Refactoring Money

Author: kousiknath

src/com/lld/amazon/model/PricingGroup.java

@@ -1,5 +1,6 @@
 package com.lld.amazon.model;
 
+import com.lld.amazon.constant.CurrencySymbol;
 import com.lld.amazon.constant.PricingGroupType;
 import com.lld.amazon.exception.PricingException;
 
@@ -58,12 +59,12 @@ public void addPricingLineItem(PricingLineItem lineItem, PricingGroup baseGroup)
 
     private Double calculateTotal(PricingGroup baseGroup) throws PricingException {
         Double amount = 0D;
-        String symbol = null;
+        CurrencySymbol symbol = null;
 
         for (PricingLineItem lineItem: pricingLineItems) {
             if (symbol == null) {
-                symbol = lineItem.getCurrencySymbol();
-            } else if (!symbol.equals(lineItem.getCurrencySymbol())) {
+                symbol = lineItem.getAmount().getCurrencySymbol();
+            } else if (!symbol.equals(lineItem.getAmount().getCurrencySymbol())) {
                 throw new PricingException("Inconsistent symbols in pricing line items");
             }
 
@@ -81,8 +82,8 @@ private Double calculateTotal(PricingGroup baseGroup) throws PricingException {
                 }
             }
 
-            if (lineItem.getAmount() != null) {
-                amount += lineItem.getAmount();
+            if (lineItem.getAmount() != null && lineItem.getAmount().getAmount() != null) {
+                amount += lineItem.getAmount().getAmount();
             } else if (lineItem.getPercentageOfBaseAmount() != null) {
                 amount = amount + baseGroup.totalAmount * lineItem.getPercentageOfBaseAmount() * 0.01;
             }

src/com/lld/amazon/model/PricingLineItem.java

@@ -1,7 +1,5 @@
 package com.lld.amazon.model;
 
-import com.lld.amazon.constant.PricingLineItemType;
-
 import java.util.Objects;
 
 /*
@@ -10,36 +8,28 @@
  */
 public class PricingLineItem {
     private String name;
-    // If `amount` is specified, it will be directly used
-    // for computation
-    private Double amount;
     // If `amount` is unspecified, `percentageOfBaseAmount`
+    private Money amount;
     // will be used
     private Double percentageOfBaseAmount;
-    private String currencySymbol;
 
-    public PricingLineItem(String name, Double amount, String currencySymbol, Double percentageOfBaseAmount) {
+    public PricingLineItem(String name, Money amount, Double percentageOfBaseAmount) {
         this.name = name;
         this.amount = amount;
-        this.currencySymbol = currencySymbol;
         this.percentageOfBaseAmount = percentageOfBaseAmount;
     }
 
-    public Double getAmount() {
+    public Money getAmount() {
         return amount;
     }
 
     public Double getPercentageOfBaseAmount() {
         return percentageOfBaseAmount;
     }
 
-    public String getCurrencySymbol() {
-        return currencySymbol;
-    }
-
     @Override
     public int hashCode() {
-        return Objects.hash(name, currencySymbol);
+        return Objects.hash(name, this.amount.getCurrencySymbol().name());
     }
 
     @Override
@@ -54,6 +44,6 @@ public boolean equals(Object other) {
 
         PricingLineItem o = (PricingLineItem) other;
         return this.name.equals(o.name)
-                && this.currencySymbol.equals(o.currencySymbol);
+                && this.amount.getCurrencySymbol().name().equals(o.amount.getCurrencySymbol().name());
     }
 }

src/com/lld/amazon/service/impl/PricingServiceImpl.java

@@ -45,8 +45,7 @@ public PricingGroup registerPricingLineItemWithAmount(PricingGroup pricingGroup,
             throw new PricingException("Amount can not be null");
         }
 
-        PricingLineItem pricingLineItem = new PricingLineItem(lineItemName, money.getAmount(),
-                money.getCurrencySymbol().name(), null);
+        PricingLineItem pricingLineItem = new PricingLineItem(lineItemName, money, null);
         pricingGroup.addPricingLineItem(pricingLineItem, baseGroup);
 
         return pricingGroup;
@@ -76,8 +75,7 @@ public PricingGroup registerPricingLineItemWithPercentage(PricingGroup pricingGr
             throw new PricingException("Percentage of base amount can not be null");
         }
 
-        PricingLineItem pricingLineItem = new PricingLineItem(lineItemName, null, money.getCurrencySymbol().name(),
-                percentageOfBaseAmount);
+        PricingLineItem pricingLineItem = new PricingLineItem(lineItemName, money, percentageOfBaseAmount);
         pricingGroup.addPricingLineItem(pricingLineItem, baseGroup);
 
         return pricingGroup;