refactor conditional to polymorphism - Standard items

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

@@ -1,23 +1,12 @@
 package com.gildedrose;
 
-import com.gildedrose.core.InventoryRuleEngine;
+import com.gildedrose.core.rule.InventoryRuleEngine;
 import com.gildedrose.domain.item.Item;
 import com.gildedrose.domain.item.ItemAdapter;
 import com.gildedrose.domain.item.ItemAdapterSimpleFactory;
 
 class GildedRose {
 
-    public static final String AGED_BRIE = "Aged Brie";
-    public static final String BACKSTAGE_PASSES = "Backstage passes to a TAFKAL80ETC concert";
-    public static final String SULFURAS = "Sulfuras, Hand of Ragnaros";
-
-    public static final int MINIMUM_QUALITY = 0;
-    public static final int MAXIMUM_QUALITY = 50;
-
-    public static final int SELL_IN_DAY11 = 11;
-    public static final int SELL_IN_DAY6 = 6;
-    public static final int SELL_IN_EXPIRED = 0;
-
     Item[] items;
 
     public GildedRose(Item[] items) {
@@ -26,61 +15,8 @@ class GildedRose {
 
     public void updateQuality() {
         for (Item item : items) {
-            doUpdateQuality(item);
+            ItemAdapter itemAdapter = ItemAdapterSimpleFactory.createItemAdapter(item);
+            InventoryRuleEngine.applyUpdateRule(itemAdapter);
         }
     }
-
-    private void doUpdateQuality(Item item) {
-
-        boolean isAgedBrie = item.name.equals(AGED_BRIE);
-        boolean isBackstagePasses = item.name.equals(BACKSTAGE_PASSES);
-        boolean isSulfuras = item.name.equals(SULFURAS);
-        ItemAdapter itemAdapter = ItemAdapterSimpleFactory.createItemAdapter(item);
-
-        if (isAgedBrie) {
-            InventoryRuleEngine.applyUpdateRule(itemAdapter);
-        } else if (isBackstagePasses) {
-            InventoryRuleEngine.applyUpdateRule(itemAdapter);
-        } else if (isSulfuras) {
-            InventoryRuleEngine.applyUpdateRule(itemAdapter);
-        } else {
-            //standard item
-            if (shouldDecreaseQuality(item)) {
-                decreaseQuality(item);
-            }
-
-            decreaseDay(item);
-
-            if (isExpired(item)) {
-                if (shouldDecreaseQuality(item)) {
-                    decreaseQuality(item);
-                }
-            }
-        }
-    }
-
-    private boolean shouldDecreaseQuality(Item item) {
-        return item.quality > MINIMUM_QUALITY;
-    }
-
-    private boolean shouldIncreaseQuality(Item item) {
-        return item.quality < MAXIMUM_QUALITY;
-    }
-
-    private void decreaseDay(Item item) {
-        item.sellIn = item.sellIn - 1;
-    }
-
-    private boolean isExpired(Item item) {
-        return item.sellIn < SELL_IN_EXPIRED;
-    }
-
-    private void decreaseQuality(Item item) {
-        item.quality = item.quality - 1;
-    }
-
-    private void increaseQuality(Item item) {
-        item.quality = item.quality + 1;
-    }
-
 }

Java/src/main/java/com/gildedrose/application/agedbrie/AgedBrieRule.java

@@ -1,6 +1,6 @@
 package com.gildedrose.application.agedbrie;
 
-import com.gildedrose.core.rules.UpdateInventoryTemplateRule;
+import com.gildedrose.core.rule.UpdateInventoryTemplateRule;
 import com.gildedrose.domain.item.ItemAdapter;
 
 public class AgedBrieRule extends UpdateInventoryTemplateRule {

Java/src/main/java/com/gildedrose/application/backstagepasses/BackstagePassesRule.java

@@ -1,6 +1,6 @@
 package com.gildedrose.application.backstagepasses;
 
