Question

Need a help with this one

FoodListInterface.java specifies a Java interface for an ADT that maintains a list of foods, dishes or meals. This interface includes two operations: add(String food) – add the name of a food, dish or meal to the list onTheMenu(String food) – check if a given food item is on the list Develop three implementations of this interface, each with a different underlying data structure: Array Linked list ArrayList from the java.util package (a Java Collections Framework class) Each implementation is a separate class, and each of these classes is to include a toString() method to list out the food items, one per line. The source code for the interface is provided in the foodList package in the attached Eclipse project export file for this assignment. The linked list implementation must use the LLStringNode.java class provided in the foodList package; do not use the LinkedList class from the java.util package. To earn full credit you must make use of appropriate ArrayList methods to efficiently develop the food list ADT based on that data structure, along with an enhanced for loop to traverse the list of foods for the toString() method. In addition to the three ADT classes, create a single Java program – i.e., a Java class with a main() method – to test each of the implementations. For each implementation: Instantiate a list object and add seven of your favorite things to eat; Using System.out.println(), display the list of food items; Use the onThisList() method to test whether fettuccine alfredo is on your list, and report out the result; and Use the onThisList() method to test another food, and report out that result – make sure to use a food, dish or meal that produces the opposite result from the first test. Submit the following items:

Answer 1

Answer:

// FoodListInterface.java

/**

* interface to represent a system to store a list of food and check if a given

* food is present on the list

*/

public interface FoodListInterface {

              public void add(String food); // add the name of a food, dish or meal to the

                                                                                                                           // list

              public boolean onTheMenu(String food); // check if a given food item is on

                                                                                                                                                      // the list

}

// FoodListArray.java

/**

* implementation of FoodListInterface using an Array as underlying data

* structure

*/

public class FoodListArray implements FoodListInterface {

              // array to store foods

              private String foods[];

              // current number of foods in the array

              private int count;

              // default constructor, initializes empty food list

              public FoodListArray() {

                           // using default initial capacity of array

                           foods = new String[10];

                           // setting current number of foods to 0

                           count = 0;

              }

              @Override

              public void add(String food) {

                           // if array is full,doubling its size

                           if (count == foods.length) {

                                         // creating a new array of double capacity, copying all elements and

                                         // replacing old array

                                         String newArray[] = new String[count * 2];

                                         System.arraycopy(foods, 0, newArray, 0, count);

                                         foods = newArray;

                           }

                           // adding to end

                           foods[count] = food;

                           count++;

              }

              @Override

              public boolean onTheMenu(String food) {

                           // looping through array and checking if any object matches the given

                           // food

                           for (int i = 0; i < count; i++) {

                                         if (foods[i].equalsIgnoreCase(food)) {

                                                       // found

                                                       return true;

                                         }

                           }

                           // not found

                           return false;

              }

              @Override

              public String toString() {

                           String str = "[";

                           // appending all food data to a String variable enclosed within square

                           // braces

                           for (int i = 0; i < count; i++) {

                                         str += foods[i];

                                         if (i != count - 1) {

                                                       str += ", ";

                                         }

                           }

                           str += "]";

                           return str;

              }

}

// FoodListArrayList.java

import java.util.ArrayList;

/**

* implementation of FoodListInterface using an ArrayList as underlying data

* structure

*/

public class FoodListArrayList implements FoodListInterface {

              //array list of String to represent foods

              private ArrayList<String> foods;

              // default constructor, initializes empty food list

              public FoodListArrayList() {

                           //initializing array list

                           foods = new ArrayList<String>();

              }

              @Override

              public void add(String food) {

                           // using ArrayList's built in method to add to foods list

                           foods.add(food);

              }

              @Override

              public boolean onTheMenu(String food) {

                           // using ArrayList's built in method to check if it contains a String

                           // with given value

                           return foods.contains(food);

              }

              @Override

              public String toString() {

                           // calling array list's built in implementation of toString

                           return foods.toString();

              }

}

// FoodListLinkedList.java

/**

* implementation of FoodListInterface using a linked list as underlying data

* structure

*/

public class FoodListLinkedList implements FoodListInterface {

              private LLStringNode head;

