SOA & BPEL:Building a Service With BPEL

and the Java EE Platform

Agenda

This session describes how

developers using Java™ Platform,

Enterprise Edition can create

composite applications using BPEL

with current Java EE tools and

application servers that support Java

Business Integration

Agenda

Why Services Why Composite Applications BPEL in the Mix A Java EE Based Composite Application Summary

Why Services?

SOA = an architectural principle for structuring systems that

SOA emphasizes the de-coupling of system components

New services are created from existing ones in a synergistic fashion

Strong service definitions are critical Services can be subsequently re-composed in

response to changing business requirements

What Are Services?

A function accessed using XML message exchange

Message exchanges have well known exchange patterns

Services are self-describing, usingmetadata (WSDL)

What Does a Service Do?

Transform data Route messages Query databases Orchestrate conversations Apply business logic Apply business policy Handle business exceptions Solicit approvals …

How Is a Service Implemented?

• XSLT• Enterprise JavaBeans™ (EJB™) technology• BPEL• SQL• XQuery• Routing table• Business rules• EDI transform• …

Service Oriented Architecture

In April 2006 the Object Management Group's (OMG) SOA Special Interest Group adopted the following definition for SOA Service Oriented Architecture is an architectural style for a Community of providers and consumers of services to achieve mutual value, that

– Allows participants in the communities to work together with minimal co-dependence or technology dependence

– Specifies the contracts to which organizations, people and technologies must adhere in order to participate in the community

– Provides for business value and business processes to be realized by the community

– Allows for a variety of technologies to be used to facilitate interactions within the community

Service Oriented Architecture

In March 2006 the OASIS group SOA Reference Model released its first public review draft.

This defines the basic principles of SOA that apply at all levels of a service architecture, from business vision through to technical and infrastructure implementation

– Service Oriented Architecture; a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains.

– It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations

Principles of SOA

Services share a formal contract Services are loosely coupled Services abstract underlying logic Services are composable Services are reusable Services are autonomous Services are stateless Services are discoverable

Benefits of SOA

Flexible (Agile) IT– Adaptable to changing business needs

Faster time to market– Reuse existing code, minimize new development

Business and process-driven– New business opportunities

Greater ROI– Leverage existing IT asset

Composite Applications

Composite applications are...applications! Comprised of heterogeneous parts

– Some existing parts– Some new parts

Composite applications != SOA Composite applications employ SOA principles

– Features exposed as Web services– Standards-based interaction between services– Described by standards-based artifacts– Are themselves composable

Purchase Service

Purchase Service Functions

Composite Applications—Summary

A composite application is a collection of existing and independently developed applications and new business logic, orchestrated together into a brand new solution of a business problem that none alone can solve

Such an application looks to the user like a regular new interactive application, yet in reality it may be only 10 percent new and 90 percent an assembly of pre-existing components or data;

The “glue” that brings a composite application together is integration technology

WS-BPEL Works With WSDLWeb Services Business Process Execution Language

Web services are described in WSDL– Operations are message exchanges– Each operation represents an individual unit of action

We need a way to orchestrate these operations with multiple web services in the right order to perform a Business process

– Sequencing, conditional behavior etc.

BPEL provides standard-based orchestration of these operations

What is BPEL?

XML-based language used to specify business processes based on Web Services

BPEL processes describe– Long running, stateful, transactional, conversations

between two or more partner web services BPEL is key to implementing SOA Big Rules

– Conversational– Mostly Async– XML Document-based– Orchestrated

BPEL Is a Web ServiceSequencing Language

Process defines “conversation” flow chart– Conversation consists of only WSDL-described

message exchanges– BPEL provides and consumes WSDL defined

services Process instance is a particular conversation

following the chart– Execution systems can support multiple

concurrent conversations

BPEL “Fixes” WSDL

WSDL: unordered set of operations– Operations are message exchanges

• Need rules for ordering • Support for sequencing • Support for concurrency • Choreography with external entities

Orchestration vs. Choreography

Orchestration– An executable business process describing a flow from the

perspective and under control of a single endpoint (commonly: Workflow)

– BPEL handles Orchestration

Choreography (WSDL)– The observable public exchange of messages, rules of

interaction and agreements between two or more business process endpoints

– WSDL handles Choreography

BPEL: Relationship to Partners

Business Process Needs To...

Co-ordinate asynchronous communication between services

Correlate message exchanges between parties

Implement parallel processing of activities

Implement compensation logic(Undo operations)

Manipulate/transform data between partner interactions

Support for long running business transactions and activities

Handle exception handling Need for universal data

model for message exchange

BPEL Document Structure

BPEL Activities

Basic Activities• <invoke>• <receive>• <reply>• <assign>• <throw>• <wait>• <empty>

Structured Activities• <sequence>• <while>• <pick>• <flow>• <scope>• <compensate>• <switch>• <link>

BPEL: Basic Activities

<invoke> To invoke a one-way or request/response operation on a

portType offered by a partner <receive>

To do a blocking wait for a matching message to arrive Can be the instantiator of the business process

<reply> To send a message in reply to a message that was

received through a <receive> The combination of a <receive> and a <reply> forms a

request-response operation on the WSDL portType for the process

BPEL: Basic Activities

<assign>– Can be used to update the values of variables with new data

<throw>– Generates a fault from inside the business process

<wait>– Allows you to wait for a given time period or until a certain time

has passed <empty>

– Allows you to insert a "no-op" instruction into a business process– This is useful for synchronization of concurrent activities, for

instance

BPEL: Structured Activities

• <sequence> Perform activities in sequential order

• <flow> Perform activities in parallel

• <switch> Conditional choice of activities

• <scope> Enclose multiple activities in a single scope

Example Business Process

Sample Activities in BPEL

BPEL: Relationship to Partners

Why Do You Care on BPEL?

• In SOA-enabled environment, you are more likely to

build an application by orchestration various services

via BPEL

• You will probably use BPEL design tool to create a

BPEL document

• The BPEL document is then executed by BPEL

engine– Highly likely in JBI enabled platform

Example ScenarioThe Loan Processing Composite Application

WSDL: Schema Types (1)LoanProcessor.wsdl

WSDL: Schema Types (1)LoanProcessor.wsdl

BPEL Header

BPEL: Partner Links & Variables

BPEL: Partner Links & Variables

BPEL: …the Decision

BPEL: …the Decision, Reply

Loan Processor Service (EJB 3)

What Are the Artifacts?

Service Consumption (Java APIs)for XML Web Services (JAX-WS 2.0)

Runtime: Java EE Platformand Java Business Integration

Java Business Integration serves as messaging infrastructure Java EE web services interact through Java Business

Integration Java Business Integration bindings allow remote consumers

and providers Add other service technologies as Java Business

Integration components Transparent to programmer using Java EE

technology Reuse without re-coding

Java Business Integration (JSR 208)

Web Service Orchestration

Author, design, deploy and test business processes with the BPEL Designer

– Supports the BPEL 2.0 constructs– Adds powerful methods for visual authoring– Step through debugging support– Built in testing capability for unit testing

BPEL Mapper for BPEL variable assignments– Quickly generate XPath expressions

Deploy to the built in BPEL engine– Running as a service engine in the JBI environment within

the provided Sun Java System Application Server

Summary

SOA enables flexible and agile enterprise application architecture

Services can be created and used using a variety of Java EE technologies

BPEL is a service orchestration language for creating stateful composite applications

Services can be re-implemented using other technologies as long as service interface is preserved without changing consumers

Java Business Integration is the enabling infrastructure

Questions?