strategy pattern

src/main/java/core/basesyntax/DiscountStrategy.java

@@ -0,0 +1,22 @@
+package core.basesyntax;
+
+import core.basesyntax.strategy.DiscountService;
+import core.basesyntax.strategy.impl.BirthdayDiscountService;
+import core.basesyntax.strategy.impl.BlackFridayDiscountService;
+import core.basesyntax.strategy.impl.DefaultDiscountService;
+import core.basesyntax.strategy.impl.NewYearDiscountService;
+
+public class DiscountStrategy {
+    DiscountService getDiscountServiceBySpecialEvent(String specialEvent) {
+        switch (specialEvent) {
+            case "Birthday":
+                return new BirthdayDiscountService();
+            case "Black Friday":
+                return new BlackFridayDiscountService();
+            case "New Year":
+                return new NewYearDiscountService();
+            default:
+                return new DefaultDiscountService();
+        }
+    }
+}

src/main/java/core/basesyntax/strategy/DiscountService.java

@@ -0,0 +1,5 @@
+package core.basesyntax.strategy;
+
+public interface DiscountService {
+    double getDiscount();
+}

src/main/java/core/basesyntax/strategy/impl/BirthdayDiscountService.java

@@ -0,0 +1,12 @@
+package core.basesyntax.strategy.impl;
+
+import core.basesyntax.strategy.DiscountService;
+
+public class BirthdayDiscountService implements DiscountService {
+    private static final int BIRTHDAY_DISCOUNT = 33;
+
+    @Override
+    public double getDiscount() {
+        return BIRTHDAY_DISCOUNT;
+    }
+}

src/main/java/core/basesyntax/strategy/impl/BlackFridayDiscountService.java

@@ -0,0 +1,12 @@
+package core.basesyntax.strategy.impl;
+
+import core.basesyntax.strategy.DiscountService;
+
+public class BlackFridayDiscountService implements DiscountService {
+    private static final int BLACK_FRIDAY_DISCOUNT = 45;
+
+    @Override
+    public double getDiscount() {
+        return BLACK_FRIDAY_DISCOUNT;
+    }
+}

src/main/java/core/basesyntax/strategy/impl/DefaultDiscountService.java

@@ -0,0 +1,12 @@
+package core.basesyntax.strategy.impl;
+
+import core.basesyntax.strategy.DiscountService;
+
+public class DefaultDiscountService implements DiscountService {
+    private static final int DEFAULT_DISCOUNT = 0;
+
+    @Override
+    public double getDiscount() {
+        return DEFAULT_DISCOUNT;
+    }
+}

src/main/java/core/basesyntax/strategy/impl/NewYearDiscountService.java

@@ -0,0 +1,12 @@
+package core.basesyntax.strategy.impl;
+
+import core.basesyntax.strategy.DiscountService;
+
+public class NewYearDiscountService implements DiscountService {
+    private static final int NEW_YEAR_DISCOUNT = 20;
+
+    @Override
+    public double getDiscount() {
+        return NEW_YEAR_DISCOUNT;
+    }
+}