-import com.gildedrose.core.rules.UpdateInventoryTemplateRule;
+import com.gildedrose.core.rule.UpdateInventoryTemplateRule;
 import com.gildedrose.domain.item.ItemAdapter;
 
 public class BackstagePassesRule extends UpdateInventoryTemplateRule {

Java/src/main/java/com/gildedrose/application/standard/StandardItemRule.java

@@ -0,0 +1,27 @@
+package com.gildedrose.application.standard;
+
+import com.gildedrose.core.rule.UpdateInventoryTemplateRule;
+import com.gildedrose.domain.item.ItemAdapter;
+
+public class StandardItemRule extends UpdateInventoryTemplateRule {
+
+    @Override
+    protected boolean canSubtractSellIn(final ItemAdapter itemAdapter) {
+        return true;
+    }
+
+    @Override
+    protected int getQualityFactor(final boolean isExpired, final ItemAdapter itemAdapter) {
+        return isExpired ? 2 : 1;
+    }
+
+    @Override
+    protected boolean canIncreaseQuality(boolean isExpired, final ItemAdapter itemAdapter) {
+        return false;
+    }
+
+    @Override
+    protected boolean canDecreaseQuality(boolean isExpired, final ItemAdapter itemAdapter) {
+        return true;
+    }
+}

Java/src/main/java/com/gildedrose/application/sulfuras/SulfurasRule.java

@@ -1,6 +1,6 @@
 package com.gildedrose.application.sulfuras;
 
-import com.gildedrose.core.rules.UpdateInventoryTemplateRule;
+import com.gildedrose.core.rule.UpdateInventoryTemplateRule;
 import com.gildedrose.domain.item.ItemAdapter;
 
 public class SulfurasRule extends UpdateInventoryTemplateRule {

Java/src/main/java/com/gildedrose/core/rule/InventoryRuleEngine.java

@@ -1,9 +1,9 @@
-package com.gildedrose.core;
+package com.gildedrose.core.rule;
 
 import com.gildedrose.application.agedbrie.AgedBrieRule;
 import com.gildedrose.application.backstagepasses.BackstagePassesRule;
+import com.gildedrose.application.standard.StandardItemRule;
 import com.gildedrose.application.sulfuras.SulfurasRule;
-import com.gildedrose.core.rules.UpdateInventoryTemplateRule;
 import com.gildedrose.domain.item.ItemAdapter;
 import com.gildedrose.domain.item.ItemType;
 
@@ -16,6 +16,7 @@ public class InventoryRuleEngine {
         put(ItemType.AGEG_BRIE, new AgedBrieRule());
         put(ItemType.SULFURAS, new SulfurasRule());
         put(ItemType.BACKSTAGE_PASSES, new BackstagePassesRule());
+        put(ItemType.STANDARD, new StandardItemRule());
     }};
 
     public static void applyUpdateRule(ItemAdapter itemAdapter) {

Java/src/main/java/com/gildedrose/core/rule/UpdateInventoryTemplateRule.java

@@ -1,4 +1,4 @@
-package com.gildedrose.core.rules;
+package com.gildedrose.core.rule;
 
 import com.gildedrose.domain.item.ItemAdapter;
 

