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.


{panel:title=Last tested with}
* Petals ESB 3.1
* Petals Studio 1.1.0
* Petals SE RMI 1.1.1
* Petals BC SOAP 4.0.2
* Petals Webconsole 2.0.3
* Tomcat 6.0.29
* JDK 6 update 20
* Petals SE Jsr181 1.1.2

*Added in this tutorial :*
* Petals SE EIP 2.4.3
{panel}

{info}This tutorial is based on [EIP Buffer complex use case|petalscomponents:Bufferize operations with EIP].
{info}

h2. Definition of our integration process

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.

{gliffy:space=petalscomponents|page=Bufferize operations with EIP|name=Petals RMI-EIP-JSR181}

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

*What is Agregator pattern ?*
[TODO]

*What is Splitter Pattern ?*
[TODO]

h2. Create and deploy an EIP Service Assembly

There is a tight-coupling between both EIP. Assembling them in one single SA can be a good idea (especially with EIP, which can chain lots of patterns, each requiring a different SU).
# Create a new Service Assembly.
|| Service Assembly || ||
| Name | sa-Eip-AggregatorSplitter |
# Add the two EIP Service-Units you created, and confirm.
# Fast-export the Service Assembly for Petals.
# Deploy in Petals ESB.


h2. Understand XPath expressions

*What is XPath ?*

Run this tutorial (takes \~30 min) for Xpath : [http://www.w3schools.com/XPath/default.asp|http://www.w3schools.com/XPath/default.asp]
Now try to understand the XPath expressions we used. If you use EIP later, it is essential to understand and be able to write XPath.



*EIP Agregator conditions*
# Elements which satisfy "aggregator-correlation" are aggregated
{code:lang=xml}<eip:aggregator-correlation>boolean(/*[local-name()="AddIntegers"])</eip:aggregator-correlation>{code}
Elements inside <AddIntegers> will be aggregated.

# When "test" is true, aggregated message is sent.
{code:lang=xml}<eip:test>boolean(/*[local-name()="AddIntegers"]/*[local-name()="equals"])</eip:test>{code}
When <AddIntegers> contains the <equals> element, the aggregated message is sent to the next service, and buffer cleared.


*EIP Splitter conditions*
# Elements which satisfy "test" are extracted and sent to the next service.
{code:lang=xml}<eip:test>//*[local-name()="AddIntegers"]</eip:test>{code}
<AddIntegers> elements are split and sent one by one.

h2. Test the EIP chain

# Deploy the SA containing the SU su-jsr181-MathOperations-provide.
# Deploy the SA&nbsp;sa-Eip-AggregatorSplitter.
# Send messages from webconsole, with InOut MEP (message exchange pattern).
# Send the trigger message.

{code:lang=xml|title=Message 1|theme=Default}
<AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
<integer1>1</integer1>
<integer2>2</integer2>
</AddIntegers>
{code}

{code:lang=xml|title=Response message|theme=Default}
<result xmlns="http://petals.ow2.org/petals-se-eip/aggregator">Aggregator: the content is buffered by the pattern</result>
{code}


{code:lange=xml|title=Message 2|theme=Default}
<AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
<integer1>3</integer1>
<integer2>4</integer2>
</AddIntegers>
{code}

{code:lang=xml|title=Message 3|theme=Default}
<AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
<integer1>5</integer1>
<integer2>6</integer2>
</AddIntegers>
{code}

{code:lang=xml|title=Message 4 - Trigger|theme=Default}
<AddIntegers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
<equals/>
</AddIntegers>
{code}

{code:lang=xml|title=Response message|theme=Default}
<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>
{code}

h2. More about orchestration

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

[TODO]

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.