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• For a list of general prerequisites, see Setting Up the ESB Samples.
• The sample configuration uses two datasources and database instances to point to the sample databases. You have to manually create these in your environment for the sample to work.

  • Setup two distributed Derby databases  esbdb and  esbdb1.  For instructions on setting up the Derby databases,  see Setting up Remote Derby.

  • Create a table in esbdb by executing the following statement.

    Code Block
    SQL SQL
    CREATE table company(name varchar(10) primary key, id varchar(10), price double);

  • Create a table in esbdb1 by executing the following statement.

    Code Block
    SQL SQL
    CREATE table company(name varchar(10) primary key, id varchar(10), price double);

  • Insert records into the two tables that you created by executing the following statements.

    To insert records into the table in esbdb

    Code Block
    SQL SQL
    INSERT into company values ('IBM','c1',0.0); INSERT into company values ('SUN','c2',0.0);

    To insert records into the table in esbdb1

    Code Block
    SQL SQL
    INSERT into company values ('SUN','c2',0.0); INSERT into company values ('MSFT','c3',0.0);

    Info
    title Note
    When inserting records into the tables, the order of the record matters.

  • Add the required datasource via the Management Console or create datasource declarations for the distributed databases In the master-datasources.xml file. For information on how you can add datasources via the management console, see Adding Datasources.  To create datasource declarations In the  master-datasources.xml  file, add the following code segments in the  master-datasources.xml  file located in the < ESB_HOME>/repository/conf/datasources  directory, create datasource declarations for the distributed databases, ensuring  ensuring that the datasource file names are  *-xa-ds.xml :
    Datasource1: esb-derby-xa-ds.xml

    Code Block
    XML XML
    <datasources> <xa-datasource> <jndi-name>jdbc/XADerbyDS</jndi-name> <isSameRM-override-value>false</isSameRM-override-value> <xa-datasource-class>org.apache.derby.jdbc.ClientXADataSource</xa-datasource-class> <xa-datasource-property name="portNumber">1527</xa-datasource-property> <xa-datasource-property name="DatabaseName">esbdb</xa-datasource-property> <xa-datasource-property name="Useruser">esb</xa-datasource-property> <xa-datasource-property name="Passwordpassword">esb</xa-datasource-property> <metadata> <type-mapping>Derby</type-mapping> </metadata> </xa-datasource> </datasources>

    Datasource2: esb-derby1-xa-ds.xml

    Code Block
    XML XML
    <datasources> <xa-datasource> <jndi-name>jdbc/XADerbyDS1</jndi-name> <isSameRM-override-value>false</isSameRM-override-value> <xa-datasource-class>org.apache.derby.jdbc.ClientXADataSource</xa-datasource-class> <xa-datasource-property name="portNumber">1527</xa-datasource-property> <xa-datasource-property name="DatabaseName">esbdb1</xa-datasource-property> <xa-datasource-property name="Useruser">esb</xa-datasource-property> <xa-datasource-property name="Passwordpassword">esb</xa-datasource-property> <metadata> <type-mapping>Derby</type-mapping> </metadata> </xa-datasource> </datasources>

Building the sample

The XML configuration for this sample is as follows: 

<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>esb</user>
                        <password>esb</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>esb</user>
                        <password>esb</password>
                    </pool>
                </connection>
                <statement>
                    <sql>INSERT into company values ('IBM','c4',12.0)</sql>
                </statement>
            </dbreport>
            <transaction action="commit"/>
            <send/>
        </out>
    </sequence>
</definitions>

This 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 sample configuration given above.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.

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When you run the client to test the failure scenario, you will see that a record is neither deleted from the first database nor added into the second database. That is because executing because executing the command attempts to add an already existing record again to the second database, which results in the fault sequence being executed. Therefore, an exception raised for duplicate entries and results in an entire transaction rollback.