Sample 657: Distributed Transaction Management

Introduction

This sample demonstrates the use of the Transaction Mediator using a sample distributed transaction.

Prerequisites

Refer to Prerequisites section in ESB Samples Setup page.

Building the Sample

1. Start the ESB with the synapse configuration numbered 267, by running the following command.

wso2esb-samples.sh -sn 267
wso2esb-samples.bat -sn 267

For more information on starting ESB with different synapse configurations, refer to section Starting Sample ESB Configurations.

2. A message should appear in the command or text Linux console stating the server started successfully.

3. The synapse configuration for the ESB used for this sample is provided in <ESB_HOME>/repository/samples/synapse_sample_267.xml as shown below:

<definitions xmlns="http://ws.apache.org/ns/synapse"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://ws.apache.org/ns/synapse http://synapse.apache.org/ns/2010/04/configuration/synapse_config.xsd">
    <sequence name="myFaultHandler">
        <log level="custom">
            <property name="text" value="** Rollback Transaction**"/>
        </log>
        <transaction action="rollback"/>
        <send/>
    </sequence>
    <sequence name="main" onError="myFaultHandler">
        <in>
            <send>
                <endpoint>
                    <address uri="http://localhost:9000/services/SimpleStockQuoteService"/>
                </endpoint>
            </send>
        </in>
        <out>
            <transaction action="new"/>
            <log level="custom">
                <property name="text" value="** Reporting to the Database esbdb**"/>
            </log>
            <dbreport useTransaction="true" xmlns="http://ws.apache.org/ns/synapse">
                <connection>
                    <pool>
                        <dsName>java:jdbc/XADerbyDS</dsName>
                        <icClass>org.jnp.interfaces.NamingContextFactory</icClass>
                        <url>localhost:1099</url>
                        <user>synapse</user>
                        <password>synapse</password>
                    </pool>
                </connection>
                <statement>
                    <sql>delete from company where name =?</sql>
                    <parameter expression="//m0:return/m1:symbol/child::text()"
                               xmlns:m0="http://services.samples"
                               xmlns:m1="http://services.samples/xsd"
                               type="VARCHAR"/>
                </statement>
            </dbreport>
            <log level="custom">
                <property name="text" value="** Reporting to the Database esbdb1**"/>
            </log>
            <dbreport useTransaction="true" xmlns="http://ws.apache.org/ns/synapse">
                <connection>
                    <pool>
                        <dsName>java:jdbc/XADerbyDS1</dsName>
                        <icClass>org.jnp.interfaces.NamingContextFactory</icClass>
                        <url>localhost:1099</url>
                        <user>synapse</user>
                        <password>synapse</password>
                    </pool>
                </connection>
                <statement>
                    <sql>INSERT into company values ('IBM','c4',12.0)</sql>
                </statement>
            </dbreport>
            <transaction action="commit"/>
            <send/>
        </out>
    </sequence>
</definitions>

4. Deploy the back-end service SimpleStockQuoteService and start the Axis2 server using the instructions given in section Starting Sample Back-End Services.

Infor

WSO2 ESB comes with a default JTA transaction manager (Atomikos), which allows you to run distributed transactions without deploying the ESB on an external application server.

5. Define two XA datasources for above two datasources.

3. Create two database instances, this will be used by the two XA data sources.

Tip

Refer the "Sample Setup Guide" to see how you can set up the derby database server.

In this sample a record is delete from one database and it is added into the second database. If either of the operations(deleting from the first database and adding into the second database) fails everything will be roll backed. The records will be untouched.

Invoke the client as follows.

ant stockquote -Daddurl=http://localhost:9000/services/SimpleStockQuoteService -Dtrpurl=http://localhost:8280/ -Dsymbol=SUN/