method extractions

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

@@ -9,7 +9,15 @@ public class AgedBrie implements CustomisedItem {
     }
 
     public void updateState() {
+        decreaseSellByDayValueByOne();
+        increaseQualityByOne();
+    }
+
+    private void decreaseSellByDayValueByOne() {
         item.sellIn -= 1;
+    }
+
+    private void increaseQualityByOne() {
         item.quality += 1;
     }
 }

Java/src/main/java/com/gildedrose/item/BackstagePassesItem.java

@@ -9,15 +9,31 @@ public class BackstagePassesItem implements CustomisedItem {
     }
 
     public void updateState() {
-        item.sellIn -= 1;
+        decreaseSellByDayValueByOne();
-        if (item.sellIn >= 11) {
+        if (sellByDayValueIsOver(10)) {
-            item.quality += 1;
+            increaseQualityBy(1);
-        } else if (item.sellIn > 5) {
+        } else if (sellByDayValueIsOver(5)) {
-            item.quality += 2;
+            increaseQualityBy(2);
-        } else if (item.sellIn > 0) {
+        } else if (sellByDayValueIsOver(0)) {
-            item.quality += 3;
+            increaseQualityBy(3);
         } else {
+            dropQualityToZero();
+        }
+    }
+
+    private void decreaseSellByDayValueByOne() {
+        item.sellIn -= 1;
+    }
+
+    private boolean sellByDayValueIsOver(int dayNumber) {
+        return item.sellIn > dayNumber;
+    }
+
+    private void increaseQualityBy(int qualityValue) {
+        item.quality += qualityValue;
+    }
+
+    private void dropQualityToZero() {
         item.quality = 0;
     }
 }
-}

Java/src/main/java/com/gildedrose/item/ConjuredItem.java

@@ -9,12 +9,23 @@ public class ConjuredItem implements CustomisedItem {
     }
 
     public void updateState() {
-        item.sellIn -= 1;
+        decreaseSellByDayValueByOne();
-        if (item.sellIn > 0) {
+        if (sellByDayValueIsOverZero()) {
-            item.quality -= 2;
+            decreaseQualityBy(2);
         } else {
-            item.quality -= 4;
+            decreaseQualityBy(4);
         }
     }
 
+    private void decreaseSellByDayValueByOne() {
+        item.sellIn -= 1;
+    }
+
+    private boolean sellByDayValueIsOverZero() {
+        return item.sellIn > 0;
+    }
+
+    private void decreaseQualityBy(int qualityValue) {
+        item.quality -= qualityValue;
+    }
 }

Java/src/main/java/com/gildedrose/item/StandardItem.java

@@ -9,13 +9,23 @@ public class StandardItem implements CustomisedItem {
     }
 
     public void updateState() {
-        item.sellIn -= 1;
+        decreaseSellByDayValueByOne();
-        if (item.sellIn > 0) {
+        if (sellByDayValueIsOverZero()) {
-            item.quality -= 1;
+            decreaseQualityBy(1);
         } else {
-            item.quality -= 2;
+            decreaseQualityBy(2);
         }
     }
 
-
+    private void decreaseSellByDayValueByOne() {
+        item.sellIn -= 1;
+    }
+
+    private boolean sellByDayValueIsOverZero() {
+        return item.sellIn > 0;
+    }
+
+    private void decreaseQualityBy(int qualityValue) {
+        item.quality -= qualityValue;
+    }
 }