Hi ! Today is you last day. You will create a simple process: bufferize messages, and execute all of them in one time with MathOperations. You will use EIP chains for this.

This tutorial is based on the use case: Bufferize operations with EIP.

Integration process definition

You will use Enterprise Integration Patterns (EIP, see below for explanations) to create this process :

• Several messages are sent to an EIPAggregator pattern, which bufferize all incoming messages.
• Trigger message is sent to EipAggregator.
• EipAggregator sends an aggregated message to EipSPlitter.
• EipSplitter splits the aggregated message back into multiple messages.
• EipSPlitter sends the multiple messages to the operation AddIntegers on the service MathOperations.
• MathOperations.AddIntegers processes the messages and send you the responses.

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What is EIP ?
A set of design patterns for enterprise application integration.

What is Agregator pattern ?
What is Splitter Pattern ?
Read EIP Aggregator and EIP SPlitter documentation to understand those patterns.

Configure EIP Splitter

1. Launch Petals Studio.
2. Click File > New > Service-Unit Project.
3. Select Use a Petals technical Service > EIP > Your_EIP_Version.
4. Configure Splitter Service-Unit with following configuration:

   Parameter name	Value
   JBI properties	Note: EIP does not need a WSDL
   Interface namespace:	http://test.petalslink.com
   InterfaceName:	EipSplitterInterface
   Service Namespace:	http://test.petalslink.com
   Service Name:	EipSplitter
   End-point Name:	EipSplitterEndpoint
   Project Name and Location
   Project Name:	su-EIP-EipSplitter-provide
   Chain calls (1)
   Eip:	Splitter
   Chain calls (2)
   Selected Pattern: splitter	see below for configuration

5. Click Add > Edit. It displays the window "EIP: Invoked Service 1".
6. Click Select a service.
7. Double click MathOperations implements MathOperations @ MathOperationsPort.
8. Fill the following properties for Invoked Service 1:

   Service Identifiers	Note: auto-configured
   Invocation Properties
   Operation Namespace:	http://test.petalslink.com
   Operation:	AddIntegers
   Mep:	InOut
   Routing Condition
   XPath Condition	//*[local-name()="AddIntegers"]

9. Click Ok > Next > Finish.

Configure EIP Aggregator

1. Create another New Service-Unit Project for EIP Technical Service with the following configuration:

   Parameter name	Value
   JBI propertie
   Interface Namespace:	http://test.petalslink.com
   Interface Name:	EipAggregatorInterface
   Service Namespace:	http://test.petalslink.com
   Service Name:	EipAggregator
   End-point Name:	EipAggregatorEndpoint
   Project Name and Location
   Project Name:	su-EIP-EipAggregator-provide
   Chain calls (1)
   Eip:	Aggregator
   Aggregator Correlation:	boolean(/*[local-name()="AddIntegers"])
   Service Parameters
   Service Parameters	see below for configuration

2. Click Add > Edit. It displays the window "EIP: Invoked Service 1".
3. Click Select a service.
4. Double click EipSplitter implements EipSplitterInterface @ EipSplitterEndpoint.
5. Fill the following properties for Invoked Service 1:

   Service Identifiers	Note: auto-configured
   Invocation Properties
   Operation Namespace:	http://test.petalslink.com
   Operation:	AddIntegers
   Mep:	InOut
   Routing Condition
   XPath Condition	boolean(/*[local-name()="AddIntegers"]/*[local-name()="equals"])

6. Click Ok > Next > Finish.

Create and deploy an EIP Service Assembly

Beacause EipSplitter and EipAggregator are tight-coupled, they can be packaged in one Service Assembly, without loosing felxibility. This is especially adapted with EIP, which can chain lots of EIP Service-Units.

1. Click File > New > Service Assembly Project.

   Service Assembly
   Name:	sa-Eip-AggregatorSplitter
   Artifact ID:	sa-Eip-AggregatorSplitter

2. Click Next.
3. Check su-EIP-EipSplitter-provide and su-EIP-EipAggregator-provide.
4. Click Finish.
5. Fast-export the Service Assembly for Petals.
6. Download Petals-SE-EIP.
7. Deploy Petals-SE-EIP in Petals ESB.
8. Deploy sa-Eip-AggregatorSplitter in Petals ESB.

