OOAD 2017 old paper Solution

Group C

Q.no 8

Step 1

public interface Shape {
   void draw();
}

public interface Shape {

void draw();

}

Create an interface.
Shape.java

Step 2

Create concrete classes implementing the same interface.
Rectangle.java

<span class="kwd">public</span> <span class="kwd">class</span> <span class="typ">Rectangle</span> <span class="kwd">implements</span> <span class="typ">Shape</span> <span class="pun">{</span>
   <span class="lit">@Override</span>
   <span class="kwd">public</span> <span class="kwd">void</span><span class="pln"> draw</span><span class="pun">()</span> <span class="pun">{</span>
      <span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Inside Rectangle::draw() method."</span><span class="pun">);</span>
   <span class="pun">}</span>
<span class="pun">}</span>

public class Rectangle implements Shape {

@Override

public void draw() {

System.out.println("Inside Rectangle::draw() method.");

}

Square.java

<span class="kwd">public</span> <span class="kwd">class</span> <span class="typ">Square</span> <span class="kwd">implements</span> <span class="typ">Shape</span> <span class="pun">{</span>
   <span class="lit">@Override</span>
   <span class="kwd">public</span> <span class="kwd">void</span><span class="pln"> draw</span><span class="pun">()</span> <span class="pun">{</span>
      <span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Inside Square::draw() method."</span><span class="pun">);</span>
   <span class="pun">}</span>
<span class="pun">}</span>

public class Square implements Shape {

@Override

public void draw() {

System.out.println("Inside Square::draw() method.");

}

Circle.java

<span class="kwd">public</span> <span class="kwd">class</span> <span class="typ">Circle</span> <span class="kwd">implements</span> <span class="typ">Shape</span> <span class="pun">{</span>
   <span class="lit">@Override</span>
   <span class="kwd">public</span> <span class="kwd">void</span><span class="pln"> draw</span><span class="pun">()</span> <span class="pun">{</span>
      <span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Inside Circle::draw() method."</span><span class="pun">);</span>
   <span class="pun">}</span>
<span class="pun">}</span>

public class Circle implements Shape {

@Override

public void draw() {

System.out.println("Inside Circle::draw() method.");

}

Step 3

Create a Factory to generate object of concrete class based on given information.
ShapeFactory.java

<span class="kwd">public</span> <span class="kwd">class</span> <span class="typ">ShapeFactory</span> <span class="pun">{</span>
   <span class="com">//use getShape method to get object of type shape </span>
   <span class="kwd">public</span> <span class="typ">Shape</span><span class="pln"> getShape</span><span class="pun">(</span><span class="typ">String</span><span class="pln"> shapeType</span><span class="pun">){</span>
      <span class="kwd">if</span><span class="pun">(</span><span class="pln">shapeType </span><span class="pun">==</span> <span class="kwd">null</span><span class="pun">){</span>
         <span class="kwd">return</span> <span class="kwd">null</span><span class="pun">;</span>
      <span class="pun">}</span>
      <span class="kwd">if</span><span class="pun">(</span><span class="pln">shapeType</span><span class="pun">.</span><span class="pln">equalsIgnoreCase</span><span class="pun">(</span><span class="str">"CIRCLE"</span><span class="pun">)){</span>
         <span class="kwd">return</span> <span class="kwd">new</span> <span class="typ">Circle</span><span class="pun">();</span>
      <span class="pun">}</span> <span class="kwd">else</span> <span class="kwd">if</span><span class="pun">(</span><span class="pln">shapeType</span><span class="pun">.</span><span class="pln">equalsIgnoreCase</span><span class="pun">(</span><span class="str">"RECTANGLE"</span><span class="pun">)){</span>
         <span class="kwd">return</span> <span class="kwd">new</span> <span class="typ">Rectangle</span><span class="pun">();</span>
      <span class="pun">}</span> <span class="kwd">else</span> <span class="kwd">if</span><span class="pun">(</span><span class="pln">shapeType</span><span class="pun">.</span><span class="pln">equalsIgnoreCase</span><span class="pun">(</span><span class="str">"SQUARE"</span><span class="pun">)){</span>
         <span class="kwd">return</span> <span class="kwd">new</span> <span class="typ">Square</span><span class="pun">();</span>
      <span class="pun">}</span>
      <span class="kwd">return</span> <span class="kwd">null</span><span class="pun">;</span>
   <span class="pun">}</span>
<span class="pun">}</span>

public class ShapeFactory {

//use getShape method to get object of type shape

public Shape getShape(String shapeType){

if(shapeType == null){

return null;

