example code for BAEL-966 (#2152)

* added updated example codes * updated example code StringToCharStream * deleted StringToCharStream.java locally * removed redundant file * added code for apache commons collection SetUtils * refactored example code
2017-06-26 23:18:54 +01:00
parent 75e0473822
commit 3ae96995ad
3 changed files with 96 additions and 4 deletions
@@ -0,0 +1,83 @@
+package com.baeldung.commons.collections;
+
+import org.apache.commons.collections4.SetUtils;
+import org.apache.commons.collections4.set.TransformedSet;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Created by smatt on 21/06/2017.
+ */
+public class SetUtilsUnitTest {
+
+    @Test(expected = IllegalArgumentException.class)
+    public void givenSetAndPredicate_whenPredicatedSet_thenValidateSet_and_throw_IllegalArgumentException() {
+        Set<String> sourceSet = new HashSet<>();
+        sourceSet.addAll(Arrays.asList("London", "Lagos", "Err Source1"));
+        Set<String> validatingSet
+          = SetUtils.predicatedSet(sourceSet, (s) -> s.startsWith("L"));
+        validatingSet.add("Err Source2");
+    }
+
+    @Test
+    public void givenTwoSets_whenDifference_thenSetView() {
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2));
+        SetUtils.SetView<Integer> result = SetUtils.difference(a, b);
+        assertTrue(result.size() == 1 && result.contains(5));
+    }
+
+    @Test
+    public void givenTwoSets_whenUnion_thenUnionResult() {
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2));
+        Set<Integer> expected = new HashSet<>(Arrays.asList(1,2,5));
+        SetUtils.SetView<Integer> union = SetUtils.union(a, b);
+        assertTrue(SetUtils.isEqualSet(expected, union));
+    }
+
+    @Test
+    public void givenTwoSets_whenIntersection_thenIntersectionResult() {
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2));
+        Set<Integer> expected = new HashSet<>(Arrays.asList(1,2));
+        SetUtils.SetView<Integer> intersect = SetUtils.intersection(a, b);
+        assertTrue(SetUtils.isEqualSet(expected, intersect));
+    }
+
+    @Test
+    public void givenSet_whenTransformedSet_thenTransformedResult() {
+        Set<Integer> a = SetUtils.transformedSet(new HashSet<>(), (e) -> e * 2  );
+        a.add(2);
+        assertEquals(a.toArray()[0], 4);
+
+        Set<Integer> source = new HashSet<>(Arrays.asList(1));
+        Set<Integer> newSet = TransformedSet.transformedSet(source, (e) -> e * 2);
+        assertEquals(newSet.toArray()[0], 2);
+        assertEquals(source.toArray()[0], 2);
+    }
+
+    @Test
+    public void givenTwoSet_whenDisjunction_thenDisjunctionSet() {
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2,3));
+        SetUtils.SetView<Integer> result = SetUtils.disjunction(a, b);
+        assertTrue(result.toSet().contains(5) && result.toSet().contains(3));
+    }
+
+    @Test
+    public void givenSet_when_OrderedSet_thenMaintainElementOrder() {
+        Set<Integer> set = new HashSet<>(Arrays.asList(10,1,5));
+        System.out.println("unordered set: " + set);
+
+        Set<Integer> orderedSet = SetUtils.orderedSet(new HashSet<>());
+        orderedSet.addAll(Arrays.asList(10,1,5));
+        System.out.println("ordered set = " + orderedSet);
+    }
+}