Flyweight Design pattern - Implementation

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Flyweight Design pattern - Implementation

Flyweight Design pattern - Class Diagram

Shape.java

public interface Shape

{

void draw();

}

Circle.java

public class Circle implements Shape

{

private String    color;

private final int x      = 10;

private final int y      = 20;

private final int radius = 30;

public Circle()

{

}

public Circle( String color )

{

this.color = color;

}

public String getColor()

{

return color;

}

public void setColor( String color )

{

this.color = color;

}

@Override

public void draw()

{

System.out.println(this+" : Circle: Draw() [Color : " + color + ", x : " + x + ", y :" + y + ", radius :"

               + radius);

}

}

ShapeFactory.java

import java.util.HashMap;

public class ShapeFactory

{

private static final HashMap<String, Shape> shapeMap = new HashMap<String, Shape>();

public static Shape getShape( String shapeType )

{

Shape shape=null;

if( shapeType.equalsIgnoreCase("circle") )

{

shape = (Circle) shapeMap.get("circle");

if( shape == null )

{

shape = new Circle();

shapeMap.put("circle", shape);

System.out.println("Creating circle object with out any color in shapefactory : " + shape

               + "\n");

}

}

return shape;

}

}

FlyweightPatternDemo.java

public class FlyweightPatternDemo

{

private static final String colors[] = { "Red", "Green", "Blue", "Orange", "Black" };

public static void main( String[] args )

{

System.out.println("\n################ Red color Circles ####################");

for( int i = 0; i < 10; ++i )

{

Circle circle = (Circle) ShapeFactory.getShape("circle");

circle.setColor(colors[0]);

circle.draw();

}

System.out.println("\n############### Green color Circles ####################");

for( int i = 0; i < 10; ++i )

{

Circle circle = (Circle) ShapeFactory.getShape("circle");

circle.setColor(colors[1]);

circle.draw();

}

System.out.println("\n################ Blue color Circles ####################");

for( int i = 0; i < 10; ++i )

{

Circle circle = (Circle) ShapeFactory.getShape("circle");

circle.setColor(colors[2]);

circle.draw();

}

System.out.println("\n################ Orange color Circles ####################");

for( int i = 0; i < 10; ++i )

{

Circle circle = (Circle) ShapeFactory.getShape("circle");

circle.setColor(colors[3]);

circle.draw();

}

System.out.println("\n################ Black color Circles ####################");

for( int i = 0; i < 10; ++i )

{

Circle circle = (Circle) ShapeFactory.getShape("circle");

circle.setColor(colors[4]);

circle.draw();

}

}

}

Output

################ Red color Circles ####################

Creating circle object with out any color in shapefactory : Circle@10385c1

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Red, x : 10, y :20, radius :30

############### Green color Circles ####################

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Green, x : 10, y :20, radius :30

################ Blue color Circles ####################

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Blue, x : 10, y :20, radius :30

################ Orange color Circles ####################

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Orange, x : 10, y :20, radius :30

################ Black color Circles ####################

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

Circle@10385c1 : Circle: Draw() [Color : Black, x : 10, y :20, radius :30

See also:

Flyweight Design pattern - Introduction

Flyweight Design pattern - Real Time Example

Flyweight Design pattern - Class Diagram

Flyweight Design pattern - Sequence Diagram

Flyweight Design pattern - Key Points

All Design Patterns Links