Question

JAVA

The following is about creating a class Ruler and testing it.

​​(i) Create a class Ruler with the attributes brand (which is a string) and length (an integer) which are used to store the brand and length of the ruler respectively. Write a constructor Ruler(String brand, int length) which assigns the brand and length appropriately. Write also the getter/setter methods of the two attributes. Save the content under an appropriate file name. Copy the content of the file as the answers to this part.

(ii) Create another class TestRuler in a separate file with a method main() to test the class Ruler. In main(), create a Ruler object aRuler with brand "Brand A" and length 30. Print the message "A Ruler object has been created: brand is Brand A, length is 30", in which the data "Brand A" and "30" are obtained from the corresponding getter method of the attribute. Run the program. Copy the content of the file and the output showing the message as the answers to this part.

(iii) Create the class StationeryShop which contains an attribute ruler which is a Ruler array. In the constructor StationeryShop(Ruler[] ruler), initialize the attribute ruler using the parameter. Also write the getter/setter method of the attribute ruler. Copy the content of the file as the answers to this part.

(iv) Write a method displayRuler(int index) of the class StationeryShop to produce output similar to the following:

      Ruler number 2
       brand : Brand A
       length : 30

where Brand A is the brand and 30 is the length of ruler, and index has the value 2. The parameter index is the index of the array ruler. Copy the content of the method as the answers to this part.

(v) Add a method brandCount(String aBrand) to the class StationeryShop which returns the number of rulers with brand aBrand. Copy the content of the method as the answers to this part.

(vi) Add another method longRulers() to the class StationeryShop which returns an array with 2 elements containing Ruler objects with longest and second longest lengths, which are assumed to be unique. Copy the content of the method as the answers to this part.

(vii) Create another class TestStationeryShop in a separate file with a method main() to perform the following:

1. create a StationeryShop object myStationeryShop and initialize it with data for 3 rulers: ("Brand A", 30), ("Brand B", 20), ("Brand C", 60);

2. display the ruler with index 2 using displayRuler();

3. print the number of rulers with brand "Brand A";

4. print the brand and length of the rulers with top 2 lengths;

Answer 1

Ruler.java

public class Ruler {
   //member variables
   private String brand;
   private int length;
  
   //constructor
   public Ruler(String brand, int length)
   {
       this.brand = brand;
       this.length = length;
   }
  
   //setters
   //method that sets brand
   public void setBrand(String brand)
   {
       this.brand = brand;
   }
  
   //method that sets length
   public void setLength(int length)
   {
       this.length = length;
   }
  
   //getters
   //method that gets brand
   public String getBrand()
   {
       return this.brand;
   }
  
   //method that gets length
   public int getLength()
   {
       return this.length;
   }
}

TestRuler.java

public class TestRuler {

   public static void main(String[] args) {
       //create a Ruler object with Brand A and length 30
       Ruler aRuler = new Ruler("Brand A", 30);
       //display ruler info
       System.out.println("A Ruler object has been created: brand is " + aRuler.getBrand() + ", length is " + aRuler.getLength());

   }

}

Output:

Code Screenshot:

StationeryShop.java

public class StationeryShop {
   //attribute
   private Ruler[] ruler;
  
   //constructor
   public StationeryShop(Ruler[] ruler)
   {
       this.ruler = ruler;
   }
  
   //method that sets the ruler array
   public void setRuler(Ruler[] ruler)
   {
       this.ruler = ruler;
   }
  
   //method that returns the ruler array
   public Ruler[] getRuler()
   {
       return this.ruler;
   }
  
   //method that displays the ruler info at specified index
   public void displayRuler(int index)
   {
       System.out.println("Ruler number " + index);
       System.out.println("brand: " + ruler[index].getBrand());
       System.out.println("length: " + ruler[index].getLength());
   }
  
   //method that return number of brands with given brand
   public int brandCount(String aBrand)
   {
       int count = 0;
       //iterate through the ruler array
       for(int i = 0; i < ruler.length; i++)
       {
           //compare and increment count if match found
           if(ruler[i].getBrand().equalsIgnoreCase(aBrand))
               count++;
       }
       return count;
   }
  
   //method that returns array of two long rulers
   public Ruler[] longRulers()
   {
       Ruler[] lngRulers = new Ruler[2];
       Ruler temp;
       //iterate through the rulers array
       for (int i = 1; i < this.ruler.length; i++)
       {
           for (int j = i; j > 0; j--)
           {
               //sort the rulers array based on length
               if (ruler[j].getLength() > ruler [j - 1].getLength())
               {
                   temp = ruler[j];
                   ruler[j] = ruler[j - 1];
                   ruler[j - 1] = temp;
               }
           }
       }  
       //store the top 2 lengths in the array
       lngRulers[0] = ruler[0];
       lngRulers[1] = ruler[1];
       return lngRulers;
   }
}

TestStationeryShop.java

public class TestStationaryShop {
   public static void main(String[] args) {
       //create an object to StationeryShop with 3 rulers
       Ruler[] ruler = new Ruler[3];
       ruler[0] = new Ruler("Brand A", 30);
       ruler[1] = new Ruler("Brand B", 20);
       ruler[2] = new Ruler("Brand C", 60);
      
       StationeryShop myStationeryShop = new StationeryShop(ruler);
      
       //display ruler at index 2
       myStationeryShop.displayRuler(2);
      
       //print the number of rulers with Brand A
       System.out.println("\nNumber of rulers with Brand A: " + myStationeryShop.brandCount("Brand A"));
      
       //print the brand and length with 2 top lengths
       Ruler[] longRulers = myStationeryShop.longRulers();
       System.out.println("\nRulers with top 2 lengths: ");
       //display the brand and length of top 2 lengths
       for(int i = 0; i < longRulers.length; i++)
       {
           System.out.println("brand: " + longRulers[i].getBrand() + " length: " + longRulers[i].getLength());
       }
   }
}

Output:

Code screenshot: