Added comments

amazingkart/src/main/java/com/amazingkart/api/API.java

@@ -1,31 +1,72 @@
 package com.amazingkart.api;
 
+import java.nio.file.Paths;
 import java.util.List;
 import java.util.Optional;
 
 import com.amazingkart.AmazingKartException;
 import com.amazingkart.Services.DataLoaderService;
 import com.amazingkart.dataStore.ProductStore;
 import com.amazingkart.pojo.Product;
+import com.amazingkart.promotions.PromotionSet;
 import com.amazingkart.promotions.Promotions;
 import com.amazingkart.util.JSONConverter;
 
 public class API {
 
-	public static void main(String[] args) {
+	private static final String OUTPUT_JSON_FILE_NAME = "output.json";
+	private static final String TARGET = "target";
 
+	/*
+	 * This is main method, As a part of main method we call following steps 1)
+	 * Validate and parse input to the program 2) It loads Product/currency rates
+	 * data in memory 3) It applies promotion rules on all the product 4) Finally
+	 * saves the products list in json file.
+	 */
+	public static void main(String[] args) {
 		try {
-			Optional<Promotions> promotion = Promotions.getValue(args[0]);
-			if (!promotion.isPresent()) {
-				throw new AmazingKartException("Invalid input parameter : " + args[0]);
-			}
-			DataLoaderService.getInstance().loadExchangeRates();
-			DataLoaderService.getInstance().loadProductDetails();
-			List<Product> applyPromotion = promotion.get().getPromotionObject().applyPromotion(ProductStore.getInstance().getProducts());
-			new  JSONConverter<Product>().writeToJsonFile("output.json", applyPromotion);
+			Promotions promotion = validateAndReadInput(args);
+			loadDataInMemory();
+			List<Product> updatedJSON = applyPromotion(promotion);
+			writeToOutputFile(updatedJSON);
 		} catch (AmazingKartException e) {
 			e.printStackTrace();
 		}
 
 	}
+
+	/* Writes the data back to json file */
+	private static void writeToOutputFile(List<Product> applyPromotion) throws AmazingKartException {
+		try {
+			new JSONConverter<Product>().writeToJsonFile(
+					Paths.get(TARGET, OUTPUT_JSON_FILE_NAME).toUri().toURL().getFile(), applyPromotion);
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+
+	/* Applies the mentioned promotion on all products */
+	private static List<Product> applyPromotion(Promotions promotion) throws AmazingKartException {
+		PromotionSet promotionObject = promotion.getPromotionObject();
+		List<Product> applyPromotion = promotionObject.applyPromotion(ProductStore.getInstance().getProducts());
+		return applyPromotion;
+	}
+
+	/* Loads product and currency data into memory */
+	private static void loadDataInMemory() throws AmazingKartException {
+		DataLoaderService.getInstance().loadExchangeRates();
+		DataLoaderService.getInstance().loadProductDetails();
+	}
+
+	/* Input Validations */
+	private static Promotions validateAndReadInput(String[] args) throws AmazingKartException {
+		if (args.length < 1 || args.length > 1) {
+			throw new AmazingKartException("Invalid input parameter : " + args[0]);
+		}
+		Optional<Promotions> promotion = Promotions.getValue(args[0]);
+		if (!promotion.isPresent()) {
+			throw new AmazingKartException("Invalid input parameter : " + args[0]);
+		}
+		return promotion.get();
+	}
 }

amazingkart/src/main/java/com/amazingkart/dataStore/ProductStore.java

@@ -6,6 +6,10 @@
 import com.amazingkart.pojo.Product;
 import com.amazingkart.util.CurrencyConverter;
 
+/* *
+ * @ProductStore is the class which stores product
+ * details fetched from web api
+ * */
 public class ProductStore {
 
 	private static ProductStore productStore = new ProductStore();

amazingkart/src/main/java/com/amazingkart/dataStore/RateStore.java

@@ -3,6 +3,10 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/* *
+ * @RateStore is the class which stores currency rates
+ * details fetched from web api
+ * */
 public class RateStore {
 
 	private static RateStore excahgenRateStore = new RateStore();

amazingkart/src/main/java/com/amazingkart/importer/http/HttpJsonResponseFetcher.java

@@ -19,12 +19,5 @@ public List<Product> fetchJSONResponse(String productDetailsUrl, Type type) thro
 		return new JSONConverter<Product>().convertJsonToObject(HttpClient.fetchResponse(productDetailsUrl), type);
 	}
 
-	/*public Map fetchJSONResponseIntoMap(String url) throws AmazingKartException {
-		return (Map) new JSONConverter<T>().convertJsonToObject(HttpClient.fetchResponse(url));
-	}
-	*/
-
-
-
 
