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JDBC pools configuration

BTM XA datasources can be created via some java code or via a BTM-specific tool called the Resource Loader. You are free to choose the method you prefer, there is absolutely no difference between them.

Using code

BTM comes bundled with a JDBC XA connection pool. It is very easy to configure it. You basically have to create an instance of [bitronix.tm.resource.jdbc.PoolingDataSource set some properties and you're done.

Here is an example of datasource creation that connects to an Oracle database:

1. The Bitronix PoolingDataSource is a javabean that implements java.sql.DataSource.
2. You have to specify the driver's XADataSource implementation here.
3. Each datasource must be assigned a unique name. This is required for distributed crash recovery.
4. This datasource will pool 5 connections.
5. You have to set allowLocalTransactions to true if you want to be able to run SQL statements outside of XA transactions scope.
6,7,8. The driverProperties is a java.util.Properties object. You have to add into it a set of property name / property value of the OracleXADataSource class. You have to refer to the driver's documentation to know what can / has to be set. The OracleXADataSource javadoc contains this list for the Oracle case. BTM will perform conversion from String to boolean or to int when necessary.
9,10. You can now use the PoolingDataSource like any other java.sql.DataSource.
11. Remember to close the PoolingDataSource after you're done with it to release the connections.

No XADataSource implementation ?

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If your database vendor does not provide a XADataSource implementation, you should have a look at the Last Resource Commit optimization.

Eager initialization

The connection pool will be initialized during the first call to getConnection(). It might be desirable to initialize the pool eagerly, like during application startup rather than having to wait for the first requests. This can be done by calling init():

Now line 9 will initialize the pool and create the 5 connections to the database instead of line 10.

Using the Resource Loader

A datasource configuration utility is also bundled with BTM. It is convenient to use it rather than create your datasources in code. Refer to the Resource Loader page for more details.

Here is the equivalent Resource Loader configuration of the previous code example:

Eager initialization

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The Resource Loader will always eager initialize the created datasources.

You just have to write those properties in a simple text file and tell BTM where to load it by setting the resourceConfigurationFilename property of the Configuration object.

Now you also have to know how to get the datasource created by the Resource Loader. There are multiple ways:

  • Add bitronix.tm.resource.bind=true to your resource loader properties file. The datasources will then be bound to the default JNDI server using their uniqueName as their JNDI name.
  • Another way is to bind the PoolingDataSource yourself or via some application server specific configuration. This is the approach used with Jetty.
  • Yet another way (in case the JNDI context is read only, like in Tomcat) is to bind a bitronix.tm.resource.ResourceFactory object, passing it a javax.naming.Reference containing a javax.naming.StringRefAddr containing the datasource's uniqueName as addrType somewhere in your JNDI tree. The bitronix.tm.resource.ResourceFactory class will just return the datasource with the specified uniqueName. This is explained more in-depth in the Tomcat integration page.
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