public class Classroom { // fields private String roomNumber; private String buildingName; private int capacity; /**...

public class Classroom
{
// fields
private String roomNumber;
private String buildingName;
private int capacity;

/**
* Constructor for objects of class Classroom
*/
public Classroom()
{
this.capacity = 0;
}

/**
* Constructor for objects of class Classroom
*
* @param rN the room number
* @param bN the building name
* @param c the room capacity
*/
public Classroom(String rN, String bN, int c)
{
setRoomNumber(rN);
setBuildingName(bN);
setCapacity(c);
}

/**
* Mutator method (setter) for room number.
*
* @param rN a new room number
*/
public void setRoomNumber(String rN)
{
this.roomNumber = rN;
}

/**
* Mutator method (setter) for building name.
*
* @param bN a new building name
*/
public void setBuildingName(String bN)
{
this.buildingName = bN;
}

/**
* Mutator method (setter) for capacity.
*
* @param c a new capacity
*/
public void setCapacity(int c)
{
this.capacity = c;
}

/**
* Accessor method (getter) for room number.
*
* @return the room number
*/
public String getRoomNumber()
{
return this.roomNumber;
}

/**
* Accessor method (getter) for building name.
*
* @return the building name
*/
public String getBuildingName()
{
return this.buildingName;
}

/**
* Accessor method (getter) for capacity.
*
* @return the capacity
*/
public int getCapacity()
{
return this.capacity;
}
}

Modify this class so that it implements the Comparable interface. This will involve adding a method called compareTo() to your Room class and making some other changes to the class definition.
Now write a main program (in a new class called TestComparable) that creates an ArrayList of Rooms. Add about 5 Rooms to the list so that they're randomly ordered. Print the list in its current order. Then call the sort() method to sort the Rooms based on capacity. Print the list in the new sorted order.

Expert Solution

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

CODE TO COPY

public class Classroom implements Comparable<Classroom> {
// fields
   private String roomNumber;
   private String buildingName;
   private int capacity;

   /**
   * Constructor for objects of class Classroom
   */
   public Classroom() {
       this.capacity = 0;
   }

   /**
   * Constructor for objects of class Classroom
   *
   * @param rN the room number
   * @param bN the building name
   * @param c the room capacity
   */
   public Classroom(String rN, String bN, int c) {
       setRoomNumber(rN);
       setBuildingName(bN);
       setCapacity(c);
   }

   /**
   * Mutator method (setter) for room number.
   *
   * @param rN a new room number
   */
   public void setRoomNumber(String rN) {
       this.roomNumber = rN;
   }

   /**
   * Mutator method (setter) for building name.
   *
   * @param bN a new building name
   */
   public void setBuildingName(String bN) {
       this.buildingName = bN;
   }

   /**
   * Mutator method (setter) for capacity.
   *
   * @param c a new capacity
   */
   public void setCapacity(int c) {
       this.capacity = c;
   }

   /**
   * Accessor method (getter) for room number.
   *
   * @return the room number
   */
   public String getRoomNumber() {
       return this.roomNumber;
   }

   /**
   * Accessor method (getter) for building name.
   *
   * @return the building name
   */
   public String getBuildingName() {
       return this.buildingName;
   }

   /**
   * Accessor method (getter) for capacity.
   *
   * @return the capacity
   */
   public int getCapacity() {
       return this.capacity;
   }

   @Override
   public int compareTo(Classroom o) {
       return Integer.compare(getCapacity(), o.getCapacity());
   }
}

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

TestComparable.java

import java.util.ArrayList;
import java.util.Comparator;

public class TestComparable {

   public static void main(String[] args) {
       ArrayList<Classroom> ar = new ArrayList<Classroom>();
       ar.add(new Classroom("r1", "b1", 10));
       ar.add(new Classroom("r2", "b2", 40));
       ar.add(new Classroom("r3", "b3", 50));
       ar.add(new Classroom("r4", "b4", 20));
       ar.add(new Classroom("r5", "b5", 5));

       System.out.println("Before Sorting");
       for (int j = 0; j < ar.size(); j++) {
           System.out.println(ar.get(j).getRoomNumber()+" : "+ar.get(j).getCapacity());
       }

       ar.sort(Comparator.comparing(Classroom::getCapacity));

       System.out.println("\nAfter Sorting");
       for (int j = 0; j < ar.size(); j++) {
           System.out.println(ar.get(j).getRoomNumber()+" : "+ar.get(j).getCapacity());
       }
   }
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

EXPLANATION

CODE TO COPY

public class Classroom implements Comparable<Classroom> { // IMPLEMENTING COMPARABLE INTERFACE

// SINCE WE ARE IMPLEMENTING THIS METHOD WE HAVE TO ADD A COMPARETO METHOD
// fields
   private String roomNumber;
   private String buildingName;
   private int capacity;