Merge branch 'master' of https://github.com/rvsathe/tutorials

core-java-modules/core-java-12/README.md

@@ -2,3 +2,4 @@
 
 - [String API Updates in Java 12](https://www.baeldung.com/java12-string-api)
 - [New Features in Java 12](https://www.baeldung.com/java-12-new-features)
+- [Compare the Content of Two Files in Java](https://www.baeldung.com/java-compare-files)

core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/mapmulti/Album.java

@@ -0,0 +1,49 @@
+package com.baeldung.java_16_features.mapmulti;
+
+import java.util.List;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+
+public class Album {
+
+    private String albumName;
+    private int albumCost;
+    private List<Artist> artists;
+
+    Album(String name, int albumCost, List<Artist> artists) {
+        this.albumName = name;
+        this.artists = artists;
+        this.albumCost = albumCost;
+    }
+
+    public void artistAlbumPairsToMajorLabels(Consumer<Pair<String, String>> consumer) {
+
+        for (Artist artist : artists) {
+            if (artist.isAssociatedMajorLabels()) {
+                String concatLabels = artist.getMajorLabels()
+                    .stream()
+                    .collect(Collectors.joining(","));
+                consumer.accept(new ImmutablePair<>(artist.getName() + ":" + albumName, concatLabels));
+            }
+        }
+    }
+
+    public String getAlbumName() {
+        return albumName;
+    }
+
+    public int getAlbumCost() {
+        return albumCost;
+    }
+
+    List<Artist> getArtists() {
+        return artists;
+    }
+
+    public String toString() {
+        return albumName;
+    }
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/mapmulti/Artist.java

@@ -0,0 +1,50 @@
+package com.baeldung.java_16_features.mapmulti;
+
+import java.util.List;
+import java.util.Objects;
+
+public class Artist {
+
+    private final String name;
+    private boolean associatedMajorLabels;
+    private List<String> majorLabels;
+
+    Artist(String name, boolean associatedMajorLabels, List<String> majorLabels) {
+        this.name = name;
+        this.associatedMajorLabels = associatedMajorLabels;
+        this.majorLabels = majorLabels;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public boolean isAssociatedMajorLabels() {
+        return associatedMajorLabels;
+    }
+
+    public List<String> getMajorLabels() {
+        return majorLabels;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Artist other = (Artist) obj;
+        return Objects.equals(name, other.name);
+    }
+
+    public String toString() {
+        return name;
+    }
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/java_16_features/mapmulti/JavaStreamMapMultiUnitTest.java

@@ -0,0 +1,134 @@
+package com.baeldung.java_16_features.mapmulti;
+
+import static java.util.stream.Collectors.toList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.offset;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import org.junit.jupiter.api.Test;
+
+public class JavaStreamMapMultiUnitTest {
+
+    private static final List<Album> albums = Arrays.asList(new Album("album1", 10, Arrays.asList(new Artist("bob", true, Arrays.asList("label1", "label3")), new Artist("tom", true, Arrays.asList("label2", "label3")))),
+        new Album("album2", 20, Arrays.asList(new Artist("bill", true, Arrays.asList("label2", "label3")), new Artist("tom", true, Arrays.asList("label2", "label4")))));
+
+    @Test
+    public void givenAListOfintegers_whenMapMulti_thenGetListOfOfEvenDoublesPlusPercentage() {
+
+        List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5);
+        double percentage = .01;
+        List<Double> evenDoubles = integers.stream()
+            .<Double> mapMulti((integer, consumer) -> {
+                if (integer % 2 == 0) {
+                    consumer.accept((double) integer * (1 + percentage));
+                }
+            })
+            .collect(toList());
+
+        assertThat(evenDoubles).containsAll(Arrays.asList(2.02D, 4.04D));
+    }
+
+    @Test
+    public void givenAListOfintegers_whenFilterMap_thenGetListOfOfEvenDoublesPlusPercentage() {
+
+        List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5);
+        double percentage = .01;
+        List<Double> evenDoubles = integers.stream()
+            .filter(integer -> integer % 2 == 0)
+            .<Double> map(integer -> ((double) integer * (1 + percentage)))
+            .collect(toList());
+
+        assertThat(evenDoubles).containsAll(Arrays.asList(2.02D, 4.04D));
+    }
+
+    @Test
+    public void givenAListOfintegers_whenMapMultiToDouble_thenGetSumOfEvenNumbersAfterApplyPercentage() {
+
+        List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
+        double percentage = .01;
+        double sum = integers.stream()
+            .mapMultiToDouble((integer, consumer) -> {
+                if (integer % 2 == 0) {
+                    consumer.accept(integer * (1 + percentage));
+                }
+            })
+            .sum();
+
+        assertThat(sum).isEqualTo(12.12, offset(0.001d));
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenFlatMap_thenGetListOfArtistAlbumPairs() {
+
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .flatMap(album -> album.getArtists()
+                .stream()
+                .map(artist -> new ImmutablePair<String, String>(artist.getName(), album.getAlbumName())))
+            .collect(toList());
+
+        assertThat(artistAlbum).contains(new ImmutablePair<String, String>("bob", "album1"), new ImmutablePair<String, 
+            String>("tom", "album1"), new ImmutablePair<String, String>("bill", "album2"), new ImmutablePair<String, String>("tom", "album2"));
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenMapMulti_thenGetListOfPairsOfArtistAlbum() {
+
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .<Pair<String, String>> mapMulti((album, consumer) -> {
+                for (Artist artist : album.getArtists()) {
+                    consumer.accept(new ImmutablePair<String, String>(artist.getName(), album.getAlbumName()));
+                }
+            })
+            .collect(toList());
+
+        assertThat(artistAlbum).contains(new ImmutablePair<String, String>("bob", "album1"), new ImmutablePair<String, String>("tom", "album1"), 
+            new ImmutablePair<String, String>("bill", "album2"), new ImmutablePair<String, String>("tom", "album2"));
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenFlatMap_thenGetListOfArtistAlbumjPairsBelowGivenCost() {
+
+        int upperCost = 9;
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .flatMap(album -> album.getArtists()
+                .stream()
+                .filter(artist -> upperCost > album.getAlbumCost())
+                .map(artist -> new ImmutablePair<String, String>(artist.getName(), album.getAlbumName())))
+            .collect(toList());
+
+        assertTrue(artistAlbum.isEmpty());
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenMapMulti_thenGetListOfArtistAlbumPairsBelowGivenCost() {
+
+        int upperCost = 9;
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .<Pair<String, String>> mapMulti((album, consumer) -> {
+                if (album.getAlbumCost() < upperCost) {
+                    for (Artist artist : album.getArtists()) {
+                        consumer.accept(new ImmutablePair<String, String>(artist.getName(), album.getAlbumName()));
+                    }
+                }
+            })
+            .collect(toList());
+
+        assertTrue(artistAlbum.isEmpty());
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenMapMulti_thenGetPairsOfArtistMajorLabelsUsingMethodReference() {
+
+        List<Pair<String, String>> artistLabels = albums.stream()
+            .mapMulti(Album::artistAlbumPairsToMajorLabels)
+            .collect(toList());
+
+        assertThat(artistLabels).contains(new ImmutablePair<String, String>("bob:album1", "label1,label3"), new ImmutablePair<String, String>("tom:album1", "label2,label3"), 
+            new ImmutablePair<String, String>("bill:album2", "label2,label3"), new ImmutablePair<String, String>("tom:album2", "label2,label4"));
+    }
+}

