example

FlyWeightExample.java

// Flyweight object interface
public interface CoffeeOrder {
    public void serveCoffee(CoffeeOrderContext context);
}
// ConcreteFlyweight object that creates ConcreteFlyweight 
public class CoffeeFlavor implements CoffeeOrder {
    private String flavor;
    public CoffeeFlavor(String newFlavor) {
        this.flavor = newFlavor;
    }
    public String getFlavor() {
        return this.flavor;
    }
    public void serveCoffee(CoffeeOrderContext context) {
        System.out.println("Serving Coffee flavor " + flavor + " to table number " + context.getTable());
    }
}
 
public class CoffeeOrderContext {
   private int tableNumber;
 
   public CoffeeOrderContext(int tableNumber) {
       this.tableNumber = tableNumber;
   }
 
   public int getTable() {
       return this.tableNumber;
   }
}
 
import java.util.HashMap;
import java.util.Map;
//FlyweightFactory object
public class CoffeeFlavorFactory {
    private Map<String, CoffeeFlavor> flavors = new HashMap<String, CoffeeFlavor>();
    public CoffeeFlavor getCoffeeFlavor(String flavorName) {
        CoffeeFlavor flavor = flavors.get(flavorName);
        if (flavor == null) {
            flavor = new CoffeeFlavor(flavorName);
            flavors.put(flavorName, flavor);
        }
        return flavor;
    }
    public int getTotalCoffeeFlavorsMade() {
        return flavors.size();
    }
}
 
public class TestFlyweight {
   /** The flavors ordered. */
   private static CoffeeFlavor[] flavors = new CoffeeFlavor[100];
   /** The tables for the orders. */
   private static CoffeeOrderContext[] tables = new CoffeeOrderContext[100];
   private static int ordersMade = 0;
   private static CoffeeFlavorFactory flavorFactory;
   public static void takeOrders(String flavorIn, int table) {
       flavors[ordersMade] = flavorFactory.getCoffeeFlavor(flavorIn);
       tables[ordersMade++] = new CoffeeOrderContext(table);
   }
 
   public static void main(String[] args) {
       flavorFactory = new CoffeeFlavorFactory();
       takeOrders("Cappuccino", 2);
       takeOrders("Cappuccino", 2);
       takeOrders("Frappe", 1);
       takeOrders("Frappe", 1);
       takeOrders("Xpresso", 1);
       for (int i = 0; i < ordersMade; ++i) {
           flavors[i].serveCoffee(tables[i]);
       }
       System.out.println(" ");
       System.out.println("total CoffeeFlavor objects made: " +  flavorFactory.getTotalCoffeeFlavorsMade());
   }
}