Question

Please help me to solve this source code.

Use the following file:

InterfaceRunner.java

import java.util.ArrayList;
public class InterfaceRunner
{
   public static void main(String[] args)
   {
       ArrayList<GeometricSolid> shapes = new ArrayList<>();
       shapes.add(new Sphere(10));
       shapes.add(new Sphere(1));
       shapes.add(new Cylinder(1, 5));
       shapes.add(new Cylinder(10, 20));
       shapes.add(new RightCircularCone(1, 5));
       shapes.add(new RightCircularCone(10, 20));
       
       /*
        * Notice that the array list holds different kinds of objects
        * but each one is a GeometricSolid because it implements
        * the interface.
        * 
        */
       for (GeometricSolid shape : shapes)
       {
           System.out.printf("%.2f%n",shape.volume());
       }
   }
}

Here is the instruction

Writing an Interface

In this problem you will first write an interface and then modify classes to implement the interface. Write an interface, GeometricSolid, which has one method, volume. The volume method takes no arguments and returns a double.

You are provided with three classes: Cylinder, Sphere, and RightCircularCone Modify the classes so that they implement the GeometricSolid interface. Supply the appropriate method for each class. You can use Google search to find the formula for the volume. Make sure that you use Math.PI in your calculations.

Notice in InterfaceRunner that the objects are added to an ArrayList of GeometricSolids.

Here are the source codes provided:

Cylinder.java

/**
* Models a Cylinder
*/
public class Cylinder
{
private double radius;
private double height;

/**
* Constructor for objects of class Cylinder
* @param radius the radius of the Cylinder
* @param height the height of this Cylinder
*/
public Cylinder(double radius, double height)
{
this.radius = radius;
this.height = height;
}
  
/**
* Gets the radius of this Cylinder
* @return the radius of the Cylinder
*/
public double getRadius()
{
return radius;
}
  
/**
* Sets the radius of the Cylinder
* @param newRadius the value of the new radius
*/
public void setRadius(int newRadius)
{
radius = newRadius;
}
  
/**
* Gets the height of this Cylinder
* @return the height of the Cylinder
*/
public double getHeight()
{
return height;
}
  
/**
* Sets the height of the Cylinder
* @param newHeight the value of the new height
*/
public void setHeight(int newHeight)
{
height = newHeight;
}
}

RightCircularCone.java

/**

* Models a Right circular cone

*/
public class RightCircularCone

{
private double radius;
private double height;

/**
* Constructor for objects of class RightCircularCone
* @param radius the radius of the RightCircularCone
* @param height the height of this RightCircularCone
*/
public RightCircularCone(double radius, double height)
{
this.radius = radius;
this.height = height;
}
  
/**
* Gets the radius of this RightCircularCone
* @return the radius of the RightCircularCone
*/
public double getRadius()
{
return radius;
}
  
/**
* Sets the radius of the RightCircularCone
* @param newRadius the value of the new radius
*/
public void setRadius(double newRadius)
{
radius = newRadius;
}
  
/**
* Gets the height of this RightCircularCone
* @return the height of the RightCircularCone
*/
public double getHeight()
{
return height;
}
  
/**
* Sets the height of the RightCircularCone
* @param newHeight the value of the new height
*/
public void setHeight(double newHeight)
{
height = newHeight;
}
}

Sphere.java

/**
* Models a sphere in 3-d space
*/
public class Sphere
{
private double radius;  

/**
* Constructor for objects of class Sphere
* @param radius the radius of this Sphere
*/
public Sphere(double radius)
{
this.radius = radius;
}
  
/**
* Gets the radius of this Sphere
* @return the radius of this Sphere
*/
public double getRadius()
{
return radius;
}
  
/**
* Sets the the radius of this Sphere
* @param newRadius the radius of this Sphere
*/
public void setRadius(double newRadius)
{
radius = newRadius;
}

}

Here is the source code needed to complete:

GeometricSolid.java

Answer 1

1. We have 3 classes and 1 interface. In total, 4 java files to be saved in 4 different files with extension .java but in same folder. Because we do not use separate packages.

