diff --git a/core-java-collections/pom.xml b/core-java-collections/pom.xml index a5aea49c14..d63f4d2a45 100644 --- a/core-java-collections/pom.xml +++ b/core-java-collections/pom.xml @@ -36,15 +36,32 @@ commons-lang3 ${commons-lang3.version} + + org.eclipse.collections + eclipse-collections-api + 9.2.0 + + + org.eclipse.collections + eclipse-collections + 9.2.0 + org.assertj assertj-core ${assertj.version} test + + org.junit.platform + junit-platform-runner + ${junit.platform.version} + test + + 1.2.0 3.5 4.1 4.01 diff --git a/core-java-collections/src/main/java/com/baeldung/java/filtering/CollectionUtilsCollectionFilter.java b/core-java-collections/src/main/java/com/baeldung/java/filtering/CollectionUtilsCollectionFilter.java new file mode 100644 index 0000000000..4d6a3d62fd --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/java/filtering/CollectionUtilsCollectionFilter.java @@ -0,0 +1,22 @@ +package com.baeldung.java.filtering; + +import java.util.Collection; + +import org.apache.commons.collections4.CollectionUtils; +import org.apache.commons.collections4.Predicate; + +public class CollectionUtilsCollectionFilter { + + static public Collection findEvenNumbers(Collection baseCollection) { + Predicate apacheEventNumberPredicate = new Predicate() { + + @Override + public boolean evaluate(Integer object) { + return object % 2 == 0; + } + }; + + CollectionUtils.filter(baseCollection, apacheEventNumberPredicate); + return baseCollection; + } +} diff --git a/core-java-collections/src/main/java/com/baeldung/java/filtering/EclipseCollectionsCollectionFilter.java b/core-java-collections/src/main/java/com/baeldung/java/filtering/EclipseCollectionsCollectionFilter.java new file mode 100644 index 0000000000..981d6ca241 --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/java/filtering/EclipseCollectionsCollectionFilter.java @@ -0,0 +1,32 @@ +package com.baeldung.java.filtering; + +import java.util.Collection; + +import org.eclipse.collections.api.block.predicate.Predicate; +import org.eclipse.collections.impl.factory.Lists; +import org.eclipse.collections.impl.utility.Iterate; + +public class EclipseCollectionsCollectionFilter { + + static public Collection findEvenNumbers(Collection baseCollection) { + Predicate eclipsePredicate = item -> item % 2 == 0; + Collection filteredList = Lists.mutable.ofAll(baseCollection) + .select(eclipsePredicate); + + return filteredList; + } + + static public Collection findEvenNumbersUsingIterate(Collection baseCollection) { + Predicate eclipsePredicate = new Predicate() { + private static final long serialVersionUID = 1L; + + @Override + public boolean accept(Integer arg0) { + return arg0 % 2 == 0; + } + }; + Collection filteredList = Iterate.select(baseCollection, eclipsePredicate); + + return filteredList; + } +} diff --git a/core-java-collections/src/main/java/com/baeldung/java/filtering/GuavaCollectionFilter.java b/core-java-collections/src/main/java/com/baeldung/java/filtering/GuavaCollectionFilter.java new file mode 100644 index 0000000000..f5a27f0bdb --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/java/filtering/GuavaCollectionFilter.java @@ -0,0 +1,22 @@ +package com.baeldung.java.filtering; + +import java.util.Collection; + +import com.google.common.base.Predicate; +import com.google.common.collect.Collections2; + +public class GuavaCollectionFilter { + + static public Collection findEvenNumbers(Collection baseCollection) { + Predicate guavaPredicate = new Predicate() { + + @Override + public boolean apply(Integer input) { + return input % 2 == 0; + } + }; + Collection filteredCollection = Collections2.filter(baseCollection, guavaPredicate); + return filteredCollection; + } + +} diff --git a/core-java-collections/src/main/java/com/baeldung/java/filtering/StreamsCollectionFilter.java b/core-java-collections/src/main/java/com/baeldung/java/filtering/StreamsCollectionFilter.java