Transaction is a fundamental concept behind the implementation of reliable distributed applications. This mechanism ensures that all transaction participants receive the same result.

In essence, a transaction is characterized by the ACID properties.

To control the operation and result of an application, a web service environment needs to provide the same coordinated behavior that is provided by the traditional transaction mechanism. It also requires a functionality that coordinates the processing of results from multiple services which requires a more flexible type of transaction.

The following are the transaction specifications supported by JEUS 8 web services.

These transaction specifications provide a WSDL definition for such coordinated behavior.

A web service transaction for a server application is defined in a WSDL or Java class.

<wsat200410:ATAssertion xmlns:ns1="http://schemas.xmlsoap.org/ws/2002/12/policy" />

<?xml version="1.0" encoding="UTF-8"?>
<definitions name="AddNumbersService" targetNamespace="http://server.fromwsdl/"
    xmlns:tns="http://server.fromwsdl/" xmlns="http://schemas.xmlsoap.org/wsdl/"
    xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/
    oasis-200401-wss-wssecurity-utility-1.0.xsd"
    xmlns:wsp="http://www.w3.org/ns/ws-policy"
    xmlns:wsp1_2="http://schemas.xmlsoap.org/ws/2004/09/policy"
    xmlns:wsam="http://www.w3.org/2007/05/addressing/metadata"
    xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <wsp:Policy xmlns:wsat200410="http://schemas.xmlsoap.org/ws/2004/10/wsat"
        wsu:Id="AddNumbersPortBinding_addNumbers_WSAT_Policy" wsp:Name="">
        <wsat200410:ATAssertion 
            xmlns:ns1="http://schemas.xmlsoap.org/ws/2002/12/policy"
            wsp:Optional="true" ns1:Optional="true" />
    </wsp:Policy>
    <types>...</types>    
    <message>...</message>    
    <portType>...</portType>
    
    <binding name="AddNumbersPortBinding" type="tns:AddNumbers">
       <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document" />
       <operation name="addNumbers">
        <wsp:PolicyReference URI="#AddNumbersPortBinding_addNumbers_WSAT_Policy" />
         <soap:operation soapAction="addNumbers" />
         <input>
           <wsp:PolicyReference URI="#AddNumbersPortBinding_addNumbers_WSAT_Policy" />
             <soap:body use="literal" />
         </input>
         <output>
           <wsp:PolicyReference URI="#AddNumbersPortBinding_addNumbers_WSAT_Policy" />
             <soap:body use="literal" />
         </output>
       </operation>
    </binding>
    <service>...</service>
<definitions>

@com.sun.xml.ws.api.tx.at.Transactional(version=com.sun.xml.ws.api.tx.at.Transactional.Version.WSAT10)

@WebService
@com.sun.xml.ws.api.tx.at.Transactional(
       version=com.sun.xml.ws.api.tx.at.Transactional.Version.WSAT10)
public class AddNumbersImpl {
    ...
}

There are no additional settings for web service transaction on the client side. The client applications that invoke the web service automatically provides a web service transaction environment at runtime by remotely reading the web service transaction policy from the WSDL.

To use a web service transaction, a coordinator service that tunes the transaction activities between participants must be deployed. A coordinator service is required for both server and client applications. Only one coordinator service must be deployed when a web service and a web service client are running on the same server.

The 'wstx-services.ear' file for coordinator service is in the following path.

JEUS_HOME/lib/systemapps

Web service transaction implementation using a Java class is the same as the implementation of other basic JEUS web services, except that it requires adding the @com.sun.xml.ws.api.tx.at.Transactional annotation.

Java Transaction API (JTA) is used to implement a web service transaction on a web service client.

InitialContext  ctx = new InitialContext();
UserTransaction utx = (UserTransaction) ctx.lookup("java:comp/UserTransaction");

AddNumbersImplService service = new AddNumbersImplService();
AddNumbersImpl port = service.getAddNumbersImplPort();
      
utx.begin();

int result = port.addNumbers(number1, number2);
        
utx.commit();