SCA Tutorial Part1 Asia-Updated

8/8/2019 SCA Tutorial Part1 Asia-Updated

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OSOA Collaboration | 30th May 2007 | SOA Roadmap

Service Component Architecture(SCA) Tutorial : Part 1

Mike Edwards - IBMAnish Karmarkar OracleJim Marino BEA


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OSOA Collaboration | SOA Roadmap

Service Component Architecture

A model for building components, assembling them intoapplications, and deploying them to various runtimeenvironments

Components can be built from new or existing code usingSOA principles

vendor-neutral supported across the industry

language-neutral components written using any language

technology-neutral use any communication protocols andinfrastructure to link components


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Part 1 Outline Composite example

Implementation using Java component implementation

Introduction to SCA concepts

Advanced composition nested composites

Packaging and deployment

Extension points

Component Implementation types Spring Framework

BPEL

Demonstrations


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Part 2 Outline

Bindings

Web service binding

JMS binding

EJB session bean binding

Policies Intents and Policy Sets

Security

Reliable Messaging

Transactions


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Warehouse

Service

WarehouseComposite

WarehouseBroker

Component

Warehouse

Component

EventLog

Component

OrderProcessing

Service

OrderProcessingComponent

EventLogReference

ExternalWarehouse

Reference

Payments

Component

PaymentService

AccountsComposite

ExternalBanking

Reference

Accounts

Ledger

Component

Example SCA assembly


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Service

AccountService

ReferenceStockQuote

Service

AccountData

ServiceComponent

bigbank.accountcomposite

AccountService

Component

Service

AccountService

ReferenceStockQuote

Service

AccountData

ServiceComponent

Simple Example


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XML Representation


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Java Implementation Example:Service Interface

package org.example.services.account;

@Remotable

public interface AccountService {

public AccountReport getAccountReport(String customerID);}

Interface is callable

remotelyeg. as a Web service


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Java Implementation Example Implementation (part 1)package org.example.services.account;

import org.osoa.sca.annotations.*;

@Service(AccountService.class)

public class AccountServiceImpl implements AccountService {

private String currency = "USD";

private AccountDataService accountDataService;

private StockQuoteService stockQuoteService;

public AccountServiceImpl(@Property("currency") String currency,

@Reference("accountDataService") AccountDataService dataService,

@Reference("stockQuoteService") StockQuoteService stockService) {

this.currency = currency;

this.accountDataService = dataService;

this.stockQuoteService = stockService;

} // end constructor

Defines theservice interface

Defines a propertycurrency

Defines referencesaccountDataServiceandstockQuoteService


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Java Implementation Example Implementation (part 2)

public AccountReport getAccountReport(int customerID)

throws AccountDataUnavailableException {

AccountReport accountReport =

accountDataService.getAccountReport(customerID);

List stocks = accountReport.getStocks();

List stockValues =

stockQuoteService.getValues( stocks, currency );

accountReport.setStockValues( values );

return accountReport;

}

} // end class

Get the basic accountreport using theaccount data service

Obtain up to datestock values using thestock quote service

Update the accountreport with the latest

stock values


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SCA Java Implementation principles

Code only to business interfaces

Dont program to SCA, just program

Use Java idioms Minimal middleware APIs used only in special cases

Principles apply to other languages

Components declare both the servicesthey offer and referencesto other services they need

Injection of required service References and Property values

via constructor

via setter methods

via direct field injection

Java annotations for SCA elements

services, references, properties

+ more advanced features such as intents, bindings


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Component

SCA Concepts: Component

Services

Business functionprovided to clientsthrough an interfacecontract

ReferencesImplementationdependency on an

external service

PropertiesImplementationconfiguration attribute

ImplementationThe implementation codefor the component. In anyone of many languages,eg. Java, BPEL, C++, PHP,Composite.