2. After saving all the files, just compile and run the java file that contains the main method i.e., InterfaceRunner.java file.

GeometricSolid.java

public interface GeometricSolid {
  
/* By default the methods in interface are 'public and abstract',

so needed to be implemented by the class that implement this interface. */

double volume();

}

Cylinder.java

public class Cylinder implements GeometricSolid{
  
   /**
   * Models a Cylinder
   */
   private double radius;
   private double height;

   /**
   * Constructor for objects of class Cylinder
   * @param radius the radius of the Cylinder
   * @param height the height of this Cylinder
   */
   public Cylinder(double radius, double height)
   {
   this.radius = radius;
   this.height = height;
   }
  
   /**
   * Gets the radius of this Cylinder
   * @return the radius of the Cylinder
   */
   public double getRadius()
   {
   return radius;
   }
  
   /**
   * Sets the radius of the Cylinder
   * @param newRadius the value of the new radius
   */
   public void setRadius(int newRadius)
   {
   radius = newRadius;
   }
  
   /**
   * Gets the height of this Cylinder
   * @return the height of the Cylinder
   */
   public double getHeight()
   {
   return height;
   }
  
   /**
   * Sets the height of the Cylinder
   * @param newHeight the value of the new height
   */
   public void setHeight(int newHeight)
   {
   height = newHeight;
   }

   @Override // Interface method implemented
   public double volume() {
                return Math.PI*radius*radius*height;
   }

}

Sphere.java

/**
* Models a sphere in 3-d space
*/
public class Sphere implements GeometricSolid
{
private double radius;

/**
* Constructor for objects of class Sphere
* @param radius the radius of this Sphere
*/
public Sphere(double radius)
{
this.radius = radius;
}

/**
* Gets the radius of this Sphere
* @return the radius of this Sphere
*/
public double getRadius()
{
return radius;
}

/**
* Sets the the radius of this Sphere
* @param newRadius the radius of this Sphere
*/
public void setRadius(double newRadius)
{
radius = newRadius;
}

@Override    // Interface method implemented
public double volume() {
   return (4*Math.PI*Math.pow(radius, 3))/3;
}

}

RightCircularCone.java

/**

* Models a Right circular cone

*/
public class RightCircularCone implements GeometricSolid

{
private double radius;
private double height;

/**
* Constructor for objects of class RightCircularCone
* @param radius the radius of the RightCircularCone
* @param height the height of this RightCircularCone
*/
public RightCircularCone(double radius, double height)
{
this.radius = radius;
this.height = height;
}

/**
* Gets the radius of this RightCircularCone
* @return the radius of the RightCircularCone
*/
public double getRadius()
{
return radius;
}

/**
* Sets the radius of the RightCircularCone
* @param newRadius the value of the new radius
*/
public void setRadius(double newRadius)
{
radius = newRadius;
}

/**
* Gets the height of this RightCircularCone
* @return the height of the RightCircularCone
*/
public double getHeight()
{
return height;
}

/**
* Sets the height of the RightCircularCone
* @param newHeight the value of the new height
*/
public void setHeight(double newHeight)
{
height = newHeight;
}

@Override   // INterface method implemented
public double volume() {
   return Math.PI*radius*radius*(height/3);
}

}

InterfaceRunner.java

import java.util.ArrayList;
public class InterfaceRunner
{
   public static void main(String[] args)
   {
       ArrayList<GeometricSolid> shapes = new ArrayList<>();
       shapes.add(new Sphere(10));
       shapes.add(new Sphere(1));
       shapes.add(new Cylinder(1, 5));
       shapes.add(new Cylinder(10, 20));
       shapes.add(new RightCircularCone(1, 5));
       shapes.add(new RightCircularCone(10, 20));
     
       /*
        * Notice that the array list holds different kinds of objects
        * but each one is a GeometricSolid because it implements
        * the interface.
        *
        */
       for (GeometricSolid shape : shapes)
       {
           System.out.printf("%.2f%n",shape.volume());
       }
   }
}

OUTPUT

4188.79
4.19
15.71
6283.19
5.24
2094.40