Editing Flyweight pattern (section)

=== Structure ===
[[File:w3sDesign Flyweight Design Pattern UML.jpg|frame|none|A sample UML class and [[sequence diagram]] for the Flyweight design pattern.<ref>{{cite web|title=The Flyweight design pattern - Structure and Collaboration|url=http://w3sdesign.com/?gr=s06&ugr=struct|website=w3sDesign.com|access-date=2017-08-12}}</ref>]]

The above [[UML]] [[class diagram]] shows:

* the <code>Client</code> class, which uses the flyweight pattern
*the <code>FlyweightFactory</code> class, which [[Factory class|creates and shares <code>Flyweight</code> objects]]
* the <code>Flyweight</code> [[Interface (computing)|interface]], which takes in extrinsic state and performs an operation 
*the <code>Flyweight1</code> class, which implements <code>Flyweight</code> and stores intrinsic state

The sequence diagram shows the following [[Runtime (program lifecycle phase)|run-time]] interactions:

# The <code>Client</code> object calls <code>getFlyweight(key)</code> on the <code>FlyweightFactory</code>, which returns a <code>Flyweight1</code> object.
# After calling <code>operation(extrinsicState)</code> on the returned <code>Flyweight1</code> object, the <code>Client</code> again calls <code>getFlyweight(key)</code> on the <code>FlyweightFactory</code>.
# The <code>FlyweightFactory</code> returns the already-existing <code>Flyweight1</code> object.