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SCA Concepts: Wire, Interface, Binding

Component

WireConnects services to references

Component

BindingAccess mechanism used by services andreferences. For example, Web services binding,JMS binding, EJB Session bean binding

InterfaceDescription of business functions of services& references. For example, Java interface,WSDL 1.1 portType, WSDL 2.0 interface


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Bigbank Composite - multiple components,service, reference & property


AccountService

Component

Service

AccountService

ReferenceStockQuoteService

AccountDataServiceComponent



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StockQuotebigbank.accountcomposite

AccountServiceComponent

ServiceAccountService





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Reuse in SCA

Inclusion Recursive composition

Implementation reuse through configurable components Reusable services through composite references


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ComponentType

Describes component implementation type details

Services

References

Properties

Extensibility elements

Can be introspected from the implementationor specified inan XML sidefile

Typically will be introspected from the implementation

Component implementations may use annotations to specify

componentType information eg Java


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Java Implementation Example: componentType


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Top-Down Design: constrainingType

constrainingType

Implementation independent

Specifies the shape -- constraints in terms ofservices/references/properties

composites, components, componentType and implementations canbe constrained using the constrainingType attribute

Allows an architect to specify constrainingTypes which can be usedby developers as a template

SCA provides runtime validation of artifacts with its constrainingType


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constrainingType Example

EURO


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Recursive Composition

Composites and Implementations look the same

services

references

properties

composites have associated ComponentType

Recursive composition = nesting of composites composite can be a component implementation in a higher level

composite

promotes reuse of assemblies

as component implementation

component can be implemented by atomic implementation or bycomposite


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Implementing AccountDataService Using AComposite











implements

Service

AccountDataServiceAccountData Logging

bigbank.accountdata


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AccountDataService ComponentType


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bigbank.account Composite (recursion)

EURO


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Packaging and Deployment: Domains Composites deployed, configured into SCA Domain

Defines the boundary of visibility for SCA

Typically an area of functionality controlled by single

organization/division E.g.: accounts

Configuration represented by virtual composite

potentially distributedacross a network of nodes

contains components, services, references, wires

configured using composites

Composites make deployment simpler

individual composites created, deployed independently

may contain only wires or components or externally providedservices or references

Abstract services provided for management of the domain


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Packaging and Deployment: Contributions

Contributions hold artifacts available for use in the Domain

Package containing artifacts necessary for SCA

SCA defined artifacts

E.g.: composites, constrainingType, etc

Non-SCA defined artifacts

E.g.: WSDL, XML schema, Java classes, object code etc

Packaging must be hierarchical Metadata included in the META-INF directory

*

*

*

Interoperable packaging format: ZIP Other formats possible: filesystem directory, OSGi bundle, JAR file


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SCA Runtime Example

SCA PHP Container

Assigned to be

hosted by SCAJava container Assigned to be

hosted by SCACPP container

Runtime Topology

DeploymentMapping

Service Compositions

SCA Domain

bigbank.accountmanagement

bigbank.stockquote

SCA JEE Containers SCA CPP Containers

SCA Java Containers

SCA BPEL Container


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Assembly: Summary

SCA Assembly models systems composed of reusable services

A model for service-based system:

construction

assembly

deployment

Heterogeneity

Multiple languages

Multiple container technologies

Service access methods

Metadata driven


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Component Implementation Types

SCA supports a number of programming models and technologies

for authoring components

The SCA Java Implementation type based on POJOs

Spring

EJB

BPEL C++

PHP

In the future, potentially others


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Spring Framework Component Implementation

SCA = integration at coarse-grained level

Spring = integration at fine grained level

Spring application context used as component implementation SCA component implemented by a collection of Spring beans

Two ways:

1. No SCA-related metadata in Spring

2. SCA-related metadata specified as Spring beans

sca:service

sca:reference

sca:property

Uses

...

SCA


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Bigbank implementation using SpringAccountService component


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BPEL Component Implementation

SCA and BPEL are complementary

BPEL provides business sequencing & orchestration of services

SCA provides a compositional view of interconnection of service components

Supports WS-BPEL 1.1 and 2.0

Uses WSDL interfaces

SCA service = partnerLink with single role belonging to the BPEL process

SCA reference = partnerLink with single role belonging to partner

When partnerLink defines two roles, directionality defines whether it is a serviceor a reference

SCA


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BPEL Component Implementation (cont.)

