Merge pull request #5454 from danielguedesb/master

BAEL-2242

core-java-collections/src/main/java/com/baeldung/removal/CollectionRemoveIf.java

@@ -0,0 +1,19 @@
+package com.baeldung.removal;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+public class CollectionRemoveIf {
+
+    public static void main(String args[]) {
+        Collection<String> names = new ArrayList<>();
+        names.add("John");
+        names.add("Ana");
+        names.add("Mary");
+        names.add("Anthony");
+        names.add("Mark");
+
+        names.removeIf(e -> e.startsWith("A"));
+        System.out.println(String.join(",", names));
+    }
+}

core-java-collections/src/main/java/com/baeldung/removal/Iterators.java

@@ -0,0 +1,28 @@
+package com.baeldung.removal;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+
+public class Iterators {
+
+    public static void main(String args[]) {
+        Collection<String> names = new ArrayList<>();
+        names.add("John");
+        names.add("Ana");
+        names.add("Mary");
+        names.add("Anthony");
+        names.add("Mark");
+
+        Iterator<String> i = names.iterator();
+
+        while (i.hasNext()) {
+            String e = i.next();
+            if (e.startsWith("A")) {
+                i.remove();
+            }
+        }
+
+        System.out.println(String.join(",", names));
+    }
+}

core-java-collections/src/main/java/com/baeldung/removal/StreamFilterAndCollector.java

@@ -0,0 +1,23 @@
+package com.baeldung.removal;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+public class StreamFilterAndCollector {
+
+    public static void main(String args[]) {
+        Collection<String> names = new ArrayList<>();
+        names.add("John");
+        names.add("Ana");
+        names.add("Mary");
+        names.add("Anthony");
+        names.add("Mark");
+
+        Collection<String> filteredCollection = names
+                .stream()
+                .filter(e -> !e.startsWith("A"))
+                .collect(Collectors.toList());
+        System.out.println(String.join(",", filteredCollection));
+    }
+}

core-java-collections/src/main/java/com/baeldung/removal/StreamPartitioningBy.java

@@ -0,0 +1,28 @@
+package com.baeldung.removal;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class StreamPartitioningBy {
+
+    public static void main(String args[]) {
+        Collection<String> names = new ArrayList<>();
+        names.add("John");
+        names.add("Ana");
+        names.add("Mary");
+        names.add("Anthony");
+        names.add("Mark");
+
+        Map<Boolean, List<String>> classifiedElements = names
+                .stream()
+                .collect(Collectors.partitioningBy((String e) -> !e.startsWith("A")));
+
+        String matching = String.join(",", classifiedElements.get(Boolean.TRUE));
+        String nonMatching = String.join(",", classifiedElements.get(Boolean.FALSE));
+        System.out.println("Matching elements: " + matching);
+        System.out.println("Non matching elements: " + nonMatching);
+    }
+}

core-java-collections/src/test/java/com/baeldung/removal/RemovalUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.removal;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+public class RemovalUnitTest {
+
+    Collection<String> names;
+    Collection<String> expected;
+    Collection<String> removed;
+
+    @Before
+    public void setupTestData() {
+        names = new ArrayList<>();
+        expected = new ArrayList<>();
+        removed = new ArrayList<>();
+
+        names.add("John");
+        names.add("Ana");
+        names.add("Mary");
+        names.add("Anthony");
+        names.add("Mark");
+
+        expected.add("John");
+        expected.add("Mary");
+        expected.add("Mark");
+
+        removed.add("Ana");
+        removed.add("Anthony");
+    }
+
+    @Test
+    public void givenCollectionOfNames_whenUsingIteratorToRemoveAllNamesStartingWithLetterA_finalListShouldContainNoNamesStartingWithLetterA() {
+        Iterator<String> i = names.iterator();
+
+        while (i.hasNext()) {
+            String e = i.next();
+            if (e.startsWith("A")) {
+                i.remove();
+            }
+        }
+
+        assertThat(names, is(expected));
+    }
+
+    @Test
+    public void givenCollectionOfNames_whenUsingRemoveIfToRemoveAllNamesStartingWithLetterA_finalListShouldContainNoNamesStartingWithLetterA() {
+        names.removeIf(e -> e.startsWith("A"));
+        assertThat(names, is(expected));
+    }
+
+    @Test
+    public void givenCollectionOfNames_whenUsingStreamToFilterAllNamesStartingWithLetterA_finalListShouldContainNoNamesStartingWithLetterA() {
+        Collection<String> filteredCollection = names
+                .stream()
+                .filter(e -> !e.startsWith("A"))
+                .collect(Collectors.toList());
+        assertThat(filteredCollection, is(expected));
+    }
+
+    @Test
+    public void givenCollectionOfNames_whenUsingStreamAndPartitioningByToFindNamesThatStartWithLetterA_shouldFind3MatchingAnd2NonMatching() {
+        Map<Boolean, List<String>> classifiedElements = names
+                .stream()
+                .collect(Collectors.partitioningBy((String e) -> !e.startsWith("A")));
+
+        assertThat(classifiedElements.get(Boolean.TRUE), is(expected));
+        assertThat(classifiedElements.get(Boolean.FALSE), is(removed));
+    }
+
+}