Question

The purpose of this homework is to practice OOP programming covering Inheritance in java.

The scenario is to design an online shopping system for a local supermarket (e.g., Europa Foods Supermarket or Wang Long Oriental Supermarket) and is mostly concentrated on the product registration system.

Design and draw a UML diagram, and write the code for the following classes:

• ID: The identification number must start with 1 and follows with 6 numbers, e.g., “1123456”.

• Description, e.g. “Banana”

• Recommended Price per unit, e.g. 5.54. Note that this is the suggested price, it is not the actual price

  in the online shopping system.

• Unit (by default is 1)

• Weight (in gram)

• Unit Type, e.g. “Each, Kilogram, Bunch, Box and Pack”

• The packing or baking date (it should include the date, month, year and time), this information is not

  required for some product, hence, it default may be set to 1/1/1900.

• The expiry date is (it should include the date, month, year)

0. The purpose of this class is to maintain the general information of fresh or daily product such as meat, seafood, bread, milk and vegetable.

1. The second product category is a packaged product such as can, source, snack, etc. It contains the following attributes.

• ID: The identification number must start with 2 and follows with 6 numbers, e.g., “2123456”.

• Description, e.g. “Corn cream can”

• Recommended Price per unit, e.g. 5.54.

• Unit (by default is 1)

• Weight (in gram)

• The dimension of the package (including height, width, deep). If a product doesn’t provide this

  information, then it set to (0, 0, 0) as a default value.

• Nutrition Information

• o Quantityper100gor100ml

• o Energy/kilojoules

• o Protein

• o Fat

• o Sugars(mg)

• o Sodium/salt(mg)

• Unit Type for this class is limited to only “Box, Bottle and Pack”

• Packing or manufacturing date (it should include the date, month, year and time), this information is

  not required for some product, hence, it default may be set to 1/1/1900.

• Expire date is (it should include the date, month, year), its default may be set to 1/1/3000 for the

  product that doesn’t have an expiry date.

0. The purpose of this class is to maintain the general information of package product such as can, sauce, instant noodle, flour and snack.

1. Noted that all classes should override and implement the toString methods to transform the information of the object into the string variable.

2. Ensure that all classes are well designed with practical attributes (either primitive type, class object or Enumerated Data type) and have proper methods to handle all tasks (Encapsulation).

3. Task 1: Class design (Code and UML).

1. Design and write the java code for the above two categories.

2. Design 2 subclass with 2 additional attributes for each category.

0. Task 2: Your classes should be able to provide methods allowing one to

1. (verifyUnitType) Check whether the input arguments (a unit type) passed to the method matches with

   the user type stored in the object or not.

2. (getAttributeDescriptionForSavingTofile) output the description of all attributes to a String format

   that can be used to save it to a CVS format file directly, e.g. “ID, Description, .... , Expire date”.

3. (getInformationForSavingToFile) Take all attributes in the object and output them to a String format

   that can be used to save it to a CVS format file directly, e.g. “1222344, Corn Cream,.... ,

   20/11/2019”.

4. Choose the appropriate input or/and output type for each method.

5. Test Code: write the test code (a separate class/file called “TestCode” with the Main method in it), create the object of each class, and create an ArrayList to keep all the above classes. For each object, call methods in Task 2 to check whether the method works properly. Display the output of the methods to the console. Finally, display information of all the object in the ArrayList to the console.

Answer 1

package inheritance;

import java.util.*;

// Defines super class Product

class Product

{

// Instance variable to store product information

String id;

String description;

double price;

double weight;

Date packingDate;

Date expiryDate;

// Default constructor to assign default values to instance variables

@SuppressWarnings("deprecation")

Product()

{

id = description = "";

price = weight = 0.0;

packingDate.setDate(1);

packingDate.setMonth(1);

packingDate.setYear(1900);

expiryDate.setDate(0);

expiryDate.setMonth(0);

expiryDate.setYear(0);

}// End of default constructor

// Parameterized constructor to assign parameter values to instance variables

Product(String ID, String des, double pr, double we, Date pd, Date ex)

{

id = ID;

description = des;

price = pr;

weight = we;

packingDate = pd;

expiryDate = ex;

}// End of parameterized constructor

// Method to set id

void setId(String ID)

{

id = ID;

}// End of method

// Method to set price

void setPrice(double pr)

{

price = pr;

}// End of method

// Method to set weight

void setWeight(double we)

{

weight = we;

}// End of method

// Method to set packing date

void setPackingDate(Date pd)

{

packingDate = pd;

}// End of method

// Method to set expiry date

void setExpiryDate(Date ed)

{

expiryDate = ed;

}// End of method

// Method to return id

String getId()

{

return id;

}// End of method

// Method to return price

double getPrice()

{

return price;

}// End of method

// Method to return weight

double getWeight()

{

return weight;

}// End of method

// Method to return packing date

Date getPackingDate()

{

return packingDate;

}// End of method

// Method to return expiry date

Date getExpiryDate()

{

return expiryDate;

}// End of method

// Overrides toString method to return product information

public String toString()

{

return "\n\n Product Id: " + id + "\n Price: " + price +

"\n Weight: " + weight + "\n Packing Date: " + packingDate +

"\n Expiry Date: " + expiryDate;

}// End of method

}// End of class Product

// Derived a class DailyProduct from super class Product

class DailyProduct extends Product

{

// Instance variable to store daily product information

String unitType;

// Default constructor to assign default values to instance variables

DailyProduct()

