refactoring : middle man - replace subclass with delegate

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/Booking.java

@@ -0,0 +1,48 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate;
+
+import java.time.DayOfWeek;
+import java.time.LocalDateTime;
+
+public class Booking {
+
+    protected Show show;
+
+    protected LocalDateTime time;
+
+    protected PremiumDelegate premiumDelegate;
+
+    public Booking(Show show, LocalDateTime time) {
+        this.show = show;
+        this.time = time;
+    }
+
+    public static Booking createBooking(Show show, LocalDateTime time) {
+        return new Booking(show, time);
+    }
+
+    public static Booking createPremiumBooking(Show show, LocalDateTime time, PremiumExtra extra) {
+        Booking booking = createBooking(show, time);
+        booking.premiumDelegate = new PremiumDelegate(booking, extra);
+        return booking;
+    }
+
+    public boolean hasTalkback() {
+        return (this.premiumDelegate != null) ? this.premiumDelegate.hasTalkback() :
+                this.show.hasOwnProperty("talkback") && !this.isPeakDay();
+    }
+
+    protected boolean isPeakDay() {
+        DayOfWeek dayOfWeek = this.time.getDayOfWeek();
+        return dayOfWeek == DayOfWeek.SATURDAY || dayOfWeek == DayOfWeek.SUNDAY;
+    }
+
+    public double basePrice() {
+        double result = this.show.getPrice();
+        if (this.isPeakDay()) result += Math.round(result * 0.15);
+        return (this.premiumDelegate != null) ? this.premiumDelegate.extendBasePrice(result) : result;
+    }
+
+    public boolean hasDinner() {
+        return this.premiumDelegate != null && this.premiumDelegate.hasDinner();
+    }
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/PremiumDelegate.java

@@ -0,0 +1,24 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate;
+
+public class PremiumDelegate {
+
+    private Booking host;
+    private PremiumExtra extra;
+
+    public PremiumDelegate(Booking host, PremiumExtra extra) {
+        this.host = host;
+        this.extra = extra;
+    }
+
+    public boolean hasTalkback() {
+        return this.host.show.hasOwnProperty("talkback");
+    }
+
+    public double extendBasePrice(double result) {
+        return Math.round(result + this.extra.getPremiumFee());
+    }
+
+    public boolean hasDinner() {
+        return this.extra.hasOwnProperty("dinner") && !this.host.isPeakDay();
+    }
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/PremiumExtra.java

@@ -0,0 +1,23 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate;
+
+import java.util.List;
+
+public class PremiumExtra {
+
+    private List<String> properties;
+
+    private double premiumFee;
+
+    public PremiumExtra(List<String> properties, double premiumFee) {
+        this.properties = properties;
+        this.premiumFee = premiumFee;
+    }
+
+    public double getPremiumFee() {
+        return premiumFee;
+    }
+
+    public boolean hasOwnProperty(String property) {
+        return this.properties.contains(property);
+    }
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/Show.java

@@ -0,0 +1,23 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate;
+
+import java.util.List;
+
+public class Show {
+
+    private List<String> properties;
+
+    private double price;
+
+    public Show(List<String> properties, double price) {
+        this.properties = properties;
+        this.price = price;
+    }
+
+    public boolean hasOwnProperty(String property) {
+        return this.properties.contains(property);
+    }
+
+    public double getPrice() {
+        return price;
+    }
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/_before/Booking.java

@@ -0,0 +1,32 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate._before;
+
+import java.time.DayOfWeek;
+import java.time.LocalDateTime;
+
+public class Booking {
+
+    protected Show show;
+
+    protected LocalDateTime time;
+
+    public Booking(Show show, LocalDateTime time) {
+        this.show = show;
+        this.time = time;
+    }
+
+    public boolean hasTalkback() {
+        return this.show.hasOwnProperty("talkback") && !this.isPeakDay();
+    }
+
+    protected boolean isPeakDay() {
+        DayOfWeek dayOfWeek = this.time.getDayOfWeek();
+        return dayOfWeek == DayOfWeek.SATURDAY || dayOfWeek == DayOfWeek.SUNDAY;
+    }
+
+    public double basePrice() {
+        double result = this.show.getPrice();
+        if (this.isPeakDay()) result += Math.round(result * 0.15);
+        return result;
+    }
+
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/_before/PremiumBooking.java

