Design Patterns in Java - Flyweight Pattern

Flyweight Pattern

• Minimize memory use by sharing data with similar typed object
• Optimization pattern
• Ex.  java.lang.String, inventory, shopping cart

Ex.

public class Catalog {

    private Map<String, Item> items = new HashMap<String, Item>();

    //factory

    public Item lookup(String item) {

        if (!items.containsKey(item)) {

            items.put(item, new Item(item));

        }

        return items.get(item);

    }

}

class Item {

    String name;

    public Item() {

    }

    Item(String item) {

        this.name = name;}

}