Generate BPEL for Oracle workflow engine

Written Date: September 4, 2006

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BPEL stand for Business Process Execution Language, which is used to describe business process as well as executing the process. This topic is going to introduce the major steps of generating BPEL for Oracle workflow engine.

Drawing BPEL Business Process Diagram

As the name implies, BPEL Business Process Diagram is a Business Process Diagram for BPEL (Business Process Execution Language). It is used to model business process and make it executable.

Creating Participant for Pool

According to the specification of BPEL, each BEPL is described by WSDL. Within BPEL Business Process Diagram, there a something similar Participant of Pool. The below steps demonstrate how to create Participant for Pool by using template.

Open or create Business Process Diagram.

Open Specification of Pool.

Create Participant using template.

Click OK several times to apply and close all dialogs.

Create option	Creation result
Create Participant...	Empty Participant
Create asynchronous Participant...	Participant of asynchronous template
Create synchronous Participant...	Participant of synchronous template

Asynchronous Participant

When using asynchronous Participant, the BPEL process will become asynchronous at runtime. As implied by the name, interaction of asynchronous process may not reply immediately. Therefore, another operation should be defined for the callback purpose. In our asynchronous template, two sets of partnerLinkType, portType and operation are included, which to be used for caller and callback.

Synchronous Participant

Opposite to asynchronous Participant, synchronous Participant will cause BPEL process become synchronous at runtime. Any interaction of synchronous Participant must reply immediately. Therefore, only one operation is required and the synchronous template is including only one set of partnerLinkType, portType and operation.

Creating and setting Partner Link

Partner Link is a reference of Web Service used within BPEL. In BPEL Business Process Diagram, Pool is used to define Partner Link.

Open Specification of Pool.

Normally, Pool with Partner Link will be set as black box.

Create Partner Link.

Since Partner Link is separated from Pool, name of Partner Link should be maintained manually.

Participant of Partner Link is used to describe which Web Service it refers to.

Partner Link Type of Partner Link represents the interaction of BPEL and Web Service.

My Role and Partner Role is used for identifying responsibility of interaction. In synchronous process, only one role is required because it is a single direction invocation. In asynchronous process, two roles are required which describe caller role and callback role.

Role	Description
My Role	The role of current business process.
Partner Role	The role of opposite side such as client application or Web Service.

Setting BPEL Properties

For executing the business process, some related properties are required to set. Basic properties are described in the example below.

Simple Example

In the example, the Business Process will start by receiving a message. Then it will make some modification to the message. Finally, the modified message will return back.

Draw Business Process.

Start by receive a message.

I.	Open Specification of Task.


II.	Check Instantiate if message will create a process instance. Since process will start when message is received, Instantiate should be checked.


III.	Open Specification of Task Type.


IV.	Select Partner Link of receiving message. Since message is from other to current process, the Partner Link should be "Client" which is the Web Service interface of current process.


V.	Select Operation to be invoked by other.


VI.	Select the corresponding Varaible. Since the Variable does not exist, create one for it.


VII.	Select the corresponding Message. Select Process1_RequestMessage since the Operation required it as input message.


VIII.	Click OK several times to apply and close all dialog boxes.

Modify the received message.

I.	Open Specification of Task.


II.	Create Assignment.


III.	Create From.


IV.	Create To.


V.	Select Varaible to be copied from.


VI.	Select Part of Variable to be copied from.


VII.	Input Query of the value to be copied from.


VIII.	Create To Variable. Create a Variable for storing modified message and return back.


IX.	Select the corresponding Message. Select Process1_ResponseMessage since the Operation for return required it as input message.


X.	Select Part of Variable to be copied to.


XI.	Input Query of the value to be copied to.


XII.	Click OK several times to apply and close all dialog boxes.

Return modified message back.