              // default constructor, initializes empty food list

              public FoodListLinkedList() {

                           head = null;

              }

              @Override

              public void add(String food) {

                           //updating head node if it is null

                           if (head == null) {

                                         head = new LLStringNode(food);

                           } else {

                                         //finding the last node

                                         LLStringNode temp = head;

                                         while (temp.getLink() != null) {

                                                       temp = temp.getLink();

                                         }

                                         //adding next to last node

                                         temp.setLink(new LLStringNode(food));

                           }

              }

              @Override

              public boolean onTheMenu(String food) {

                           LLStringNode temp = head;

                           while (temp != null) {

                                         if (temp.getInfo().equalsIgnoreCase(food)) {

                                                       return true;

                                         }

                                         temp = temp.getLink();

                           }

                           return false;

              }

              @Override

              public String toString() {

                           // appending all food data to a String variable enclosed within square

                           // braces

                           String str = "[";

                           LLStringNode temp = head;

                           while (temp != null) {

                                         str += temp.getInfo();

                                         temp = temp.getLink();

                                         if (temp != null) {

                                                       str += ", ";

                                         }

                           }

                           str += "]";

                           return str;

              }

}

//Assuming you have LLStringNode class with you.

// Test.java

/**

* class for testing all three implementations of FoodListInterface

*/

public class Test {

              public static void main(String[] args) {

                           //testing each implementation separately, using same inputs

                           System.out.println("Testing FoodListArray\n");

                           FoodListArray array = new FoodListArray();

                           array.add("Pizza");

                           array.add("Paratha");

                           array.add("Barbecue");

                           array.add("Burger");

                           array.add("Sandwich");

                           array.add("Shawarma");

                           array.add("Big Belly Burger");

                           System.out.println(array);

                           System.out.println("Is fettuccine alfredo on food list? "

                                                       + array.onTheMenu("fettuccine alfredo"));

                           System.out.println("Is Big Belly Burger on food list? "

                                                       + array.onTheMenu("Big Belly Burger"));

                          

                           System.out.println("\nTesting FoodListLinkedList\n");

                           FoodListArray linkedList = new FoodListArray();

                           linkedList.add("Pizza");

                           linkedList.add("Paratha");

                           linkedList.add("Barbecue");

                           linkedList.add("Burger");

                           linkedList.add("Sandwich");

                           linkedList.add("Shawarma");

                           linkedList.add("Big Belly Burger");

                           System.out.println(linkedList);

                           System.out.println("Is fettuccine alfredo on food list? "

                                                       + linkedList.onTheMenu("fettuccine alfredo"));

                           System.out.println("Is Big Belly Burger on food list? "

                                                       + linkedList.onTheMenu("Big Belly Burger"));

                          

                           System.out.println("\nTesting FoodListArrayList\n");

                           FoodListArray arrayList = new FoodListArray();

                           arrayList.add("Pizza");

                            arrayList.add("Paratha");

                           arrayList.add("Barbecue");

                           arrayList.add("Burger");

                           arrayList.add("Sandwich");

                           arrayList.add("Shawarma");

                           arrayList.add("Big Belly Burger");

                           System.out.println(arrayList);

                           System.out.println("Is fettuccine alfredo on food list? "

                                                       + arrayList.onTheMenu("fettuccine alfredo"));

                           System.out.println("Is Big Belly Burger on food list? "

                                                       + arrayList.onTheMenu("Big Belly Burger"));

                          

              }

}

/*OUTPUT*/

Testing FoodListArray

[Pizza, Paratha, Barbecue, Burger, Sandwich, Shawarma, Big Belly Burger]

Is fettuccine alfredo on food list? false

Is Big Belly Burger on food list? true

Testing FoodListLinkedList

[Pizza, Paratha, Barbecue, Burger, Sandwich, Shawarma, Big Belly Burger]

Is fettuccine alfredo on food list? false

Is Big Belly Burger on food list? true

Testing FoodListArrayList

[Pizza, Paratha, Barbecue, Burger, Sandwich, Shawarma, Big Belly Burger]

Is fettuccine alfredo on food list? false

Is Big Belly Burger on food list? true