From Systems to Services

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From Systems to Services

How we can collaborate in the new paradigm?

Randy Ballew, Chief Technology Architect, IST-AS Steve Masover, Architecture Group, IST-AS

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Overview

• What is "software as services"?

• Design Fundamentals & Implementation Concepts:

- Design Patterns

- Unified Modeling Language (UML)

- Model-Driven Architecture (MDA)

• MDA Tools: AndroMDA

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The Service Request Model

• siloed development

• opaque orchestration

“Sure, we can have that special-order widget for you in about six months!”

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Service Oriented Architecture

In an SOA environment, nodes on a network make resources available to other participants in the network as independent services that the participants access in a standardized way. Most definitions of SOA identify the use of Web

services (e.g., using SOAP or REST) in its implementation. However, one can implement SOA using any service-based technology.

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Student Services @ Berkeley

• student registration validation

• roster

• contact information

• degree validation

• transcript

• ???

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Enterprise Service Bus

• An infrastructure designed to support the interactions of

services in a service-oriented architecture

• Becomes useful once we reach a critical mass of

available services

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Designing and Implementing

Services

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Information Services & Technology:

CIO’s Point of View

• CIO has been showing this slide for months: what he & cabinet are thinking vis-à-vis campus IT

• SOA enables flexibility • Flexibility enables

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Fitting it all together

service =

model-driven-software-development *

(domain-driven-design % design-patterns)

• Design Analysis Patterns - thinking in bigger boxes

• Design Patterns - implementation using tested engineering principles • Unified Modeling Language (UML): representing our designs

• Model Driven Architecture (MDA) - automating major pieces of development efforts

We’re going to look at how these elements converge to

enable delivery of software as services:

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Software Models the Real World

no matter what language it’s coded in...

<?php class Student { var $Name; var $Gender; var $GradeLevel; var $Schedule; /* Constructor */ function Student($studentName) { $this->Name = $studentName; } […] ?> class Course { ...

boolean register ( Student s ) {

Transcript t = s.getTranscript(); if ( t.successfullyCompleted ( c2 ) return true; else return false; ... } ... }

public class Student {

private String name; private int ID;

public double test1, test2, test3; private static int nextUniqueID = 1; Student(String theName) { name = theName; ID = nextUniqueID; nextUniqueID++; } […]

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Fitting it all together

service =

model-driven-software-development *

(domain-driven-design % design-patterns)

• Design Analysis Patterns - thinking in bigger boxes

We’re going to look at how these elements converge to

enable delivery of software as services:

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Domain Design: Analysis Patterns

Viewing our business as re-usable software objects:

People

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Fitting it all together

service =

model-driven-software-development *

(domain-driven-design % design-patterns)

• Design Patterns - implementation using tested engineering principles

• Unified Modeling Language (UML): representing our designs • Model Driven Architecture (MDA) - automating major pieces of development efforts

We’re going to look at how these elements converge to

enable delivery of software as services:

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Design Patterns:

general repeatable solutions to commonly-occurring problems in software design

•It works, it’s quick

•Hard to extend, maintain, scale •The “ready, fire, aim” pattern • Quick & Dirty (rarely & always)

• It’s established, widely adopted:

- 27K on Sun; 12K IEEE; 10K IBM; 1K Microsoft - standard vocabulary for OO programmers

• Extensible, maintainable, scalable: longer-term benefits of up-front cost

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Design Patterns:

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MVC is the

pattern of choice for

webapp development frameworks

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Fitting it all together

service =

model-driven-software-development *

(domain-driven-design % design-patterns)

• Design Patterns - implementation using tested engineering principles • Unified Modeling Language (UML): representing our designs

We’re going to look at how these elements converge to

enable delivery of software as services:

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What is Unified Modeling

Language?

• an industry standard and widely utilized language for

modeling structures, behaviors, and interactions.

• a common shorthand with which software developers can

communicate with each other, and record design decisions

• a way to jumpstart the actual coding of a software

component, service, or application using tools that generate

code from UML

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UML: What can be modeled?

Structure

: Class Diagram, Object Diagram, Component Diagram, Composite Structure Diagram, Package Diagram, and Deployment Diagram.

Behavior

: Use Case Diagram (used by some methodologies

during requirements gathering); Activity Diagram, and State Machine Diagram.

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UML: Object Diagram

• a high-level “Class Diagram” is often called an “Object Diagram” or “Object Model”

•relationships between various structures (representing things like

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UML: Class Diagram

• a more elaborate Class Diagram, courtesy of Scott Ambler and agilemodeling.com

• might be a very early draft of someone’s attempt to model people at a University

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UML: Activity Diagram

• an activity diagram models behavior

• the application has users, and users have profiles (information that describes them)

• when we get to a real-world

example you'll see the significance of the <<stereotypes>> - they're a shorthand for describing the type of component represented in a diagram element

• This diagram shows that:

• system finds appropriate profile given an identifying key • a <<Front End View>> is generated - maybe a web page

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Fitting it all together

service =

model-driven-software-development *

(domain-driven-design % design-patterns)

• Model Driven Architecture (MDA) - automating major pieces of development efforts

We’re going to look at how these elements converge to

enable delivery of software as services:

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MDA: Model Driven

Architecture

http://www.omg.org/mda/

• Platform-independent models (PIMs)

document the functionality and behavior of an application separate from the

technology-specific code that implements it

• Platform-specific models (PSMs) specifies functionality in terms of an implementation technology

• Modeling in a PSM enables automated code generation

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AndroMDA: Generating code

from UML

• PIM

• PSM

• Code Generation based

on design patterns

embedded in templates

• Manual coding is

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A UCB Example: CoA

Validation

• Chartstrings represent constructs on General Ledger

• Departments across campus submit transactions keyed on

Chartstrings

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Activity Diagram: Interactive

Chart String Validation

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Class Diagram:

ValidationService

• <<WebService>>, <<WebServiceOperation>>

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Demo:

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Conclusions / Take-aways

• Using analysis and design patterns, your software is

built on the shoulders of giants

• With MDA, you’re writing business code, not

plumbing

• “Software development is a lot like swimming -

dangerous to do alone”

- Scott Ambler, http://www.ambysoft.com/

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References

•Design Patterns, Gamma, Helm, Johnson, Vlissides; Headfirst Design

Patterns, Freeman & Freeman; Analysis Patterns, Fowler

• UML Distilled: A Brief Guide to the Standard Object Modeling Language, Fowler & Scott

•MDA Explained: The Model Driven Architecture--Practice and Promise, Kleppe, Warmer, & Bast

• Enterprise Patterns and MDA: Building Better Software with Archetype

Patterns and UML, Arlow & Neustadt

• An Introduction to Model Driven Architecture, Brown & Conallan (part 1 of 3 is at: http://www-128.ibm.com/developerworks/rational/library/3100.html ) • Object Management Group: http://www.omg.org