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remove nulls from list #3

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remove nulls from list #3

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39 changes: 28 additions & 11 deletions src/test/java/com/levelup/java/collections/FilterNullFromCollection.java
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
import static org.junit.Assert.assertThat;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
Expand All @@ -27,11 +28,12 @@
* @author Justin Musgrove
* @see <a href='http://www.leveluplunch.com/java/examples/remove-filter-null-references-from-collection-list/'>Filter null from collection</a>
*/
@SuppressWarnings("SuspiciousMethodCalls")
public class FilterNullFromCollection {


@Test
public void remove_null_from_list_java () {
public void remove_null_from_mutable_list_java() {

List<String> strings = new ArrayList<>();
strings.add(null);
Expand All @@ -45,28 +47,43 @@ public void remove_null_from_list_java () {

assertEquals(3, strings.size());
}


@Test(expected = UnsupportedOperationException.class)
public void try_remove_null_from_immutable_list_java() {

List<String> strings = Arrays.asList(null, "www", null, "leveluplunch", "com", null);

strings.removeAll(Collections.singleton(null));
}

@Test
public void remove_null_from_immutable_list_java() {

List<String> strings = Arrays.asList(null, "www", null, "leveluplunch", "com", null);

List<String> filterStrings = new ArrayList<String>(strings) {
{
removeAll(Collections.singleton(null));
}
};

assertEquals(3, filterStrings.size());
}

@Test
public void remove_null_from_list_java8_lambda () {

List<String> strings = Lists.newArrayList(
null, "www", null,
null, "www", null,
"leveluplunch", "com", null);

List<String> filterStrings = strings
.stream()
.filter(p -> p != null)
.collect(Collectors.toList());

assertEquals(3, filterStrings.size());

// or
List<String> filterStrings2 = strings
.stream()
.filter(Objects::nonNull)
.collect(Collectors.toList());

assertEquals(3, filterStrings2.size());
assertEquals(3, filterStrings.size());
}


Expand Down