@@ -0,0 +1,27 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate._before;
+
+import java.time.LocalDateTime;
+
+public class PremiumBooking extends Booking {
+
+    private PremiumExtra extra;
+
+    public PremiumBooking(Show show, LocalDateTime time, PremiumExtra extra) {
+        super(show, time);
+        this.extra = extra;
+    }
+
+    @Override
+    public boolean hasTalkback() {
+        return this.show.hasOwnProperty("talkback");
+    }
+
+    @Override
+    public double basePrice() {
+        return Math.round(super.basePrice() + this.extra.getPremiumFee());
+    }
+
+    public boolean hasDinner() {
+        return this.extra.hasOwnProperty("dinner") && !this.isPeakDay();
+    }
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/_before/PremiumExtra.java

@@ -0,0 +1,23 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate._before;
+
+import java.util.List;
+
+public class PremiumExtra {
+
+    private List<String> properties;
+
+    private double premiumFee;
+
+    public PremiumExtra(List<String> properties, double premiumFee) {
+        this.properties = properties;
+        this.premiumFee = premiumFee;
+    }
+
+    public double getPremiumFee() {
+        return premiumFee;
+    }
+
+    public boolean hasOwnProperty(String property) {
+        return this.properties.contains(property);
+    }
+}

refactoring/src/main/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/_before/Show.java

@@ -0,0 +1,23 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate._before;
+
+import java.util.List;
+
+public class Show {
+
+    private List<String> properties;
+
+    private double price;
+
+    public Show(List<String> properties, double price) {
+        this.properties = properties;
+        this.price = price;
+    }
+
+    public boolean hasOwnProperty(String property) {
+        return this.properties.contains(property);
+    }
+
+    public double getPrice() {
+        return price;
+    }
+}

refactoring/src/test/java/com/example/refactoring/_18_middle_man/_40_replace_subclass_with_delegate/BookingTest.java

@@ -0,0 +1,65 @@
+package com.example.refactoring._18_middle_man._40_replace_subclass_with_delegate;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookingTest {
+
+    @Test
+    void talkback() {
+        Show nonTalkbackShow = new Show(List.of(), 120);
+        Show talkbackShow = new Show(List.of("talkback"), 120);
+        LocalDateTime nonPeekDay = LocalDateTime.of(2022, 1, 20, 19, 0);
+        LocalDateTime peekDay = LocalDateTime.of(2022, 1, 15, 19, 0);
+
+        assertFalse(Booking.createBooking(nonTalkbackShow, nonPeekDay).hasTalkback());
+        assertTrue(Booking.createBooking(talkbackShow, nonPeekDay).hasTalkback());
+        assertFalse(Booking.createBooking(talkbackShow, peekDay).hasTalkback());
+
+        PremiumExtra premiumExtra = new PremiumExtra(List.of(), 50);
+        assertTrue(Booking.createPremiumBooking(talkbackShow, peekDay, premiumExtra).hasTalkback());
+        assertFalse(Booking.createPremiumBooking(nonTalkbackShow, peekDay, premiumExtra).hasTalkback());
+    }
+
+    @Test
+    void basePrice() {
+        Show lionKing = new Show(List.of(), 120);
+        LocalDateTime weekday = LocalDateTime.of(2022, 1, 20, 19, 0);
+
+        Booking booking = Booking.createBooking(lionKing, weekday);
+        assertEquals(120, booking.basePrice());
+
+        Booking premium = Booking.createPremiumBooking(lionKing, weekday, new PremiumExtra(List.of(), 50));
+        assertEquals(170, premium.basePrice());
+    }
+
+    @Test
+    void basePrice_on_peakDay() {
+        Show lionKing = new Show(List.of(), 120);
+        LocalDateTime weekend = LocalDateTime.of(2022, 1, 15, 19, 0);
+
+        Booking booking = Booking.createBooking(lionKing, weekend);
+        assertEquals(138, booking.basePrice());
+
+        Booking premium = Booking.createPremiumBooking(lionKing, weekend, new PremiumExtra(List.of(), 50));
+        assertEquals(188, premium.basePrice());
+    }
+
+    @Test
+    void hasDinner() {
+        Show lionKing = new Show(List.of(), 120);
+        LocalDateTime weekday = LocalDateTime.of(2022, 1, 20, 19, 0);
+        LocalDateTime weekend = LocalDateTime.of(2022, 1, 15, 19, 0);
+        PremiumExtra premiumExtra = new PremiumExtra(List.of("dinner"), 50);
+
+        assertTrue(Booking.createPremiumBooking(lionKing, weekday, premiumExtra).hasDinner());
+        assertFalse(Booking.createPremiumBooking(lionKing, weekend, premiumExtra).hasDinner());
+        assertFalse(Booking.createBooking(lionKing, weekend).hasDinner());
+        assertFalse(Booking.createBooking(lionKing, weekday).hasDinner());
+    }
+
+}