}

if(shapeType.equalsIgnoreCase("CIRCLE")){

return new Circle();

} else if(shapeType.equalsIgnoreCase("RECTANGLE")){

return new Rectangle();

return new Square();

}

return null;

}

Step 4

Use the Factory to get object of concrete class by passing an information such as type.
FactoryPatternDemo.java

<span class="kwd">public</span> <span class="kwd">class</span> <span class="typ">FactoryPatternDemo</span> <span class="pun">{</span>
   <span class="kwd">public</span> <span class="kwd">static</span> <span class="kwd">void</span><span class="pln"> main</span><span class="pun">(</span><span class="typ">String</span><span class="pun">[]</span><span class="pln"> args</span><span class="pun">)</span> <span class="pun">{</span>
      <span class="typ">ShapeFactory</span><span class="pln"> shapeFactory </span><span class="pun">=</span> <span class="kwd">new</span> <span class="typ">ShapeFactory</span><span class="pun">();</span>
      <span class="com">//get an object of Circle and call its draw method.</span>
      <span class="typ">Shape</span><span class="pln"> shape1 </span><span class="pun">=</span><span class="pln"> shapeFactory</span><span class="pun">.</span><span class="pln">getShape</span><span class="pun">(</span><span class="str">"CIRCLE"</span><span class="pun">);</span>
      <span class="com">//call draw method of Circle</span><span class="pln">
      shape1</span><span class="pun">.</span><span class="pln">draw</span><span class="pun">();</span>
      <span class="com">//get an object of Rectangle and call its draw method.</span>
      <span class="typ">Shape</span><span class="pln"> shape2 </span><span class="pun">=</span><span class="pln"> shapeFactory</span><span class="pun">.</span><span class="pln">getShape</span><span class="pun">(</span><span class="str">"RECTANGLE"</span><span class="pun">);</span>
      <span class="com">//call draw method of Rectangle</span><span class="pln">
      shape2</span><span class="pun">.</span><span class="pln">draw</span><span class="pun">();</span>
      <span class="com">//get an object of Square and call its draw method.</span>
      <span class="typ">Shape</span><span class="pln"> shape3 </span><span class="pun">=</span><span class="pln"> shapeFactory</span><span class="pun">.</span><span class="pln">getShape</span><span class="pun">(</span><span class="str">"SQUARE"</span><span class="pun">);</span>
      <span class="com">//call draw method of square</span><span class="pln">
      shape3</span><span class="pun">.</span><span class="pln">draw</span><span class="pun">();</span>
   <span class="pun">}</span>
<span class="pun">}</span>

public class FactoryPatternDemo {

public static void main(String[] args) {

ShapeFactory shapeFactory = new ShapeFactory();

//get an object of Circle and call its draw method.

Shape shape1 = shapeFactory.getShape("CIRCLE");

//call draw method of Circle

shape1.draw();

//get an object of Rectangle and call its draw method.

Shape shape2 = shapeFactory.getShape("RECTANGLE");

//call draw method of Rectangle

shape2.draw();

//get an object of Square and call its draw method.

Shape shape3 = shapeFactory.getShape("SQUARE");

//call draw method of square

shape3.draw();

}

Step 5

Verify the output.

Inside Circle::draw() method.
Inside Rectangle::draw() method.
Inside Square::draw() method.

Inside Circle::draw() method.

Inside Rectangle::draw() method.

Inside Square::draw() method.

Group C

Q.no 8

Step 1

Step 2

Step 3

Step 4

Step 5

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