BAEL-6212: rich domain model support

patterns-modules/clean-architecture/src/main/java/com/baeldung/pattern/richdomainmodel/Player.java

@@ -0,0 +1,35 @@
+package com.baeldung.pattern.richdomainmodel;
+
+public class Player {
+    private int points ;
+    final String name;
+
+    public Player(String name) {
+        this(name, 0);
+    }
+
+    private Player(String name, int points) {
+        this.name = name;
+        this.points = 0;
+    }
+
+    public void gainPoint() {
+        points++;
+    }
+
+    public boolean hasScoreBiggerThan(Score score) {
+        return this.points > score.points();
+    }
+
+    public int pointsDifference(Player other) {
+        return points - other.points;
+    }
+
+    public String name() {
+        return name;
+    }
+
+    public String score() {
+        return Score.from(points).label();
+    }
+}

patterns-modules/clean-architecture/src/main/java/com/baeldung/pattern/richdomainmodel/Score.java

@@ -0,0 +1,29 @@
+package com.baeldung.pattern.richdomainmodel;
+
+import java.util.Arrays;
+
+public enum Score {
+    LOVE(0, "Love"), FIFTEEN(1, "Fifteen"), THIRTY(2, "Thirty"), FORTY(3, "Forty");
+
+    private final int points;
+    private final String label;
+
+    Score(int points, String label) {
+        this.points = points;
+        this.label = label;
+    }
+
+    public static Score from(int value) {
+        return Arrays.stream(values())
+          .filter(v -> v.points == value)
+          .findFirst()
+          .orElseThrow(() -> new IllegalArgumentException("no such element: " + value));
+    }
+
+    public int points() {
+        return points;
+    }
+    public String label() {
+        return label;
+    }
+}

patterns-modules/clean-architecture/src/main/java/com/baeldung/pattern/richdomainmodel/TennisGame.java

@@ -0,0 +1,71 @@
+package com.baeldung.pattern.richdomainmodel;
+
+public class TennisGame {
+    private final Player server;
+    private final Player receiver;
+
+    public TennisGame(String server, String receiver) {
+        this.server = new Player(server);
+        this.receiver = new Player(receiver);
+    }
+
+    public void wonPoint(String playerName) {
+        if(server.name().equals(playerName)) {
+            server.gainPoint();
+        } else {
+            receiver.gainPoint();
+        }
+    }
+
+    public String getScore() {
+        if (gameContinues()) {
+            return getGameScore();
+        }
+        return "Win for " + leadingPlayer().name();
+    }
+
+    private String getGameScore() {
+        if (isScoreEqual()) {
+            return getEqualScore();
+        }
+        if (isAdvantage()) {
+            return "Advantage " + leadingPlayer().name();
+        }
+        return getSimpleScore();
+    }
+
+    private boolean isScoreEqual() {
+        return server.pointsDifference(receiver) == 0;
+    }
+
+    private boolean isAdvantage() {
+        return leadingPlayer().hasScoreBiggerThan(Score.FORTY)
+          && Math.abs(server.pointsDifference(receiver)) == 1;
+    }
+
+    private boolean isGameFinished() {
+        return leadingPlayer().hasScoreBiggerThan(Score.FORTY)
+          && Math.abs(server.pointsDifference(receiver)) >= 2;
+    }
+
+    private Player leadingPlayer() {
+        if (server.pointsDifference(receiver) > 0) {
+            return server;
+        }
+        return receiver;
+    }
+
+    private boolean gameContinues() {
+        return !isGameFinished();
+    }
+    private String getSimpleScore() {
+        return String.format("%s-%s", server.score(), receiver.score());
+    }
+
+    private String getEqualScore() {
+        if (server.hasScoreBiggerThan(Score.THIRTY)) {
+            return "Deuce";
+        }
+        return String.format("%s-All", server.score());
+    }
+}

patterns-modules/clean-architecture/src/test/java/com/baeldung/pattern/richdomainmodel/RichDomainModelUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.pattern.richdomainmodel;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+public class RichDomainModelUnitTest {
+
+    @Test
+    public void givenATennisGame_whenReceiverWinsThreePoints_thenScoreIsFortyLove() {
+        TennisGame game = new TennisGame("server", "receiver");
+
+        game.wonPoint("server");
+        game.wonPoint("server");
+        game.wonPoint("server");
+
+        assertThat(game.getScore())
+            .isEqualTo("Forty-Love");
+    }
+
+    @Test
+    public void givenATennisGame_whenEachPlayerWonTwoPoints_thenScoreIsThirtyAll() {
+        TennisGame game = new TennisGame("server", "receiver");
+
+        game.wonPoint("server");
+        game.wonPoint("server");
+        game.wonPoint("receiver");
+        game.wonPoint("receiver");
+
+        assertThat(game.getScore())
+            .isEqualTo("Thirty-All");
+    }
+}