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

@@ -1,71 +0,0 @@
-package com.gildedrose;
-
-import com.gildedrose.domain.item.Item;
-import org.junit.jupiter.api.Test;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-class GildedRoseTest {
-
-    //GENERAL RULES
-    @Test
-    void whenSellInDateIsPassed_qualityDegradesTwiceAsFast() {
-        //given
-        Item testItem = new Item("standard item", 0, 3);
-        Item[] items = new Item[] {testItem};
-
-        //when
-        GildedRose app = new GildedRose(items);
-        app.updateQuality();
-
-        //then
-        assertEquals(-1, app.items[0].sellIn);
-        assertEquals(1, app.items[0].quality);
-    }
-
-    @Test
-    void qualityOfAnItemIsNeverNegative() {
-        //given
-        Item testItem = new Item("standard item", 0, 0);
-        Item[] items = new Item[] {testItem};
-
-        //when
-        GildedRose app = new GildedRose(items);
-        app.updateQuality();
-
-        //then
-        assertEquals(-1, app.items[0].sellIn);
-        assertEquals(0, app.items[0].quality);
-    }
-
-    @Test
-    void qualityOfAnItemIsNeverMoreThan50() {
-        //given
-        Item testItem = new Item("standard item", 5, 50);
-        Item[] items = new Item[] {testItem};
-
-        //when
-        GildedRose app = new GildedRose(items);
-        app.updateQuality();
-
-        //then
-        assertEquals(4, app.items[0].sellIn);
-        assertEquals(50, app.items[0].quality);
-    }
-
-    @Test
-    void standardItemQualityDecreasesByOne() {
-        //given
-        Item testItem = new Item("standard item", 5, 2);
-        Item[] items = new Item[] {testItem};
-
-        //when
-        GildedRose app = new GildedRose(items);
-        app.updateQuality();
-
-        //then
-        assertEquals(4, app.items[0].sellIn);
-        assertEquals(1, app.items[0].quality);
-    }
-
-}

Java/src/test/java/com/gildedrose/application/aggedbrie/AgedBrieRuleTest.java

@@ -39,4 +39,34 @@ public class AgedBrieRuleTest {
         assertEquals(-1, agedBrieAdapter.getItem().sellIn);
         assertEquals(4, agedBrieAdapter.getItem().quality);
     }
+
+    @Test
+    void agedBrieQualityIncreasesNoMoreThan50() {
+        //given
+        Item agedBrie = new Item("Aged Brie", 5, 50);
+        ItemAdapter agedBrieAdapter = new ItemAdapter(ItemType.AGEG_BRIE, agedBrie);
+        AgedBrieRule agedBrieRule = new AgedBrieRule();
+
+        //when
+        agedBrieRule.processItem(agedBrieAdapter);
+
+        //then
+        assertEquals(4, agedBrieAdapter.getItem().sellIn);
+        assertEquals(50, agedBrieAdapter.getItem().quality);
+    }
+
+    @Test
+    void agedBrieQualityIncreasesNoMoreThan50WhenIsExpired() {
+        //given
+        Item agedBrie = new Item("Aged Brie", 0, 50);
+        ItemAdapter agedBrieAdapter = new ItemAdapter(ItemType.AGEG_BRIE, agedBrie);
+        AgedBrieRule agedBrieRule = new AgedBrieRule();
+
+        //when
+        agedBrieRule.processItem(agedBrieAdapter);
+
+        //then
+        assertEquals(-1, agedBrieAdapter.getItem().sellIn);
+        assertEquals(50, agedBrieAdapter.getItem().quality);
+    }
 }

Java/src/test/java/com/gildedrose/application/backstagepasses/BackstagePassesRuleTest.java