I.	Open Specification of Task.


II.	Open Specification of Task Type.


III.	Check Reply if process is synchronous. Since process is asynchronous, it should not be checked.


IV.	Select Partner Link of return message.


V.	Select Operation to be used for return.


VI.	Select the corresponding Varaible.


VII.	Click OK several times to apply and close all dialog boxes.

Properties Reference

The tables below show BPEL related properties with description.

Business Process Diagram

Location	Property	Description	Dependence
General:Tab	Participant	Web Service interface of BPEL
BPEL:Tab → Variable:Tab		List of global Variable
BPEL:Tab → Correlation Sets:Tab		List of global Correlation Set

Variable

Location	Property	Description	Dependence
BPEL:Tab	Message	Message type of Variable

Correlation Set

Location	Property	Description	Dependence
BPEL:Tab →Properties:Tab		List of selected Property

Unspecified Task

Location	Property	Description	Dependence
Assignments:Tab		List of Copy Rule

Assignment (Copy Rule)

Location	Property	Description	Dependence
BPEL:Tab	From	From of Copy Rule
Same as above	To	To of Copy Rule

From Variable, To Variable

Location	Property	Description	Dependence
BPEL:Tab	Variable	Variable to be copied
Same as above	Part	Copy Part of Variable	Variable
Same as above	Query	Query of copy value

From Expression

Location	Property	Description	Dependence
BPEL:Tab	Expression	Expression of copy value

From Property, To Property

Location	Property	Description	Dependence
BPEL:Tab	Property	Property to be copied

From Partner Link

Location	Property	Description	Dependence
BPEL:Tab	Partner Link	Target Partner Link
Same as above	End Point Reference	Role of Partner Link

To Partner Link

Location	Property	Description	Dependence
BPEL:Tab	Partner Link	Target Partner Link

Receive Task

Location	Property	Description	Dependence
General:Tab → Type:Specification - → BPEL:Tab - - → General:Tab	Partner Link	Target Partner Link
Same as above	Operation	Operation to be invoked	Partner Link
Same as above	Variable	Variable for receive message	Operation
General:Tab → Type:Specification - → BPEL:Tab - - → Correlations:Tab		List of Correlations

Correlation

Location	Property	Description	Dependence
BPEL:Tab	Initiate	Is initiate
Same as above	Set	Correlation Set used
Same as above	Pattern	Pattern of Correlation	Task Type Intermediate Event Type Reply

Send Task

Location	Property	Description	Dependence
General:Tab → Type:Specification - → BPEL:Tab - - → General:Tab	Reply	Act as Reply or Invoke
Same as above	Partner Link	Target Partner Link
Same as above	Operation	Operation to be invoked	Partner Link Reply
Same as above	Variable	Variable to be used	Operation Reply
General:Tab → Type:Specification - → BPEL:Tab - - → Correlations:Tab		List of Correlations

Service, User, Script, Manual Task

Location	Property	Description	Dependence
General:Tab → Type:Specification - → BPEL:Tab - - → General:Tab	Partner Link	Target Partner Link
Same as above	Operation	Operation to be invoked	Partner Link
Same as above	Input Variable	Variable for send message	Operation
Same as above	Output Variable	Variable for receive message	Operation
General:Tab → Type:Specification - → BPEL:Tab - - → Correlations:Tab		Correlations

Timer Intermediate Event

Location	Property	Description	Dependence
General:Tab → Trigger:Specification - → BPEL:Tab	For	Time duration of executing time
Same as above	For's Expression	Expression of time duration of executing time
Same as above	Until	Fixed time
Same as above	Until's Expression	Expression of fixed time

Error Intermediate Event

Location	Property	Description	Dependence
General:Tab → Trigger:Specification - → BPEL:Tab	Fault	Target Fault type
Same as above	Fault Variable	Variable to be used

Compensation Intermediate Event

Location	Property	Description	Dependence
General:Tab → Trigger:Specification - → BPEL:Tab	Scope	Scope to be compensated

