refactor code to have responsibility to respective items

Java/src/main/java/com/gildedrose/GildedRose.java

@@ -1,6 +1,7 @@
 package com.gildedrose;
 
-import static com.gildedrose.Constants.MAX_QUALITY;
+import com.gildedrose.model.Goods;
+
 import static com.gildedrose.Constants.MIN_QUALITY;
 
 class GildedRose {
@@ -12,79 +13,16 @@ class GildedRose {
     }
 
     public void updateQuality() {
-        for (Item item : items) {
-            if (item.name.equals("Conjured Mana Cake")) {
-                updateQualityForConjured(item);
-            } else
-                updateQuality(item);
+
+        for (Integer i = 0; i < items.length; i++) {
+            Goods goods = updateQuality(items[i]);
+            items[i] = goods; //TODO: remove mutation
         }
     }
 
-    private void updateQualityForConjured(Item item) {
-        if (item.sellIn > 0) {
-            item.quality = degradeQualityBy(item.quality, 2);
-        } else {
-            item.quality = degradeQualityBy(item.quality, 4);
-        }
-        item.sellIn = item.sellIn - 1;
-    }
-
-    private void updateQuality(Item item) {
-        if (!item.name.equals("Aged Brie")
-            && !item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-            if (item.quality > 0) {
-                if (!item.name.equals("Sulfuras, Hand of Ragnaros")) {
-                    item.quality = degradeQualityBy(item.quality, 1);
-                }
-            }
-        } else {
-            if (item.quality < 50) {
-                item.quality = item.quality + 1;
-
-                if (item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                    if (item.sellIn < 11) {
-                        if (item.quality < 50) {
-                            item.quality = upgradeQualityBy(item.quality, 1);
-                        }
-                    }
-
-                    if (item.sellIn < 6) {
-                        if (item.quality < 50) {
-                            item.quality = upgradeQualityBy(item.quality, 1);
-                        }
-                    }
-                }
-            }
-        }
-
-        if (!item.name.equals("Sulfuras, Hand of Ragnaros")) {
-            item.sellIn = item.sellIn - 1;
-        }
-
-        if (item.sellIn < 0) {
-            if (!item.name.equals("Aged Brie")) {
-                if (!item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                    if (item.quality > 0) {
-                        if (!item.name.equals("Sulfuras, Hand of Ragnaros")) {
-                            item.quality = degradeQualityBy(item.quality, 1);
-                        }
-                    }
-                } else {
-                    item.quality = 0;
-                }
-            } else {
-                if (item.quality < 50) {
-                    item.quality = item.quality + 1;
-                }
-            }
-        }
-    }
-
-    private Integer degradeQualityBy(int currentQuality, int degradeBy) {
-        return Math.max(currentQuality - degradeBy, MIN_QUALITY);
-    }
-
-    private Integer upgradeQualityBy(int currentQuality, int upgradeBy) {
-        return Math.min(currentQuality + upgradeBy, MAX_QUALITY);
+    private Goods updateQuality(Item item) {
+        Goods goods = GoodsFactory.getGoods(item.name, item.sellIn, item.quality);
+        goods.updateQuality();
+        return goods;
     }
 }

Java/src/main/java/com/gildedrose/GoodsFactory.java

@@ -0,0 +1,23 @@
+package com.gildedrose;
+
+import com.gildedrose.model.*;
+
+public class GoodsFactory {
+
+    public static Goods getGoods(String name, int initialSellIn, int initialQuality) {
+
+        switch (name) {
+            case "Aged Brie":
+                return new AgedBrie(initialSellIn, initialQuality);
+            case "Conjured Mana Cake":
+                return new Conjured(initialSellIn, initialQuality);
+            case "Sulfuras, Hand of Ragnaros":
+                return new Sulfuras(initialSellIn, initialQuality);
+            case "Backstage passes to a TAFKAL80ETC concert":
+                return new BackstagePasses(initialSellIn, initialQuality);
+            default:
+                return new NormalItem(name, initialSellIn, initialQuality);
+        }
+
+    }
+}

Java/src/main/java/com/gildedrose/Item.java

@@ -14,8 +14,8 @@ public class Item {
         this.quality = quality;
     }
 
-   @Override
-   public String toString() {
+    @Override
+    public String toString() {
         return this.name + ", " + this.sellIn + ", " + this.quality;
     }
 }