new file mode 100644 index 0000000000..d51283de55 --- /dev/null +++ b/core-java-collections/src/main/java/com/baeldung/java/filtering/StreamsCollectionFilter.java @@ -0,0 +1,37 @@ +package com.baeldung.java.filtering; + +import java.util.Collection; +import java.util.function.Predicate; +import java.util.stream.Collectors; + +public class StreamsCollectionFilter { + + public static Collection filterCollectionHelperMethod(Collection baseCollection, Predicate predicate) { + return baseCollection.stream() + .filter(predicate) + .collect(Collectors.toList()); + } + + static public Collection findEvenNumbersUsingHelperMethod(Collection baseCollection) { + return filterCollectionHelperMethod(baseCollection, item -> item % 2 == 0); + } + + static public Collection findEvenNumbersUsingLambda(Collection baseCollection) { + return baseCollection.stream() + .filter(item -> item % 2 == 0) + .collect(Collectors.toList()); + } + + static public Collection findEvenNumbersUsingPredicate(Collection baseCollection) { + Predicate evenNumberPredicate = new Predicate() { + @Override + public boolean test(Integer i) { + return i % 2 == 0; + } + }; + + return baseCollection.stream() + .filter(evenNumberPredicate) + .collect(Collectors.toList()); + } +} diff --git a/core-java-collections/src/test/java/com/baeldung/java/filtering/CollectionFiltersUnitTest.java b/core-java-collections/src/test/java/com/baeldung/java/filtering/CollectionFiltersUnitTest.java new file mode 100644 index 0000000000..c85b7a526d --- /dev/null +++ b/core-java-collections/src/test/java/com/baeldung/java/filtering/CollectionFiltersUnitTest.java @@ -0,0 +1,46 @@ +package com.baeldung.java.filtering; + +import static org.assertj.core.api.Assertions.assertThat; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collection; + +import org.junit.jupiter.api.Test; +import org.junit.platform.runner.JUnitPlatform; +import org.junit.runner.RunWith; + +@RunWith(JUnitPlatform.class) +public class CollectionFiltersUnitTest { + + private static final Collection BASE_INTEGER_COLLECTION = Arrays.asList(9, 14, 2, 7, 1, 5, 8); + private static final Collection EXPECTED_EVEN_FILTERED_COLLECTION = Arrays.asList(14, 2, 8); + + @Test + public void givenAStringCollection_whenFilteringFourLetterWords_thenObtainTheFilteredCollection() { + final Collection baseStrings = Arrays.asList("java", "baeldung", "type", "example", "other"); + + Collection filtered = StreamsCollectionFilter.filterCollectionHelperMethod(baseStrings, item -> item.length() == 4); + + assertThat(filtered).containsExactlyInAnyOrder("java", "type"); + } + + @Test + public void givenAnIntegerCollection_whenFilteringEvenValues_thenObtainTheFilteredCollectionForAllCases() { + Collection filteredWithStreams1 = StreamsCollectionFilter.findEvenNumbersUsingLambda(BASE_INTEGER_COLLECTION); + Collection filteredWithStreams2 = StreamsCollectionFilter.findEvenNumbersUsingPredicate(BASE_INTEGER_COLLECTION); + Collection filteredWithCollectionUtils = CollectionUtilsCollectionFilter.findEvenNumbers(new ArrayList<>(BASE_INTEGER_COLLECTION)); + Collection filteredWithEclipseCollections = EclipseCollectionsCollectionFilter.findEvenNumbers(BASE_INTEGER_COLLECTION); + Collection filteredWithEclipseCollectionsUsingIterate = EclipseCollectionsCollectionFilter.findEvenNumbersUsingIterate(BASE_INTEGER_COLLECTION); + Collection filteredWithGuava = GuavaCollectionFilter.findEvenNumbers(BASE_INTEGER_COLLECTION); + + assertThat(filteredWithStreams1).hasSameElementsAs(filteredWithStreams2) + .hasSameElementsAs(filteredWithCollectionUtils) + .hasSameElementsAs(filteredWithEclipseCollections) + .hasSameElementsAs(filteredWithEclipseCollectionsUsingIterate) + .hasSameElementsAs(filteredWithEclipseCollectionsUsingIterate) + .hasSameElementsAs(filteredWithGuava) + .hasSameElementsAs(EXPECTED_EVEN_FILTERED_COLLECTION); + } + +}