core-java-modules/core-java-datetime-string/README.md

@@ -11,3 +11,4 @@ This module contains articles about parsing and formatting Java date and time ob
 - [Display All Time Zones With GMT And UTC in Java](http://www.baeldung.com/java-time-zones)
 - [Convert between String and Timestamp](https://www.baeldung.com/java-string-to-timestamp)
 - [Convert String to Date in Java](http://www.baeldung.com/java-string-to-date)
+- [Format a Milliseconds Duration to HH:MM:SS](https://www.baeldung.com/java-ms-to-hhmmss)

core-java-modules/core-java-datetime-string/pom.xml

@@ -75,7 +75,7 @@
 
     <properties>
         <commons-validator.version>1.6</commons-validator.version>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.10.10</joda-time.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <maven.compiler.source>1.9</maven.compiler.source>

core-java-modules/core-java-datetime-string/src/test/java/com/baeldung/formatduration/FormatDurationUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.formatduration;
+
+import org.apache.commons.lang3.time.DurationFormatUtils;
+import org.joda.time.Period;
+import org.junit.Test;
+
+import java.time.Duration;
+import java.util.concurrent.TimeUnit;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class FormatDurationUnitTest {
+
+
+    @Test
+    public void givenInterval_WhenFormatInterval_formatDuration() {
+        long HH = TimeUnit.MILLISECONDS.toHours(38114000);
+        long MM = TimeUnit.MILLISECONDS.toMinutes(38114000) % 60;
+        long SS = TimeUnit.MILLISECONDS.toSeconds(38114000) % 60;
+        String timeInHHMMSS = String.format("%02d:%02d:%02d", HH, MM, SS);
+
+        assertThat(timeInHHMMSS).isEqualTo("10:35:14");
+    }
+
+    @Test
+    public void givenInterval_WhenFormatUsingDuration_formatDuration() {
+        Duration duration = Duration.ofMillis(38114000);
+        long seconds = duration.getSeconds();
+        long HH = seconds / 3600;
+        long MM = (seconds % 3600) / 60;
+        long SS = seconds % 60;
+        String timeInHHMMSS =  String.format("%02d:%02d:%02d", HH, MM, SS);
+        assertThat(timeInHHMMSS).isEqualTo("10:35:14");
+    }
+
+
+    @Test
+    public void givenInterval_WhenFormatDurationUsingApacheCommons_formatDuration() {
+        assertThat(DurationFormatUtils.formatDuration(38114000, "HH:mm:ss"))
+          .isEqualTo("10:35:14");
+    }
+
+    @Test
+    public void givenInterval_WhenFormatDurationUsingJodaTime_formatDuration() {
+        org.joda.time.Duration duration = new org.joda.time.Duration(38114000);
+        Period period = duration.toPeriod();
+        long HH = period.getHours();
+        long MM = period.getMinutes();
+        long SS = period.getSeconds();
+
+        String timeInHHMMSS = String.format("%02d:%02d:%02d", HH, MM, SS);
+        assertThat(timeInHHMMSS).isEqualTo("10:35:14");
+    }
+}