 }

amazingkart/src/main/java/com/amazingkart/promotions/Condition.java

@@ -10,83 +10,90 @@
 import com.amazingkart.AmazingKartException;
 import com.amazingkart.pojo.Product;
 
+/*Condition class object corresponds to 
+ * the discount condition which can be applicable 
+ * on the product*/
 class Condition {
-		enum COMPARISON_OPERATOR {
+	enum COMPARISON_OPERATOR {
 		EQUAL, IN, GREATER_THAN, LESS_THAN;
 	}
 
-		private String variableName;
-		private List<Object> values;
-		private Condition.COMPARISON_OPERATOR operator; 
-
-		Condition(String productVariable, Condition.COMPARISON_OPERATOR operator, Object[] values) {
-			this.operator =operator; 	
-			this.variableName = productVariable;
-			this.values = Arrays.asList(values);
-		}
-
-		@SuppressWarnings({ "unchecked", "rawtypes" })
-		public boolean runCondition(Product product) throws AmazingKartException {
-			PropertyDescriptor pd;
-			try {
-				pd = new PropertyDescriptor(getVariableName(), Product.class);
-
-				Method getter = pd.getReadMethod();
-				switch (operator) {
-				case EQUAL:
-					if ((values.get(0)).equals(getter.invoke(product))) {
-						return true;
-					}
-					break;
-				case IN:
-					if (values.contains(getter.invoke(product))) {
-						return true;
-					}
-					break;
-				case GREATER_THAN:
-					if (((Comparable) getter.invoke(product)).compareTo(values.get(0)) > 0) {
-						return true;
-					}
-					break;
-
-				case LESS_THAN:
-					if (((Comparable) getter.invoke(product)).compareTo(values.get(0)) < 0) {
-						return true;
-					}
-					break;
-
-				default:
-					return false;
+	private String variableName;
+	private List<Object> values;
+	private Condition.COMPARISON_OPERATOR operator;
+
+	Condition(String productVariable, Condition.COMPARISON_OPERATOR operator, Object[] values) {
+		this.operator = operator;
+		this.variableName = productVariable;
+		this.values = Arrays.asList(values);
+	}
+
+	/*
+	 * runCondition method checks if the discount condition is applicable on the
+	 * product
+	 */
+	@SuppressWarnings({ "unchecked", "rawtypes" })
+	public boolean runCondition(Product product) throws AmazingKartException {
+		PropertyDescriptor pd;
+		try {
+			pd = new PropertyDescriptor(getVariableName(), Product.class);
+
+			Method getter = pd.getReadMethod();
+			switch (operator) {
+			case EQUAL:
+				if ((values.get(0)).equals(getter.invoke(product))) {
+					return true;
+				}
+				break;
+			case IN:
+				if (values.contains(getter.invoke(product))) {
+					return true;
 				}
-			} catch (SecurityException | IllegalArgumentException | InvocationTargetException | IllegalAccessException
-					| IntrospectionException e) {
-				throw new AmazingKartException("Exception occured while applying discount", e);
+				break;
+			case GREATER_THAN:
+				if (((Comparable) getter.invoke(product)).compareTo(values.get(0)) > 0) {
+					return true;
+				}
+				break;
+
+			case LESS_THAN:
+				if (((Comparable) getter.invoke(product)).compareTo(values.get(0)) < 0) {
+					return true;
+				}
+				break;
+
+			default:
+				return false;
 			}
-			return false;
-		}
-
-		public Condition.COMPARISON_OPERATOR getCondition() {
-			return operator;
+		} catch (SecurityException | IllegalArgumentException | InvocationTargetException | IllegalAccessException
+				| IntrospectionException e) {
+			throw new AmazingKartException("Exception occured while applying discount", e);
 		}
+		return false;
+	}
 
-		public void setCondition(Condition.COMPARISON_OPERATOR operator) {
-			this.operator = operator;
-		}
+	public Condition.COMPARISON_OPERATOR getCondition() {
+		return operator;
+	}
 
-		public List<Object> getValues() {
-			return values;
-		}
+	public void setCondition(Condition.COMPARISON_OPERATOR operator) {
+		this.operator = operator;
+	}
 
-		public void setValues(List<Object> values) {
-			this.values = values;
-		}
+	public List<Object> getValues() {
+		return values;
+	}
 
-		public String getVariableName() {
-			return variableName;
-		}
+	public void setValues(List<Object> values) {
+		this.values = values;
+	}
 
