This is second of the series Enterprise Integration Patterns (EIP) with OpenESB where we will cover Enterprise Integration Patterns using OpenESB.

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According to Enterprise Integration Patterns,

The Dynamic Router is a Router that can self-configure based on special configuration messages from participating destinations.

We can realize this pattern in OpenESB using Dynamic Addressing which uses WS-Addressing to dynamically determine the service location at runtime.

To check this in action we need 3 Projects –

• EJB Module implementing the Web Service – you can use any WSDL based web service, not necessary to use EJB.
• BPEL – This will contain the actual code that determines the endpoint at runtime.
• JBI / CASA – This is a composite application necessary to deploy the BPEL.

Step 1 – We create a web service with 2 operations – addition and subtraction. Both operations take 2 numbers as input and return result.
Here’s the xsd –

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    targetNamespace="http://xml.aurorite.com/schema/numberBase"
    xmlns:tns="http://xml.aurorite.com/schema/numberBase"
    elementFormDefault="qualified">

    <xsd:element name="NumbersAdditionRequest" type="tns:AdditionType"/>
    <xsd:element name="NumbersAdditionResponse" type="tns:OperationResultType"/>
    <xsd:element name="NumbersSubtractionRequest" type="tns:SubtractionType"/>
    <xsd:element name="NumbersSubtractionResponse" type="tns:OperationResultType"/>

    <xsd:complexType name="AdditionType">
        <xsd:sequence>
            <xsd:element name="number1" type="xsd:int"/>
            <xsd:element name="number2" type="xsd:int"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:complexType name="SubtractionType">
        <xsd:sequence>
            <xsd:element name="number1" type="xsd:int"/>
            <xsd:element name="number2" type="xsd:int"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:complexType name="OperationResultType">
        <xsd:sequence>
            <xsd:element name="result" type="xsd:int"/>
            <xsd:element name="processor" type="xsd:string"/>
        </xsd:sequence>
    </xsd:complexType>
</xsd:schema>

and here’s the wsdl –

<?xml version="1.0" encoding="UTF-8"?>
<definitions name="NumbersOperations"
    targetNamespace="http://websvcs.aurorite.com/wsdl/NumberOperationSvcs/NumbersOperations"
    xmlns="http://schemas.xmlsoap.org/wsdl/"
    xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
    xmlns:tns="http://websvcs.aurorite.com/wsdl/NumberOperationSvcs/NumbersOperations"
    xmlns:ns="http://xml.aurorite.com/schema/numberBase"
    xmlns:plnk="http://docs.oasis-open.org/wsbpel/2.0/plnktype"
    xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/">
    <types>
        <xsd:schema targetNamespace="http://websvcs.aurorite.com/wsdl/NumberOperationSvcs/NumbersOperations">
            <xsd:import namespace="http://xml.aurorite.com/schema/numberBase" schemaLocation="numberBase.xsd"/>
        </xsd:schema>
    </types>
    <message name="additionRequest">
        <part name="part1" element="ns:NumbersAdditionRequest"/>
    </message>
    <message name="additionResponse">
        <part name="part1" element="ns:NumbersAdditionResponse"/>
    </message>
    <message name="subtractionRequest">
        <part name="part1" element="ns:NumbersSubtractionRequest"/>
    </message>
    <message name="subtractionResponse">
        <part name="part1" element="ns:NumbersSubtractionResponse"/>
    </message>
    <portType name="NumbersOperationsPortType">
        <operation name="addition">
            <input name="input1" message="tns:additionRequest"/>
            <output name="output1" message="tns:additionResponse"/>
        </operation>
        <operation name="subtraction">
            <input name="input2" message="tns:subtractionRequest"/>
            <output name="output2" message="tns:subtractionResponse"/>
        </operation>
    </portType>
    <binding name="NumbersOperationsBinding" type="tns:NumbersOperationsPortType">
        <soap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
        <operation name="addition">
            <soap:operation/>
            <input name="input1">
                <soap:body use="literal"/>
            </input>
            <output name="output1">
                <soap:body use="literal"/>
            </output>
        </operation>
        <operation name="subtraction">
            <soap:operation/>
            <input name="input2">
                <soap:body use="literal"/>
            </input>
            <output name="output2">
                <soap:body use="literal"/>
            </output>
        </operation>
    </binding>
    <service name="NumbersOperationsService">
        <port name="NumbersOperationsPort" binding="tns:NumbersOperationsBinding">
            <soap:address location="http://localhost:8080/NumbersOperationsService/NumberService"/>
        </port>
    </service>
    <plnk:partnerLinkType name="NumbersOperations">
        <!-- A partner link type is automatically generated when a new port type is added. Partner link types are used by BPEL processes. 
In a BPEL process, a partner link represents the interaction between the BPEL process and a partner service. Each partner link is associated with a partner link type.
A partner link type characterizes the conversational relationship between two services. The partner link type can have one or two roles.-->
        <plnk:role name="NumbersOperationsPortTypeRole" portType="tns:NumbersOperationsPortType"/>
    </plnk:partnerLinkType>
</definitions>