Understand XPath expressions

What is XPath ?
Run this tutorial (takes ~30 min) for Xpath : http://www.w3schools.com/XPath/default.asp
Look at XPath expressions used in EipSplitter and EipAggregator. Try to understand them. XPath is essential to use Petals-SE-EIP.

EIP Agregator conditions

1. Elements which satisfy "aggregator-correlation" are aggregated

   <eip:aggregator-correlation>boolean(/*[local-name()="AddIntegers"])</eip:aggregator-correlation>

   Elements inside <AddIntegers> will be aggregated.

2. When "test" is true, aggregated message is sent.

   <eip:test>boolean(/*[local-name()="AddIntegers"]/*[local-name()="equals"])</eip:test>

   When <AddIntegers> contains the <equals> element, the aggregated message is sent to the next service, and buffer cleared.

EIP Splitter conditions

1. Elements which satisfy "test" are extracted and sent to the next service.

   <eip:test>//*[local-name()="AddIntegers"]</eip:test>

   <AddIntegers> elements are split and sent one by one.

Test the EIP chain

1. Check that sa-jsr181-MathOperations-provide (from last day tutorial) is deployed in Petals ESB. If not, deploy it.
2. Deploy sa-Eip-AggregatorSplitter in Petals ESB.
3. Go to Webconsole > Server: 0 > Test > Send
4. Send following messages to Endpoint EipAggregatorEndpoint, with MEP InOut:
   Message 1

   <AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
   <integer1>1</integer1>
   <integer2>2</integer2>
   </AddIntegers>
   

   Response message

   <result xmlns="http://petals.ow2.org/petals-se-eip/aggregator">Aggregator: the content is buffered by the pattern</result>
   

   Message 2

   <AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
   <integer1>3</integer1>
   <integer2>4</integer2>
   </AddIntegers>
   

   Message 3

   <AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
   <integer1>5</integer1>
   <integer2>6</integer2>
   </AddIntegers>
   

5. Send trigger message:
   Message 4 - Trigger

   <AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
   <equals/>
   </AddIntegers>
   

   Response message

   <result xmlns="http://petals.ow2.org/petals-se-eip/splitter">
   <dlwmin:AddIntegersResponse xmlns:dlwmin="http://test.petalslink.com" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
   <returnMessage xmlns="">3</returnMessage>
   </dlwmin:AddIntegersResponse>
   <dlwmin:AddIntegersResponse xmlns:dlwmin="http://test.petalslink.com" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
   <returnMessage xmlns="">7</returnMessage>
   </dlwmin:AddIntegersResponse>
   <dlwmin:AddIntegersResponse xmlns:dlwmin="http://test.petalslink.com" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
   <returnMessage xmlns="">11</returnMessage>
   </dlwmin:AddIntegersResponse>
   </result>
   

More about orchestration

Look at other EIP patterns
Simple theory exercise: how would you do in this case....?
[TODO ?]

Orchestration alternatives
You can orchestrate services in Petals with BPEL, SCA, JSR181, EIP or POJO. Read this Orchestration Whitepaper if you are interested.

Summary:

• EIP : Good performances. But complicated and a bit "dirty old way" (for example, do not use WSDL).
• BPEL: Based on XML and WSDL. Standard. Quite complicated to learn. Poorer performances.
• SCA: The simplest. Java code based on WSDL.
• POJO or JSR181: Needs advanced Java programmation.
• Custom JBI Component: Needs lot of skills. Best performances. Hard to maintain.

Finished !
Bravo, you successfully ran the Petals Getting Started Guide.

Want to know more ?

• Tell me what additional tutorial you would like.
• Ask me for a free advise on your project architecture. I will pass it to our architects so they can have a look. This might give you new insights.
• Trainings gives advanced knowledge on Petals ESB. They talk more about SOA, and real project problems.

For all this, just contact me !
mathieu.lebreton@petalslink.com