Java/src/main/java/com/gildedrose/model/AgedBrie.java

@@ -0,0 +1,28 @@
+package com.gildedrose.model;
+
+import static com.gildedrose.Constants.MAX_QUALITY;
+
+public class AgedBrie extends Goods {
+
+    public static final String AGED_BRIE = "Aged Brie";
+
+    public AgedBrie(int sellIn, int quality) {
+        super(AGED_BRIE, sellIn, quality);
+    }
+
+    @Override
+    public void updateQuality() {
+
+        sellInPasses();
+        upgradeQuality();
+        if (sellIn < 0) {
+            upgradeQuality();
+        }
+
+    }
+
+    private void upgradeQuality() {
+        quality = Math.min(quality + 1, MAX_QUALITY);
+    }
+
+}

Java/src/main/java/com/gildedrose/model/BackstagePasses.java

@@ -0,0 +1,40 @@
+package com.gildedrose.model;
+
+import static com.gildedrose.Constants.MAX_QUALITY;
+import static com.gildedrose.Constants.MIN_QUALITY;
+
+public class BackstagePasses extends Goods{
+
+    public BackstagePasses( int sellIn, int quality) {
+        super("Backstage passes to a TAFKAL80ETC concert", sellIn, quality);
+    }
+
+    @Override
+    public void updateQuality() {
+
+        if(isSellInLessThanOrEquals(0)) {
+                degradeQualityToZero();
+        }
+        else if(isSellInLessThanOrEquals(5)) {
+            upgradeQuality(3);
+        }
+        else if (isSellInLessThanOrEquals(10)) {
+            upgradeQuality(2);
+        } else {
+            upgradeQuality(1);
+        }
+        sellInPasses();
+    }
+
+    private boolean isSellInLessThanOrEquals(int numberOfDays) {
+        return sellIn <= numberOfDays;
+    }
+
+    private void upgradeQuality(int byValue) {
+        quality =  Math.min(quality + byValue, MAX_QUALITY);
+    }
+
+    private void degradeQualityToZero() {
+        quality = MIN_QUALITY;
+    }
+}

Java/src/main/java/com/gildedrose/model/Conjured.java

@@ -0,0 +1,24 @@
+package com.gildedrose.model;
+
+import static com.gildedrose.Constants.MIN_QUALITY;
+
+public class Conjured extends Goods {
+
+    public Conjured(int sellIn, int quality) {
+        super("Conjured Mana Cake", sellIn, quality);
+    }
+
+    @Override
+    public void updateQuality() {
+        if (sellIn > 0) {
+            degradeQualityBy(2);
+        } else {
+            degradeQualityBy(4);
+        }
+        sellInPasses();
+    }
+
+    private void degradeQualityBy(int degradeBy) {
+        quality = Math.max(quality - degradeBy, MIN_QUALITY);
+    }
+}

Java/src/main/java/com/gildedrose/model/Goods.java

@@ -0,0 +1,15 @@
+package com.gildedrose.model;
+
+import com.gildedrose.Item;
+
+public abstract class Goods extends Item {
+    public Goods(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+
+    public abstract void updateQuality();
+
+    public void sellInPasses() {
+        sellIn = sellIn - 1;
+    }
+}

Java/src/main/java/com/gildedrose/model/NormalItem.java

@@ -0,0 +1,23 @@
+package com.gildedrose.model;
+
+import static com.gildedrose.Constants.MIN_QUALITY;
+
+public class NormalItem extends Goods {
+
+    public NormalItem(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+
+    @Override
+    public void updateQuality() {
+        sellInPasses();
+        degradeQuality();
+        if (sellIn < 0) {
+            degradeQuality();
+        }
+    }
+
+    private void degradeQuality() {
+        quality = Math.max(quality - 1, MIN_QUALITY);
+    }
+}

Java/src/main/java/com/gildedrose/model/Sulfuras.java

@@ -0,0 +1,13 @@
+package com.gildedrose.model;
+
+public class Sulfuras extends Goods {
+
+    public Sulfuras(int sellIn, int quality) {
+        super("Sulfuras, Hand of Ragnaros", sellIn, quality);
+    }
+
+    @Override
+    public void updateQuality() {
+        // do  nothing
+    }
+}

