This documentation is for WSO2 Enterprise Service Bus version 4.8.1 . View documentation for the latest release.

All docs This doc

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

This sample demonstrates the functionality of the  Transaction Mediator using a sample distributed transaction. In this sample, a record is delete deleted from one database and added to a second database. If either of the operations (deleting from the first database and adding to the other) fails, all operations will roll back, and the records will be untouchednot change.

Also, see Transaction Mediator.

Prerequisites

  • For a list of general prerequisites,

...

Building the sample

1. First, let's take a look at the synapse configuration used The XML configuration for this sample .is as follows: 

Code Block
languagehtml/xml
linenumberstrue
<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>jdbc/XADerbyDS</dsName>
                        <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>jdbc/XADerbyDS1</dsName>
                        <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>

2. The above sample configuration uses two data sources and database instances to point to the sample databases. You have to manually create these in your environment for the sample to work.

3. Start the ESB server and log into its management console UI (https://localhost:9443/carbon). In the management console, navigate to Main Menu, click Service Bus and then Source View. Next, copy and paste the above synapse configuration, which helps you explore the example scenario, to the source view  

4. Deploy the back-end service SimpleStockQuoteService, and start the Axis2 server using the instructions given in section Starting Sample Back-End ServicesThis configuration file  synapse_sample_657.xml is available in the <ESB_HOME>/repository/samples directory.

To build the sample

  1. Start the ESB with the sample 657 configuration. For instructions on starting a sample ESB configuration, see Starting the ESB with a sample configuration.
    The operation log keeps running until the server starts, which usually takes several seconds. Wait until the server has fully booted up and displays a message similar to "WSO2 Carbon started in n seconds."

  2. Start the Axis2 server. For instructions on starting the Axis2 server, see Starting the Axis2 server.

  3. Deploy the back-end service SimpleStockQuoteService. For instructions on deploying sample back-end services, see Deploying sample back-end services.

Info
titleInfor

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.

You now have a running ESB instance, databases and a back-end service deployed in your environment.

Executing the sample

We run this setup using the sample The sample client used here is the Stock Quote Client, which can operate in several modes. For information further details on this sample client , refer to section and its operation modes, see Stock Quote Client.

To execute the sample client

  • Execute the following command from the <ESB_HOME>/samples/axis2Client directory to test the successful scenario.

    Code Block
    ant stockquote -Daddurl=http://localhost:9000/services/SimpleStockQuoteService
    -Dtrpurl=http://localhost:8280/ -Dsymbol=IBM
  • Execute the following command

...

  • from the <ESB_HOME>/samples/axis2Client directory to test the failure scenario.

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

...

Analyzing the output

When you run the client to test the successful scenario, you will see that the IBM record is removed from the first database and added to the second database.

When you run the client to test the failure scenario, you will see that all operations roll back and none of the records gets are affected.