@ import static org.junit.Assert.*;
  *
  * @author chris
  */
-public class FooUnitTest {
+public class CollectionToArrayListUnitTest {
     private static Collection<Foo> srcCollection = new HashSet<>();
 
-    public FooUnitTest() {
+    public CollectionToArrayListUnitTest() {
     }
     
     @BeforeClass

java-collections-conversions/src/test/java/com/baeldung/convertiteratortolist/ConvertIteratorToListServiceUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.convert.iteratortolist;
+package com.baeldung.convertiteratortolist;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.collection.IsCollectionWithSize.hasSize;

java-collections-conversions/src/test/java/com/baeldung/convertlisttomap/ConvertListWithDuplicatedIdToMapServiceUnitTest.java

@@ -11,7 +11,7 @@ import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.hasItem;
 import static org.hamcrest.Matchers.hasSize;
 
-public class ConvertListWithDiplicatedIdToMapServiceUnitTest {
+public class ConvertListWithDuplicatedIdToMapServiceUnitTest {
     List<Animal> duplicatedIdList;
 
     private ConvertListToMapService convertListService = new ConvertListToMapService();

java-collections-conversions/src/test/java/com/baeldung/java/collections/JavaCollectionConversionUnitTest.java

@@ -0,0 +1,187 @@
+package com.baeldung.java.collections;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.commons.collections4.CollectionUtils;
+import org.apache.commons.lang3.ArrayUtils;
+import org.junit.Test;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import com.google.common.primitives.Ints;
+
+@SuppressWarnings("unused")
+public class JavaCollectionConversionUnitTest {
+
+    // List -> array; array -> List
+
+    @Test
+    public final void givenUsingCoreJava_whenArrayConvertedToList_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final List<Integer> targetList = Arrays.asList(sourceArray);
+    }
+
+    @Test
+    public final void givenUsingCoreJava_whenListConvertedToArray_thenCorrect() {
+        final List<Integer> sourceList = Arrays.asList(0, 1, 2, 3, 4, 5);
+        final Integer[] targetArray = sourceList.toArray(new Integer[sourceList.size()]);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenArrayConvertedToList_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final List<Integer> targetList = Lists.newArrayList(sourceArray);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenListConvertedToArray_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final int[] targetArray = Ints.toArray(sourceList);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenArrayConvertedToList_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final List<Integer> targetList = new ArrayList<>(6);
+        CollectionUtils.addAll(targetList, sourceArray);
+    }
+
+    // Set -> array; array -> Set
+
+    @Test
+    public final void givenUsingCoreJavaV1_whenArrayConvertedToSet_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final Set<Integer> targetSet = new HashSet<Integer>(Arrays.asList(sourceArray));
+    }
+
+    @Test
+    public final void givenUsingCoreJavaV2_whenArrayConvertedToSet_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final Set<Integer> targetSet = new HashSet<Integer>();
+        Collections.addAll(targetSet, sourceArray);
+    }
+
+    @Test
+    public final void givenUsingCoreJava_whenSetConvertedToArray_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final Integer[] targetArray = sourceSet.toArray(new Integer[sourceSet.size()]);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenArrayConvertedToSet_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final Set<Integer> targetSet = Sets.newHashSet(sourceArray);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenSetConvertedToArray_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final int[] targetArray = Ints.toArray(sourceSet);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenArrayConvertedToSet_thenCorrect() {
+        final Integer[] sourceArray = { 0, 1, 2, 3, 4, 5 };
+        final Set<Integer> targetSet = new HashSet<>(6);
+        CollectionUtils.addAll(targetSet, sourceArray);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenSetConvertedToArray_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final Integer[] targetArray = sourceSet.toArray(new Integer[sourceSet.size()]);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenSetConvertedToArrayOfPrimitives_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final Integer[] targetArray = sourceSet.toArray(new Integer[sourceSet.size()]);
+        final int[] primitiveTargetArray = ArrayUtils.toPrimitive(targetArray);
+    }
+
+    // Set -> List; List -> Set
+
+    public final void givenUsingCoreJava_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = new ArrayList<>(sourceSet);
+    }
+
+    public final void givenUsingCoreJava_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = new HashSet<>(sourceList);
+    }
+
+    public final void givenUsingGuava_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = Lists.newArrayList(sourceSet);
+    }
+
+    public final void givenUsingGuava_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = Sets.newHashSet(sourceList);
+    }
+
+    public final void givenUsingCommonsCollections_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+
+        final Set<Integer> targetSet = new HashSet<>(6);
+        CollectionUtils.addAll(targetSet, sourceList);
+    }
+
+    public final void givenUsingCommonsCollections_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+
+        final List<Integer> targetList = new ArrayList<>(6);
+        CollectionUtils.addAll(targetList, sourceSet);
+    }
+
+    // Map (values) -> Array, List, Set
+
+    @Test
+    public final void givenUsingCoreJava_whenMapValuesConvertedToArray_thenCorrect() {
+        final Map<Integer, String> sourceMap = createMap();
+
+        final Collection<String> values = sourceMap.values();
+        final String[] targetArray = values.toArray(new String[values.size()]);
+    }
+
+    @Test
+    public final void givenUsingCoreJava_whenMapValuesConvertedToList_thenCorrect() {
+        final Map<Integer, String> sourceMap = createMap();
+
+        final List<String> targetList = new ArrayList<>(sourceMap.values());
+    }
+
+    @Test
+    public final void givenUsingGuava_whenMapValuesConvertedToList_thenCorrect() {
+        final Map<Integer, String> sourceMap = createMap();
+
+        final List<String> targetList = Lists.newArrayList(sourceMap.values());
+    }
+
+    @Test
+    public final void givenUsingCoreJava_whenMapValuesConvertedToSet_thenCorrect() {
+        final Map<Integer, String> sourceMap = createMap();
+
+        final Set<String> targetSet = new HashSet<>(sourceMap.values());
+    }
+
+    // UTIL
+
+    private final Map<Integer, String> createMap() {
+        final Map<Integer, String> sourceMap = new HashMap<>(3);
+        sourceMap.put(0, "zero");
+        sourceMap.put(1, "one");
+        sourceMap.put(2, "two");
+        return sourceMap;
+    }
+
+}

java-collections-conversions/src/test/java/com/baeldung/java/lists/ListToStringUnitTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.java.lists;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Test;
+
+public class ListToStringUnitTest {
+
+    @Test
+    public void whenListToString_thenPrintDefault() {
+        List<Integer> intLIst = Arrays.asList(1, 2, 3);
+        System.out.println(intLIst);
+    }
+
+    @Test
+    public void whenCollectorsJoining_thenPrintCustom() {
+        List<Integer> intList = Arrays.asList(1, 2, 3);
+        System.out.println(intList.stream()
+            .map(n -> String.valueOf(n))
+            .collect(Collectors.joining("-", "{", "}")));
+    }
+    
+    @Test
+    public void whenStringUtilsJoin_thenPrintCustom() {
+        List<Integer> intList = Arrays.asList(1, 2, 3);
+       System.out.println(StringUtils.join(intList, "|"));
+    }
+}