{

// Calls the base class constructor

super();

unitType = "";

}// End of default constructor

// Parameterized constructor to assign parameter values to instance variables

DailyProduct(String ID, String des, double pr, double we,

Date pd, Date ex, String ut)

{

// Calls the base class constructor

super(ID, des, pr, we, pd, ex);

unitType = ut;

}// End of parameterized constructor

// Method to set unit type

void setUnitType(String ut)

{

unitType = ut;

}// End of method

// Method to return unit type

String getUnitType()

{

return unitType;

}// End of method

// Overrides toString method to return daily product information

public String toString()

{

return super.toString() + "\n Unit Type: " + unitType;

}// End of method

}// End of class DailyProduct

// Derived a class PackageProduct from super class Product

class PackageProduct extends Product

{

// Instance variable to store package product information

int packageWdith;

int packageHeight;

int packageDeep;

String unitType;

String nutritionInfo;

// Default constructor to assign default values to instance variables

PackageProduct()

{

// Calls the base class constructor

super();

packageWdith = packageHeight = packageDeep = 0;

unitType = nutritionInfo = "";

}// End of default constructor

// Parameterized constructor to assign parameter values to instance variables

PackageProduct(String ID, String des, double pr, double we,

Date pd, Date ex, int pw, int ph, int pde, String ut, String ni)

{

// Calls the base class constructor

super(ID, des, pr, we, pd, ex);

packageWdith = pw;

packageHeight = ph;

packageDeep = pde;

unitType = ut;

nutritionInfo = ni;

}// End of parameterized constructor

// Method to set width

void setPackageWdith(int pw)

{

packageWdith = pw;

}// End of method

// Method to set height

void setPackageHeight(int ph)

{

packageHeight = ph;

}// End of method

// Method to set depth

void setPackageDeep(int pd)

{

packageDeep = pd;

}// End of method

// Method to set unit type

void setUnitType(String ut)

{

unitType = ut;

}// End of method

// Method to set nutrition

void setNutritionInfo(String ni)

{

nutritionInfo = ni;

}// End of method

// Method to return width

int getPackageWdith()

{

return packageWdith;

}// End of method

// Method to return height

int getPackageHeight()

{

return packageHeight;

}// End of method

// Method to return depth

int getPackageDeep()

{

return packageDeep;

}// End of method

// Method to return unit type

String getUnitType()

{

return unitType;

}// End of method

// Method to return nutrition

String getNutritionInfo()

{

return nutritionInfo;

}// End of method

// Overrides toString method to return packing product information

public String toString()

{

return super.toString() + "\n Packing Width: " + packageWdith +

"\n Packing Height: " + packageHeight +

"\n Packing Deepth: " + packageDeep +

"\n Unit Type: " + unitType + "\n Nutrition: " + nutritionInfo;

}// End of method

}// End of class PackageProduct

// Defines driver class FoodsSupermarket

public class FoodsSupermarket

{

// main method definition

@SuppressWarnings("deprecation")

public static void main(String st[])

{

// Declares an array list to store products

ArrayList Product = new ArrayList();

// Declares an array of objects for DailyProduct

DailyProduct dp[] = new DailyProduct[3];

// Declares an array of objects for PackageProduct

PackageProduct pp[] = new PackageProduct[3];

// Creates daily product using parameterized constructor

dp[0] = new DailyProduct("1123456", "Banana", 2.56, 1.2, new Date(1, 1, 1998),

new Date(5,1,198), "Each");

dp[1] = new DailyProduct("1123458", "Orange", 89.36, 22.23,

new Date(1, 3, 1999), new Date(5,3,198), "Kilogram");

// Creates package product using parameterized constructor

pp[0] = new PackageProduct("2123477", "noodle", 2.56, 1.2,

new Date(1, 1, 1998), new Date(5,1,198), 12, 10, 5, "Each", "Protein");

pp[1] = new PackageProduct("2123488", "snack", 45.44, 31.11,

new Date(1, 1, 1998), new Date(5,1,198), 22, 12, 3, "Box", "Sodium");

// Adds the daily product objects

Product.add(dp[0]);

Product.add(dp[1]);

// Adds the package product objects

Product.add(pp[0]);

Product.add(pp[1]);

// Loops to display all product information

for(int c = 0; c < Product.size(); c++)

System.out.println(Product.get(c));

}// End of main method

}// End of driver class FoodsSupermarket

Sample Output:

Product Id: 1123456
Price: 2.56
Weight: 1.2
Packing Date: Sun Jul 22 00:00:00 IST 1906
Expiry Date: Thu Aug 17 00:00:00 IST 1905
Unit Type: Each

Product Id: 1123458
Price: 89.36
Weight: 22.23
Packing Date: Thu Sep 20 00:00:00 IST 1906
Expiry Date: Sun Oct 15 00:00:00 IST 1905
Unit Type: Kilogram

Product Id: 2123477
Price: 2.56
Weight: 1.2
Packing Date: Sun Jul 22 00:00:00 IST 1906
Expiry Date: Thu Aug 17 00:00:00 IST 1905
Packing Width: 12
Packing Height: 10
Packing Deepth: 5
Unit Type: Each
Nutrition: Protein

Product Id: 2123488
Price: 45.44
Weight: 31.11
Packing Date: Sun Jul 22 00:00:00 IST 1906
Expiry Date: Thu Aug 17 00:00:00 IST 1905
Packing Width: 22
Packing Height: 12
Packing Deepth: 3
Unit Type: Box
Nutrition: Sodium