Integrating BTM with iBatis

iBatis can be integrated straight with any JTA transaction manager. These instructions have been verified against BTM 2.0.1.

Contents

JTA datasources

iBatis cannot directly create a BTM PoolingDataSource. You will have to create them yourself (either via the API or the Resource Loader) and make sure they are bound to a JNDI server.

Setting up the BTM JNDI server

You have to bind the datasources and the transaction manager to some JNDI server. You can use any one you wish, but BTM 2.x.x ships with one you might find more convenient to use.

It is very easy to use it in a standalone J2SE application. Just create a jndi.properties file at the root of your classpath. It should only contain this line:

java.naming.factory.initial=bitronix.tm.jndi.BitronixInitialContextFactory

You can now just create a InitialContext with the no-args constructor to have access to it.

API way: Creating the datasources

As you can expect, you will need to create one PoolingDataSource per database. Say that you want to use two Embedded Derby databases, and configure them via the BTM API. Here is what your code would look like:

PoolingDataSource ds1 = new PoolingDataSource();
ds1.setUniqueName("jdbc/testDS1");
ds1.setClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
ds1.setMaxPoolSize(3);
ds1.getDriverProperties().put("databaseName", "users1");
ds1.init();

PoolingDataSource ds2 = new PoolingDataSource();
ds2.setUniqueName("jdbc/testDS2");
ds2.setClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
ds2.setMaxPoolSize(3);
ds2.getDriverProperties().put("databaseName", "users2");
ds2.init();

Finally, here is the code to bind the datasources:

Context ctx = new InitialContext();
ctx.createSubcontext("jdbc");
ctx.rebind("jdbc/testDS1", ds1);
ctx.rebind("jdbc/testDS2", ds2);
ctx.close();

Resource Loader way: Creating the datasources

You can use BTM's Resource Loader instead of the BTM API. It is usually a good idea when you want to create a fully standalone application as you can get rid of the datasources creation, JNDI binding and shutdown code.

Create a datasources.properties file in the current directory containing these properties:

resource.ds1.className=org.apache.derby.jdbc.EmbeddedXADataSource
resource.ds1.uniqueName=jdbc/testDS1
resource.ds1.maxPoolSize=3
resource.ds1.driverProperties.databaseName=users1

resource.ds2.className=org.apache.derby.jdbc.EmbeddedXADataSource
resource.ds2.uniqueName=jdbc/testDS2
resource.ds2.maxPoolSize=3
resource.ds2.driverProperties.databaseName=users2

In your application code, you will have to configure BTM to use the resource loader:

TransactionManagerServices.getConfiguration().setResourceConfigurationFilename("./datasources.properties");
userTransaction = TransactionManagerServices.getTransactionManager();

This has the exact same behavior as creating the PoolingDataSource objects and binding them to JNDI yourself. It is just more convenient.

iBatis SqlMapClients

You need to configure exactly one SqlMapClient per datasource.

Datasource JNDI location

You have to tell iBatis where to get the BTM datasource via JNDI. Add a DataSource property to the dataSource tag and set its value to the JNDI location of your datasource:

<dataSource type="JNDI">
  <property name="DataSource" value="jdbc/testDS1"/>
</dataSource>

Transaction Manager JNDI location

You have to set transactionManager tag's type attribute to JTA and wrap the dataSource tag in it.

  <transactionManager type="JTA" >
    <property name="UserTransaction" value="UserTransaction"/>
    <dataSource type="JNDI">
      <property name="DataSource" value="jdbc/testDS1"/>
    </dataSource>
  </transactionManager>

SqlMapConfig XML configuration files

Here is what the SqlMapConfig1.xml file will look like for the first datasource.

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE sqlMapConfig      
    PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"      
    "http://ibatis.apache.org/dtd/sql-map-config-2.dtd">

<sqlMapConfig>

  <transactionManager type="JTA" >
    <property name="UserTransaction" value="UserTransaction"/>
    <dataSource type="JNDI">
      <property name="DataSource" value="jdbc/testDS1"/>
    </dataSource>
  </transactionManager>
  
  <sqlMap resource="bitronix/examples/ibatis/entities/User.xml"/>

</sqlMapConfig>

And here is the SqlMapConfig2.xml for the second datasource:

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE sqlMapConfig      
    PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"      
    "http://ibatis.apache.org/dtd/sql-map-config-2.dtd">

<sqlMapConfig>

  <transactionManager type="JTA" >
    <property name="UserTransaction" value="UserTransaction"/>
    <dataSource type="JNDI">
      <property name="DataSource" value="jdbc/testDS2"/>
    </dataSource>
  </transactionManager>
  
  <sqlMap resource="bitronix/examples/ibatis/entities/User.xml"/>

</sqlMapConfig>

End result

Now that iBatis and BTM are properly configured, you can simply use the JTA and iBatis APIs in your application.

Application code

Here is what your code will look like when you want to update the content of both databases atomically:

for (int i=0; i<10 ;i++) {
    System.out.println("Iteration #" + (i+1));
    userTransaction.setTransactionTimeout(60);
    userTransaction.begin();
    
    try {
        System.out.println("*** DB1 ***");
        persistUser(smc1, "user");
        listUsers(smc1);
    
        System.out.println("*** DB2 ***");
        persistUser(smc2, "user");
        listUsers(smc2);
    
        userTransaction.commit();
    }
    catch (Exception ex) {
        ex.printStackTrace();
        userTransaction.rollback();
    }
}

Say that persistUser() creates a new user, in no way will a user be created in one database and not in the other.

Download

You can download a sample runnable application putting these explanations in practice. It contains all the code that has been skipped for clarity in this page. Both the API and Resource Loader ways are implemented so you can try both and see which one you prefer.

You can download this demo here: iBatisBTM2x.zip.

There is an ant build.xml file included as well as a the necessary batch and shell scripts required to run the application from Windows or Unix.

Before you run the application, you have to create the Derby database. Just run the included derby-create.sh or derby-create.bat script to do so, it will create two directories called users1 and users2. Then you can start the demo by either running run_api.sh or run_api.bat for the API version, run_rl.sh or run_rl.bat for the Resource Loader version.

Here is the list of JAR files with version required to run this demo. They're all included in the downloadable ZIP file.