Java/src/test/java/com/gildedrose/GildedRoseTest.java

@@ -1,6 +1,5 @@
 package com.gildedrose;
 
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;

Java/src/test/java/com/gildedrose/TexttestFixture.java

@@ -4,17 +4,17 @@ public class TexttestFixture {
     public static void main(String[] args) {
         System.out.println("OMGHAI!");
 
-        Item[] items = new Item[] {
-                new Item("+5 Dexterity Vest", 10, 20), //
-                new Item("Aged Brie", 2, 0), //
-                new Item("Elixir of the Mongoose", 5, 7), //
-                new Item("Sulfuras, Hand of Ragnaros", 0, 80), //
-                new Item("Sulfuras, Hand of Ragnaros", -1, 80),
-                new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20),
-                new Item("Backstage passes to a TAFKAL80ETC concert", 10, 49),
-                new Item("Backstage passes to a TAFKAL80ETC concert", 5, 49),
-                // this conjured item does not work properly yet
-                new Item("Conjured Mana Cake", 3, 6) };
+        Item[] items = new Item[]{
+            new Item("+5 Dexterity Vest", 10, 20), //
+            new Item("Aged Brie", 2, 0), //
+            new Item("Elixir of the Mongoose", 5, 7), //
+            new Item("Sulfuras, Hand of Ragnaros", 0, 80), //
+            new Item("Sulfuras, Hand of Ragnaros", -1, 80),
+            new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20),
+            new Item("Backstage passes to a TAFKAL80ETC concert", 10, 49),
+            new Item("Backstage passes to a TAFKAL80ETC concert", 5, 49),
+            // this conjured item does not work properly yet
+            new Item("Conjured Mana Cake", 3, 6)};
 
         GildedRose app = new GildedRose(items);
 

Java/src/test/java/com/gildedrose/model/AgedBrieTest.java

@@ -0,0 +1,39 @@
+package com.gildedrose.model;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class AgedBrieTest {
+
+
+    private static Stream<Arguments> provideInputWhereSellInDayPassesByOneDay() {
+
+        return Stream.of(
+
+            // 3. Aged Brie
+            // 3.a Before sellIn
+            Arguments.of(new AgedBrie(2, 0), "Aged Brie", 1, 1),
+            Arguments.of(new AgedBrie(1, 0), "Aged Brie", 0, 1),
+            Arguments.of(new AgedBrie(1, 50), "Aged Brie", 0, 50),
+
+            //3.b After sellIn
+            Arguments.of(new AgedBrie(0, 50), "Aged Brie", -1, 50),
+            Arguments.of(new AgedBrie(0, 48), "Aged Brie", -1, 50));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInputWhereSellInDayPassesByOneDay")
+    void shouldDegradeQualityForAnItem(AgedBrie agedBrie, String expectedName, int expectedSellIn, int expectedQuality) {
+        agedBrie.updateQuality();
+        assertEquals(expectedName, agedBrie.name);
+        assertEquals(expectedSellIn, agedBrie.sellIn);
+        assertEquals(expectedQuality, agedBrie.quality);
+    }
+
+}
+

Java/src/test/java/com/gildedrose/model/BackstagePassesTest.java

@@ -0,0 +1,37 @@
+package com.gildedrose.model;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BackstagePassesTest {
+
+    private static Stream<Arguments> provideInputWhereSellInDayPassesByOneDay() {
+
+        return Stream.of(
+
+            //5. "Backstage passes to a TAFKAL80ETC concert"
+            //5.a Before sellIn
+            Arguments.of(new BackstagePasses(15, 20), "Backstage passes to a TAFKAL80ETC concert", 14, 21),
+            Arguments.of(new BackstagePasses(10, 49), "Backstage passes to a TAFKAL80ETC concert", 9, 50),
+            Arguments.of(new BackstagePasses(10, 49), "Backstage passes to a TAFKAL80ETC concert", 9, 50),
+            Arguments.of(new BackstagePasses(10, 48), "Backstage passes to a TAFKAL80ETC concert", 9, 50),
+            Arguments.of(new BackstagePasses(5, 47), "Backstage passes to a TAFKAL80ETC concert", 4, 50),
+
+            //5.b After sellIn
+            Arguments.of(new BackstagePasses(0, 47), "Backstage passes to a TAFKAL80ETC concert", -1, 0));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInputWhereSellInDayPassesByOneDay")
+    void shouldDegradeQualityForAnItem(BackstagePasses backstagePasses, String expectedName, int expectedSellIn, int expectedQuality) {
+        backstagePasses.updateQuality();
+        assertEquals(expectedName, backstagePasses.name);
+        assertEquals(expectedSellIn, backstagePasses.sellIn);
+        assertEquals(expectedQuality, backstagePasses.quality);
+    }
+}