Here is the implementation of the webservice operations –

@WebService(serviceName = "NumbersOperationsService", portName = "NumbersOperationsPort", endpointInterface = "com.aurorite.websvcs.wsdl.numberoperationsvcs.numbersoperations.NumbersOperationsPortType", targetNamespace = "http://websvcs.aurorite.com/wsdl/NumberOperationSvcs/NumbersOperations", wsdlLocation = "META-INF/wsdl/NumberService/NumbersOperations.wsdl")
@Stateless
public class NumberService {

    Logger logger = Logger.getLogger("soa.aurorite.com.NumberService");

    public com.aurorite.xml.schema.numberbase.OperationResultType addition(com.aurorite.xml.schema.numberbase.AdditionType part1) throws UnknownHostException {
        logger.info("Running this service at " + InetAddress.getLocalHost().getHostName() + " on port 8080");
        com.aurorite.xml.schema.numberbase.OperationResultType result = new com.aurorite.xml.schema.numberbase.OperationResultType();
        result.setProcessor(InetAddress.getLocalHost().getHostName());
        try {
            result.setResult(part1.getNumber1() + part1.getNumber2());
        } catch (Exception e){
            result.setResult(0);
        }

        return result;
        //throw new UnsupportedOperationException("Not implemented yet.");
    }

    public com.aurorite.xml.schema.numberbase.OperationResultType subtraction(com.aurorite.xml.schema.numberbase.SubtractionType part1) throws UnknownHostException {
        logger.info("Running this service at " + InetAddress.getLocalHost().getHostName() + " on port 8080");
        com.aurorite.xml.schema.numberbase.OperationResultType result = new com.aurorite.xml.schema.numberbase.OperationResultType();
        result.setProcessor(InetAddress.getLocalHost().getHostName());
        try {
            result.setResult(part1.getNumber1() - part1.getNumber2());
        } catch (Exception e){
            result.setResult(0);
        }
        return result;
        //throw new UnsupportedOperationException("Not implemented yet.");
    }

}

Note that I’m returning the machine name in the response. This’ll help us to determine who actually processed a particular operation.

Now to the BPEL. We’ll create a simple process looking like this –

In the BPEL, we add these 2 namespace references –

xmlns:sref="http://docs.oasis-open.org/wsbpel/2.0/serviceref" 
xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/08/addressing"
    <import namespace="http://docs.oasis-open.org/wsbpel/2.0/serviceref" location="ws-bpel_serviceref.xsd" importType="http://www.w3.org/2001/XMLSchema"/>
    <import namespace="http://schemas.xmlsoap.org/ws/2004/08/addressing" location="addressing.xsd" importType="http://www.w3.org/2001/XMLSchema"/>

And now the most important part – Adding the Service Endpoint Reference

<assign name="assign_endpoint">
    <copy>
                        <!--<from>ns2:doXslTransform('urn:stylesheets:wrap2serviceref.xsl', $EPRVariable.eprValue)</from>-->
        <from>
            <literal>
                <sref:service-ref>
                    <wsa:EndpointReference>
                        <wsa:Address>http://machine2:8080/NumbersOperationsService/NumberService</wsa:Address>
                        <wsa:ServiceName PortName="NumbersOperationsPort"
                                        xmlns:serv="http://websvcs.aurorite.com/wsdl/NumberOperationSvcs/NumbersOperations">serv:NumbersOperationsService
                        </wsa:ServiceName>
                    </wsa:EndpointReference>
                </sref:service-ref>
            </literal>
        </from>
        <to partnerLink="NumberService"/>
    </copy>
</assign>

The portname and Service name must match to the ones in target service.

This is first of the series Enterprise Integration Patterns with OpenESB where we will cover Enterprise Integration Patterns using OpenESB.

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According to Enterprise Integration Patterns,

The Content-Based Router examines the message content and routes the message onto a different channel based on data contained in the message. The routing can be based on a number of criteria such as existence of fields, specific field values etc. When implementing a Content-Based Router, special caution should be taken to make the routing function easy to maintain as the router can become a point of frequent maintenance. In more sophisticated integration scenarios, the Content-Based Router can take on the form of a configurable rules engine that computes the destination channel based on a set of configurable rules.

It can be achieved in OpenESB using “If” component.

In this example it simply checks for the value in “num:operation” element.

<soapenv:Envelope xsi:schemaLocation="http://schemas.xmlsoap.org/soap/envelope/ http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:num="http://xml.aurorite.com/schema/NumberOperationSchema">
  <soapenv:Body>
    <num:OperationRequest>
      <num:operation>ADDITION</num:operation>
      <num:data>
        <num:number1>20</num:number1>
        <num:number2>30</num:number2>
      </num:data>
    </num:OperationRequest>
  </soapenv:Body>
</soapenv:Envelope>