@@ -68,4 +68,49 @@ public class BackstagePassesRuleTest {
         assertEquals(-1, backstageAdapter.getItem().sellIn);
         assertEquals(0, backstageAdapter.getItem().quality);
     }
+
+    @Test
+    void backStageQualityIncreasesNoMoreThan50WhenThereAre5DaysOrLess() {
+        //given
+        Item backStage5 = new Item("Backstage passes to a TAFKAL80ETC concert", 5, 50);
+        ItemAdapter backstageAdapter = new ItemAdapter(ItemType.BACKSTAGE_PASSES, backStage5);
+        BackstagePassesRule backstagePassesRule = new BackstagePassesRule();
+
+        //when
+        backstagePassesRule.processItem(backstageAdapter);
+
+        //then
+        assertEquals(4, backstageAdapter.getItem().sellIn);
+        assertEquals(50, backstageAdapter.getItem().quality);
+    }
+
+    @Test
+    void backStageQualityIncreasesNoMoreThan50WhenThereAre10DaysOrLess() {
+        //given
+        Item backStage5 = new Item("Backstage passes to a TAFKAL80ETC concert", 10, 50);
+        ItemAdapter backstageAdapter = new ItemAdapter(ItemType.BACKSTAGE_PASSES, backStage5);
+        BackstagePassesRule backstagePassesRule = new BackstagePassesRule();
+
+        //when
+        backstagePassesRule.processItem(backstageAdapter);
+
+        //then
+        assertEquals(9, backstageAdapter.getItem().sellIn);
+        assertEquals(50, backstageAdapter.getItem().quality);
+    }
+
+    @Test
+    void backStageQualityIncreasesNoMoreThan50WhenIsGreaterThan10Days() {
+        //given
+        Item backStage5 = new Item("Backstage passes to a TAFKAL80ETC concert", 11, 50);
+        ItemAdapter backstageAdapter = new ItemAdapter(ItemType.BACKSTAGE_PASSES, backStage5);
+        BackstagePassesRule backstagePassesRule = new BackstagePassesRule();
+
+        //when
+        backstagePassesRule.processItem(backstageAdapter);
+
+        //then
+        assertEquals(10, backstageAdapter.getItem().sellIn);
+        assertEquals(50, backstageAdapter.getItem().quality);
+    }
 }

Java/src/test/java/com/gildedrose/application/standard/StandardItemRuleTest.java

@@ -0,0 +1,56 @@
+package com.gildedrose.application.standard;
+
+import com.gildedrose.domain.item.Item;
+import com.gildedrose.domain.item.ItemAdapter;
+import com.gildedrose.domain.item.ItemType;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class StandardItemRuleTest {
+
+    @Test
+    void whenSellInDateIsPassed_qualityDegradesTwiceAsFast() {
+        //given
+        Item testItem = new Item("standard item", 0, 3);
+        ItemAdapter itemAdapter = new ItemAdapter(ItemType.STANDARD, testItem);
+        StandardItemRule standardItemRule = new StandardItemRule();
+
+        //when
+        standardItemRule.processItem(itemAdapter);
+
+        //then
+        assertEquals(-1, itemAdapter.getItem().sellIn);
+        assertEquals(1, itemAdapter.getItem().quality);
+    }
+
+    @Test
+    void qualityOfAnItemIsNeverNegative() {
+        //given
+        Item testItem = new Item("standard item", 0, 0);
+        ItemAdapter itemAdapter = new ItemAdapter(ItemType.STANDARD, testItem);
+        StandardItemRule standardItemRule = new StandardItemRule();
+
+        //when
+        standardItemRule.processItem(itemAdapter);
+
+        //then
+        assertEquals(-1, itemAdapter.getItem().sellIn);
+        assertEquals(0, itemAdapter.getItem().quality);
+    }
+
+    @Test
+    void standardItemQualityDecreasesByOne() {
+        //given
+        Item testItem = new Item("standard item", 5, 2);
+        ItemAdapter itemAdapter = new ItemAdapter(ItemType.STANDARD, testItem);
+        StandardItemRule standardItemRule = new StandardItemRule();
+
+        //when
+        standardItemRule.processItem(itemAdapter);
+
+        //then
+        assertEquals(4, itemAdapter.getItem().sellIn);
+        assertEquals(1, itemAdapter.getItem().quality);
+    }
+}

Java/src/test/java/com/gildedrose/core/rule/InventoryRuleEngineTest.java

@@ -1,4 +1,4 @@
-package com.gildedrose.core;
+package com.gildedrose.core.rule;
 
 import com.gildedrose.domain.item.Item;
 import com.gildedrose.domain.item.ItemAdapter;

Java/src/test/java/com/gildedrose/core/rule/UpdateInventoryTemplateRuleTest.java

@@ -1,4 +1,4 @@
-package com.gildedrose.core.rules;
+package com.gildedrose.core.rule;
 
 import com.gildedrose.domain.item.Item;
 import com.gildedrose.domain.item.ItemAdapter;