-		public void setVariableName(String variableName) {
-			this.variableName = variableName;
-		}
+	public String getVariableName() {
+		return variableName;
+	}
+
+	public void setVariableName(String variableName) {
+		this.variableName = variableName;
+	}
 
-	}
+}

amazingkart/src/main/java/com/amazingkart/promotions/DiscountRule.java

@@ -4,6 +4,9 @@
 import com.amazingkart.pojo.Discount;
 import com.amazingkart.pojo.Product;
 
+/*DiscountRule object corresponds to the discount condition 
+ * and amount/ percentage of discount 
+ * that can be applied on product*/
 public class DiscountRule {
 
 	enum DISCOUNT_TYPE {
@@ -21,7 +24,8 @@ enum CONDITION_GROUP_LOGIC_OPERATOR {
 	private CONDITION_GROUP_LOGIC_OPERATOR operator;
 	private CONDITION_GROUP_LOGIC_OPERATOR group_LOGIC_OPERATOR;
 
-	public DiscountRule(DISCOUNT_TYPE discount_type, Double discount, String discountTag, CONDITION_GROUP_LOGIC_OPERATOR group_LOGIC_OPERATOR, Condition []condition) {
+	public DiscountRule(DISCOUNT_TYPE discount_type, Double discount, String discountTag,
+			CONDITION_GROUP_LOGIC_OPERATOR group_LOGIC_OPERATOR, Condition[] condition) {
 		super();
 		this.discount_type = discount_type;
 		this.discount = discount;
@@ -30,21 +34,24 @@ public DiscountRule(DISCOUNT_TYPE discount_type, Double discount, String discoun
 		this.group_LOGIC_OPERATOR = group_LOGIC_OPERATOR;
 	}
 
-
 	private double applyDiscount(Double amount) {
 		if (DISCOUNT_TYPE.PERCENTAGE.equals(discount_type)) {
 			return amount * (discount / 100);
 		} else {
 			return discount;
 		}
 	}
-
+
+	/*
+	 * This method applies the discount rule on product and returns the amount of
+	 * discount that can be applied
+	 */
 	public Discount applyDiscountRule(Product product) throws AmazingKartException {
 		Discount discount = new Discount(0.0, "");
 		boolean ruleResult = CONDITION_GROUP_LOGIC_OPERATOR.AND.equals(this.operator) ? true : false;
 
 		if (conditions.length > 0) {
-			for (Condition condition: conditions) {
+			for (Condition condition : conditions) {
 				boolean runCondition = condition.runCondition(product);
 				ruleResult = CONDITION_GROUP_LOGIC_OPERATOR.AND.equals(this.operator) ? runCondition && ruleResult
 						: ruleResult || runCondition;
@@ -59,8 +66,7 @@ public Discount applyDiscountRule(Product product) throws AmazingKartException {
 
 		return discount;
 	}
-
-
+
 	public DISCOUNT_TYPE getDiscount_type() {
 		return discount_type;
 	}
@@ -85,7 +91,6 @@ public void setDiscountTag(String discountTag) {
 		this.discountTag = discountTag;
 	}
 
-
 	public CONDITION_GROUP_LOGIC_OPERATOR getOperator() {
 		return operator;
 	}
@@ -110,6 +115,4 @@ public void setGroup_LOGIC_OPERATOR(CONDITION_GROUP_LOGIC_OPERATOR group_LOGIC_O
 		this.group_LOGIC_OPERATOR = group_LOGIC_OPERATOR;
 	}
 
-
-
 }

amazingkart/src/main/java/com/amazingkart/promotions/PromotionA.java

@@ -6,6 +6,7 @@
 
 public class PromotionA extends PromotionSet {
 
+	/*List of promotion rules for set A*/
 	DiscountRule[] discountRules = {
 			new DiscountRule(DISCOUNT_TYPE.PERCENTAGE, 7.0, "get 7% off", CONDITION_GROUP_LOGIC_OPERATOR.OR,
 					new Condition[] { new Condition("origin", COMPARISON_OPERATOR.EQUAL, new String[] { "Africa" }) }),

amazingkart/src/main/java/com/amazingkart/promotions/PromotionB.java

@@ -5,6 +5,7 @@
 
 public class PromotionB extends PromotionSet {
 
+	/*List of promotion rules for set B*/
 	DiscountRule[] rules = {
 			new DiscountRule(DISCOUNT_TYPE.PERCENTAGE, 12.0, "get 12% off", CONDITION_GROUP_LOGIC_OPERATOR.OR,
 					new Condition[] { new Condition("inventory", Condition.COMPARISON_OPERATOR.GREATER_THAN,