feat: add PriceRange concept

TieredPricing constructor parallel change

Author: adrianliz

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/PriceRange.java

@@ -0,0 +1,28 @@
+package tv.codely.checkout;
+
+public final class PriceRange {
+
+    private final int numberOfSubscriptionsFrom;
+    private final int numberOfSubscriptionsTo;
+    private final double unitPrice;
+
+    public PriceRange(int numberOfSubscriptionsFrom, int numberOfSubscriptionsTo,
+        double unitPrice) {
+        this.numberOfSubscriptionsFrom = numberOfSubscriptionsFrom;
+        this.numberOfSubscriptionsTo = numberOfSubscriptionsTo;
+        this.unitPrice = unitPrice;
+    }
+
+    public boolean isInRange(int numberOfSubscriptions) {
+        return numberOfSubscriptions >= numberOfSubscriptionsFrom
+            && numberOfSubscriptions <= numberOfSubscriptionsTo;
+    }
+
+    public double unitPrice() {
+        return unitPrice;
+    }
+
+    public double getTotalPrice(int numberOfSubscriptions) {
+        return unitPrice * numberOfSubscriptions;
+    }
+}

exercises/tiered_pricing/solutions/adrianliz/java/src/main/java/tv/codely/checkout/TieredPricing.java

@@ -1,19 +1,28 @@
 package tv.codely.checkout;
 
+import java.util.List;
+
 public class TieredPricing {
 
-    public int getTotalPrice(int subscriptions) {
-        switch (subscriptions) {
-            case 1, 2:
-                return 299 * subscriptions;
-            case 3, 4, 5, 6, 7, 8, 9, 10:
-                return 239 * subscriptions;
-            case 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25:
-                return 219 * subscriptions;
-            case 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50:
-                return 199 * subscriptions;
-            default:
-                return 149 * subscriptions;
-        }
+    private final List<PriceRange> priceRanges;
+
+    public TieredPricing(final List<PriceRange> priceRanges) {
+        this.priceRanges = priceRanges;
+    }
+
+    public TieredPricing() {
+        this(List.of(
+            new PriceRange(1, 2, 299),
+            new PriceRange(3, 10, 239),
+            new PriceRange(11, 25, 219),
+            new PriceRange(26, 50, 199),
+            new PriceRange(51, 100, 149)));
+    }
+
+    public double getTotalPrice(int subscriptions) {
+        return priceRanges.stream().filter(priceRange -> priceRange.isInRange(subscriptions))
+            .findFirst()
+            .map(priceRange -> priceRange.getTotalPrice(subscriptions))
+            .orElse(0D);
     }
 }

exercises/tiered_pricing/solutions/adrianliz/java/src/test/java/tv/codely/checkout/TieredPricingShould.java

@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 public class TieredPricingShould {
@@ -12,6 +13,22 @@ void unit_test_example() {
         assertTrue(true);
     }
 
+    @Test
+    void return_total_price_based_on_number_of_subscriptions() {
+        final var priceRanges =
+            List.of(
+                new PriceRange(1, 2, 299),
+                new PriceRange(3, 10, 239),
+                new PriceRange(11, 25, 219),
+                new PriceRange(26, 50, 199),
+                new PriceRange(51, 100, 149));
+        final var tieredPricing = new TieredPricing(priceRanges);
+        final var expectedPrice = priceRanges.get(1).unitPrice() * 3;
+
+        final var totalPrice = tieredPricing.getTotalPrice(3);
+        assertEquals(expectedPrice, totalPrice);
+    }
+
     @Test
     void return_total_price_for_1_subscription() {
         final var tieredPricing = new TieredPricing();