Your SlideShare is downloading. ×
Stoop 440-adaptor
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Stoop 440-adaptor

262
views

Published on

Published in: Technology

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
262
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
3
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. S.Ducasse 1 QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture. Stéphane Ducasse Stephane.Ducasse@univ-savoie.fr http://www.listic.univ-savoie.fr/~ducasse/ Adapter
  • 2. S.Ducasse 2 License: CC-Attribution-ShareAlike 2.0 http://creativecommons.org/licenses/by-sa/2.0/
  • 3. S.Ducasse 3 Adapter • Convert the interface of a class into another interface clients expect. • Adapter lets classes work together that couldn't otherwise because of incompatible interfaces. • Aka:Wrapper
  • 4. S.Ducasse 4 Motivation • Sometimes a toolkit class designed for reuse isn't reusable only because its interface doesn't match the domain-specific interface an application requires.
  • 5. S.Ducasse 5 Adapter Solution
  • 6. S.Ducasse 6 Possible Adapter Structures
  • 7. S.Ducasse 7 Participants • Target (Shape) • defines the domain-specific interface that Client uses. • Client (DrawingEditor) • collaborates with objects conforming to the Target interface. • Adaptee (TextView) • defines an existing interface that needs adapting. • Adapter (TextShape) • adapts the interface of Adaptee to the Target interface.
  • 8. S.Ducasse 8 Collaborations • Clients call operations on an Adapter instance. In turn, the adapter calls Adaptee operations that carry out the request.
  • 9. S.Ducasse 9 About Identity • A decorator and its component aren't identical. • A decorator acts as a transparent enclosure. But from an object identity point of view, a decorated component is not identical to the component itself. • If the decorator is wrapping, then identity of the object may change. • Good at construction time, but else should “adapt” the references from the decorated to the decorator.
  • 10. S.Ducasse 10 Consequences • More flexibility than static inheritance. Dynamic addition of properties • Avoids feature-laden classes high up in the hierarchy. • Lots of little objects.
  • 11. S.Ducasse 11 Implementation • Interface conformance. A decorator object's interface must conform to the interface of the component it decorates. ConcreteDecorator classes must therefore inherit from a common class (at least in C++). • Omitting the abstract Decorator class. There's no need to define an abstract Decorator class when you only need to add one responsibility. • Keeping Component classes lightweight. Component should specify an interface, decorators are then easier to define
  • 12. S.Ducasse 12 Wrapping or not? Conforming or not • With decorator • With strategies
  • 13. S.Ducasse 13 Strategies? • Strategies are a better choice when the Component class is heavyweight, thereby making the Decorator pattern too costly to apply. • The Strategy-based approach might require modifying the component to accommodate new extensions. • - a strategy can have its own specialized interface, • - a decorator's interface must conform to the component's. • A strategy needs only define the interface for rendering a border, which means that the strategy can be lightweight even if the Component class is
  • 14. S.Ducasse 14 Known Uses • VisualWorks Wrapper hierarchy • Stream Decorators inVisualWorks: • BOSSTransporter is a stream decorator • FormattedStream is a stream decorator

×