Java/src/test/java/com/gildedrose/model/ConjuredTest.java

@@ -0,0 +1,36 @@
+package com.gildedrose.model;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ConjuredTest {
+
+    private static Stream<Arguments> provideInputWhereSellInDayPassesByOneDay() {
+
+        return Stream.of(
+
+            //2. Conjured item
+            //2.a Before sellIn
+            Arguments.of(new Conjured(1, 10), "Conjured Mana Cake", 0, 8),
+            Arguments.of(new Conjured(1, 0), "Conjured Mana Cake", 0, 0),
+
+            //2.b After sellIn
+            Arguments.of(new Conjured(0, 0), "Conjured Mana Cake", -1, 0),
+            Arguments.of(new Conjured(0, 10), "Conjured Mana Cake", -1, 6));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInputWhereSellInDayPassesByOneDay")
+    void shouldDegradeQualityForAnItem(Conjured conjured, String expectedName, int expectedSellIn, int expectedQuality) {
+        conjured.updateQuality();
+        assertEquals(expectedName, conjured.name);
+        assertEquals(expectedSellIn, conjured.sellIn);
+        assertEquals(expectedQuality, conjured.quality);
+    }
+
+}

Java/src/test/java/com/gildedrose/model/NormalItemTest.java

@@ -0,0 +1,38 @@
+package com.gildedrose.model;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class NormalItemTest {
+
+    private static Stream<Arguments> provideInputWhereSellInDayPassesByOneDay() {
+
+        return Stream.of(
+
+            // 1. Normal Item
+            // 1.a Before sellIn
+            Arguments.of(new NormalItem("Normal Item", 1, 0), "Normal Item", 0, 0),
+            Arguments.of(new NormalItem("Normal Item", 1, 10), "Normal Item", 0, 9),
+
+            //1.b After sellIn
+            Arguments.of(new NormalItem("Normal Item", 0, 0), "Normal Item", -1, 0),
+            Arguments.of(new NormalItem("Normal Item", 0, 10), "Normal Item", -1, 8));
+
+
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInputWhereSellInDayPassesByOneDay")
+    void shouldDegradeQualityForAnItem(NormalItem normalItem, String expectedName, int expectedSellIn, int expectedQuality) {
+        normalItem.updateQuality();
+        assertEquals(expectedName, normalItem.name);
+        assertEquals(expectedSellIn, normalItem.sellIn);
+        assertEquals(expectedQuality, normalItem.quality);
+    }
+
+}

Java/src/test/java/com/gildedrose/model/SulfurasTest.java

@@ -0,0 +1,36 @@
+package com.gildedrose.model;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class SulfurasTest {
+
+    private static Stream<Arguments> provideInputWhereSellInDayPassesByOneDay() {
+
+        return Stream.of(
+
+            //4."Sulfuras, Hand of Ragnaros"
+
+            //4.a before sellIn
+            Arguments.of(new Sulfuras(10, 80), "Sulfuras, Hand of Ragnaros", 10, 80),
+
+            //4.b after sellIn
+            Arguments.of(new Sulfuras(0, 80), "Sulfuras, Hand of Ragnaros", 0, 80),
+            Arguments.of(new Sulfuras(-1, 80), "Sulfuras, Hand of Ragnaros", -1, 80));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInputWhereSellInDayPassesByOneDay")
+    void shouldDegradeQualityForAnItem(Sulfuras sulfuras, String expectedName, int expectedSellIn, int expectedQuality) {
+        sulfuras.updateQuality();
+        assertEquals(expectedName, sulfuras.name);
+        assertEquals(expectedSellIn, sulfuras.sellIn);
+        assertEquals(expectedQuality, sulfuras.quality);
+    }
+
+}