Business Process Execution Language (BPEL) Pınar Tekin

What is BPEL? BPEL stands for Business Process Execution Language, and comes from a standards consortium consisting of BEA Systems, IBM, and Microsoft. BPEL is an XML-based language for enabling task sharing across multiple enterprises using a combination of Web services. BPEL is based on the XML schema, simple object access protocol (SOAP), and Web services description language (WSDL).

What is BPEL? BPEL directly addresses these business process challenges: Coordinating asynchronous communication between services Correlating message exchanges between parties Implementing parallel processing of activities Manipulating data between partner interactions Supporting long running business transactions and activities, and providing consistent exception handling.

What is BPEL? The BPEL language enables you to define how to: Send XML messages to, and asynchronously receive XML messages from, remote services Manipulate XML data structures Manage events and exceptions Design parallel flows of process execution Undo portions of processes when exceptions occur

The Role of BPEL The BPEL specification defines the syntax and semantics of the BPEL language, which contains a variety of process flow constructs. It allows for – Conditional branching, – Parallel process flows – Nested sub-processes – Process joins

Oracle BPEL Process Manager Web service standards such as XML, SOAP, and WSDL Dehydration (enables the states of long-running processes to be automatically maintained in a database) and correlation of asynchronous messages Service-oriented architecture (SOA) Parallel processing of tasks Fault handling and exception management during both design time and run time Event timeouts and notifications Compensation mechanisms for the implementation of long-running transactions

Oracle BPEL Process Manager Scalability and reliability of processes Management and administration of processes Version control Audit trails for tracing business flow history Installation on multiple operating systems and integration with multiple application servers (for example, Oracle Application Server, BEA WebLogic, and JBoss) and databases. Oracle BPEL Process Manager adds value and ease of use to BPEL functionality by providing support for the following in JDeveloper BPEL Designer: Transformations, workflows, worklists, notifications, and sensors Technology adapters (file, FTP, database, advanced queuing (AQ), Java Messaging Service (JMS), and Oracle Applications for Oracle E- Business Suite)

JDeveloper BPEL Designer JDeveloper BPEL Designer is integrated with Oracle JDeveloper. Oracle JDeveloper is an integrated development environment (IDE) for building applications and Web services using Java, XML, and SQL standards.

Composite

Partner Links Partner Link describes the shape of the relationship with a partner by describing the Port Types used in a peer to peer relationship Example: <partnerLink name=“Invoice” partnerLinkType=“inv:InvoiceType” partnerRole=“InvoiceServiceProvider”/> <partnerLink name=“Employee” partnerLinkType=“emp:EmployeeType” partnerRole=“EmployeeServiceProvider”/>

Partner Links process partner link partner link type Peer-to-peer conversational partner relationship WSDL port type myRole Provided port type WSDL port type partnerRole Required port type receive Inbound request – service provided by the process invoke Outbound request – service required by the process

Partner Links

Variable Element Variable construct is used to state information related to workflow logic Variables can contain entire messages and data sets formatted as XSD schema types Example: <variable name=“EmployeeHoursRequest” messageType=“emp:getWeeklyHoursRequestMessage”/>

Variables process assign xsl:transform receive request response invoke request reply response 42 WSDL message WSDL message WSDL messages Variables defined using WSDL messages 42 XML schemas XML Schema elements / types Variables defined using XML schema elements or types

Basic Activities receive reply invoke Invoke a one-way or request-response operation Do a blocking wait for a matching message to arrive / send a message in reply validate assign Update the values of variables or partner links with new data Validate XML data stored in variables throw rethrow Generate a fault from inside the business process Forward a fault from inside a fault handler exit Immediately terminate execution of a business process instance compensate compensateScope Invoke compensation on all completed child scopes in default order Invoke compensation on one completed child scope wait Wait for a given time period or until a certain time has passed empty No-op instruction for a business process

process flow Contained activities are executed in parallel, partially ordered through control links sequence Contained activities are performed sequentially in lexical order while Contained activity is repeated while a predicate holds Contained activity is repeated until a predicate holds pick Block and wait for a suitable message to arrive (or time out) forN Contained activity is performed sequentially or in parallel, controlled by a specified counter variable if-elseif-else Select exactly one branch of activity from a set of choices scope Associate contained activity with its own local variables, partner links, etc., and handlers Structured Activities 2.N.1. … B C A cc1c2 … 2.N.1. … … AM2M1

Scopes Scopes provide a context which influences the execution behavior of its enclosed activities Local declarations – partner links, message exchanges, variables, correlation sets Local handlers – event handlers, fault handlers, a termination handler, and a compensation handler

PROCESS FLOW

BPEL Syntax Example Process Steps <receive partnerLink="client" portType="com:InsuranceSelectionPT" operation="SelectInsurance" variable="InsuranceRequest" createInstance="yes" /> <invoke partnerLink="insuranceA" portType="ins:ComputeInsurancePremiumPT" operation="ComputeInsurancePremium" inputVariable="InsuranceRequest" outputVariable="InsuranceAResposne" /> <invoke partnerLink="insuranceB" portType="ins:ComputeInsurancePremiumPT" operation="ComputeInsurancePremium" inputVariable="InsuranceRequest" outputVariable="InsuranceBResposne" />

BPEL Syntax Example Process Steps <case condition="bpws:getVariableData('InsuranceAResposne', 'confirmationData','/confirmationData/Amount') <= bpws:getVariableData('InsuranceBResposne', 'confirmationData','/confirmationData/Amount')">