Design Pattern -- from Java to Ruby Richard E kohe www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Richard

E kohe

Why use Design Pattern For reuse www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

For reuse

Why use Design Pattern For communication www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Define a Node interface, all of leaf nodes and internal nodes should implements the interface, internal nodes has a list that includes other internal nodes and leaf nodes and it can add sub-nodes. But leaf node can’t have add sub-node method. Multi-level Menus?

For communication

Why use Design Pattern For communication www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Composite Pattern Multi-level Menus?

For communication

Difference from java to ruby Classes are Objects Messages, not function call Duck Typing Mixin www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Classes are Objects

Messages, not function call

Duck Typing

Mixin

Singleton Pattern ensures a class has only one instance, and provides a global point of access to it www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

ensures a class has only one instance, and provides a global point of access to it

Singleton Pattern www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development You are my only wife You are my only husband

Singleton Pattern -- java Eager loading Lazy loading www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Eager loading

Lazy loading

Singleton Pattern -- ruby Ruby built-in singleton www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Ruby built-in singleton

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Built-in (Singleton) www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Ruby for Design Pattern

Built-in (Singleton)

Observer Pattern defines a one-to-many dependency between objects so that when one object changes state, all of its dependents are notified and updated automatically www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

defines a one-to-many dependency between objects so that when one object changes state, all of its dependents are notified and updated automatically

Observer Pattern www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Temperature Detector Subscribe Notify Notify Temprature changed

Observer Pattern -- java www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Observer Pattern -- java www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Observer Pattern -- java Java built-in observer www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Java built-in observer

Observer Pattern -- ruby Ruby built-in observer www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Ruby built-in observer

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Built-in (Singleton, Observer ) Mixin www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Ruby for Design Pattern

Built-in (Singleton, Observer )

Mixin

Iterator Pattern provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation

Iterator Pattern www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Count 1 2 3 10

Iterator Pattern -- java www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Merb - Offshore Web Development External Iterator

External Iterator

Iterator Pattern -- java www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Merb - Offshore Web Development Internal Iterator

Internal Iterator

Iterator Pattern -- ruby Internal Iterator .each www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Internal Iterator .each

Built-in (Singleton, Observer, Iterator ) Mixin www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Ruby for Design Pattern

Built-in (Singleton, Observer, Iterator )

Mixin

returns an instance of one of several possible classes, depending on the data provided to it. www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Simple Factory Pattern

returns an instance of one of several possible classes, depending on the data provided to it.

www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Simple Factory Pattern

www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Simple Factory Pattern -- java

www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Simple Factory Pattern -- java

Classes are Objects www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Simple Factory Pattern -- ruby

Classes are Objects

Built-in (Singleton, Observer, Iterator)‏ Mixin Classes are Objects www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Ruby for Design Pattern

Built-in (Singleton, Observer, Iterator)‏

Mixin

Classes are Objects

encapsulates a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations. www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Command Pattern

encapsulates a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.

www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Command Pattern Increase temperature command Decrease temperature command

www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Command Pattern -- java

Proc www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Command Pattern -- ruby

Proc

Built-in (Singleton, Observer, Iterator)‏ Mixin Classes are Objects Proc www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Ruby for Design Pattern

Built-in (Singleton, Observer, Iterator)‏

Mixin

Classes are Objects

Proc

Make use of ruby advantage www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development Other Design Patterns

Principle DRY – Don't Repeat Yourself Convention Over Configuration www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

DRY – Don't Repeat Yourself

Convention Over Configuration

Resources Design Pattern – Elements of Reusable Object-Oriented Software Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides Head First Design Pattern Kathy Sierra, Bert Bates Design Pattern in Ruby Russ Olsen www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development

Design Pattern – Elements of Reusable Object-Oriented Software

Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides

Head First Design Pattern

Kathy Sierra, Bert Bates

Design Pattern in Ruby

Russ Olsen

Q&A happy to discuss and fix my mistakes www.ekohe.com Web Development & Graphic Design China Ruby on Rails Development - Rails Consulting - Rails Services - Merb - Offshore Web Development