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