SCA extensions for BPEL (not mandatory)

Attribute sca:property on a variable declaration defines a property

Element sca:multiReference on a variable declaration defines a multivaluedreference (multiple partners for one partnerLink, called in sequence)

Uses


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SCA models systems built using a Service Oriented

Architecture

supports Service Implementation, Service Assembly

open to many kinds of service implementation

open to many types of service access

declarative intent & policy approach to application of

Security & Transaction

Summary

SCA


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Demonstrations

IBM Demo: HelloWorld sample with a callback (SCA V0.95)

Oracle Demos: Oracle Fusion Middleware (SCA 0.95) Overview

Simple SayHello Example Using Jdeveloper (Synchronous)

Simple HelloWorld Example (Asynchronous)

OrderBooking Application

BEA Demo Based on the Fabric3 open source SCA implementation

(www.fabric3.org)

Component provisioning in distributed SCA domain across multipleJVMs

Java SCA 1.0 programming model support

SCA


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IBM Demo: HelloWorld Sample with CallbackHelloWorldWSClient

HelloWorldService

Component ReferenceHello Service

BindingWeb Service

Implementation- Java

JSP

HelloWorldWS

HelloWorldServiceComponent

Implementation- Java

ServiceHello Service

Service

WSDL PortType

Binding

Web Service

Service

PortTypeWSDL

SCA


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IBM Demo: HelloWorld Sample with Callback - Client

HelloWorldService

SCA


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IBM Demo: HelloWorld Sample with Callback - Service

HelloWorldServiceComponent

SCA


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Oracle Demo: Fusion (SCA 0.95) Overview

JCA

JMS

HTTP SCA Runtime(Fusion Middleware)

Normalized message busComponent lifecycle managementInter-component wiringPolicy enforcement (binding

independent)Monitoring

MDS

UDDI

BPEL Routing RulesScheduler

J2EE + Spring

Bindings

Service Engines

SCA


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Oracle Demo: SayHello Example

(Synchronous)

SayHello

SayHelloComponentServiceSoapService1

Binding

Web Service

Service

WSDL PortType

Implementation- BPEL


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Oracle Demo: HelloWorld Example

(Asynchronous)

HelloWorld

HelloWorldComponentServiceSoapService1

Binding

Web Service

Service

WSDL PortType

Implementation- BPEL


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Oracle Demo: OrderBooking Application

OrderProcessor

Component

OrderFulfillment

ComponentApproveOrder

Component

ApprovalRequired

Component

SelectManufacturerComponent

EventLoggerComponent

Order

.

.

....

binding.ws

binding.jca

Implementation.eventAgent

Implementation.workflow Implementation.mediator

Implementation.bpel

Implementation.decision

SCA


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...

SCA


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BEA/Fabric3 Demo Open source CodeHaus Foundation project (www.fabric3.org) Apache Licensed

Built around a small embeddable kernel that is highly extensible

Less than 1MB

Extension ecosystem, e.g. Spring, OpenJPA

Focused on

Implementation quality

SCA 1.0 support

Agile development experience and SDK

Management of distributed SCA domains

Federated deployment to multiple runtime types

WebLogicCluster

SCA DomainController

Servlet

Engine

OSGi

OtherContainers

Domains are heterogenous

Fabric3 may be embedded in avariety of containers

Manage and provisioncomponents

SCA


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BEA/Fabric3 Demo

Provision and deploy a Calculator Composite

Calculator service wired to Add, Subtract, Multiply and Divide services

SCA Domain

SCA Composite

Service Node

Process the composite,

resolve wires andallocate to runtimenodes

Provision componentsto multiple runtimenodes

Instantiate componentson runtime nodes

1

2

3

4

Deploy the SCAcomposite


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OSOA Collaboration | 30th May 2007 | SOA Roadmap

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SCA Tutorial Part1 Asia-Updated

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