Message, Rule, Link Intermediate Event

Location	Property	Description	Dependence
General:Tab → Type:Specification - → BPEL:Tab - - → General:Tab	Reply	Act as Reply or Invoke
Same as above	Partner Link	Target Partner Link
Same as above	Operation	Operation to be invoked	Partner Link Reply
Same as above	Variable	Variable to be used	Operation Reply
General:Tab → Type:Specification - → BPEL:Tab - - → Correlations:Tab		List of Correlations

Embedded Sub Process

Location	Property	Description	Dependence
General:Tab → Type:Specification - → BPEL:Tab - - → Variable:Tab		List of local Variable
General:Tab → Type:Specification - → BPEL:Tab - - → Correlation Sets:Tab		List of local Correlation Set

Data Gateway

Location	Property	Description	Dependence
General:Tab → Type:Specification - → BPEL:Tab	While	Is while or do-while

Event Gateway

Location	Property	Description	Dependence
General:Tab → Type:Specification - → General:Tab	Initiate	Is initiate

Generating Oracle BPEL

Since Oracle BPEL is one of the supported target server, generating BPEL for Oracle is simple. However, as only basic validation is provided, an invalid BPEL may also be generated and it may fail at deployment generation.

1.	Open Export Dialog.


2.	Select Output Directory.


3.	Select Target Server.


4.	Configure Target Server.


	I.	Select Oracle BPEL Home.


	II.	Input Partner Link Map.


5.	Check Auto Overwrite if overwrite existing files.


6.	Start Export.


7.	Wait until export finished.




8.	Review Export Result. Double click on the list item may open a dialog with file content.


9.	Debug Feature. Since it is not easy to debug a diagram with message only, an export details is provided.




	Export Details

	Export Details is the actual steps of exporting BPEL for debugging usage. In exporting BPEL, there are six major procedures. Each procedure depends on its previous procedure and will be executed one by one. Any errors within the procedure will be stored, and then try to continue the procedure. If procedure has error occurred, the next procedure will not be executed and the whole progress will be canceled.

	The Export Trace dialog box is used to display the steps of each procedure. In other words, it show the diagram?s execution sequence of each procedure. With the Export Trace dialog box, it is possible to show details by double-clicking on a list item. However, some items are not possible to visualize. Therefore, double-clicking on those items will have no effect.

Deploying and testing BPEL

After generated Oracle BPEL, a BPEL suitcase bpel_*.jar will be created by bpelc at the selected output directory. If file does not exist, there must be problem with the diagram. Please refer to the export details and try to fix it.

	Deploy BPEL into Oracle

	1.	Open browser and login to Oracle BPEL console.

	2.	Click Deploy New Process on Dashboard.


	3.	Select created BPEL suitcase and click deploy.




	4.	Click deployed process.


	5.	Input value for message.


	6.	Create process instance by sending message.


	7.	View the flow of instance.


	8.	View returned message.

Samples

Click on the link below to download:
• The VP project of the Simple Example.
		simple_example.zip
• The exported BPEL suitcase.
		bpel_process1_v2006_07_28_41487.jar
• The BPEL file exported from Simple Example.vpp.
		process1.bpel
• The WSDL file exported from Simple Example.vpp.
		process1_participant.wsdl
• The BPEL suitcase descriptor file exported from Simple Example.vpp.
		bpel.xml

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Comments (2)

written by BP-VANewUser on April 14, 2010

Hi,
In the latest version of BP-VA I couldn't locate these feature. When 'Generate BPEL' option under utilities is used only an error message like 'BPEL Generation Failed' is given. No reasons for the failures are given.

Also could not locate a way to generate the WSDL of the external web service (after adding partner links) through BP-VA.

Are these features unsupported in the new version (Simulacian) or not available in the trial download.

Thanks.

written by ? on April 15, 2010

Please right click the diagram, Select "BPEL" under the "Diagram Type" menu item

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