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How to use BTM as the transaction manager in Tomcat 6.x

These instructions have been verified against BTM 2.1.0.

Contents

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Step 1: Copy the BTM jars

Copy the following jars from the BTM distribution to the Tomcat lib/ directory:

  • btm-2.0.1.jar
  • jta-1.1.jar
  • slf4j-api-1.6.0.jar
  • slf4j-jdk14-1.6.0.jar
  • btm-tomcat55-lifecycle-2.1.0.jar (it works with both Tomcat 5.5 and Tomcat 6)

You will also need to copy your JDBC driver's JAR file in that same folder. In this example, we've used Derby 10.3.2.1 so we copied derby.jar in Tomcat's lib/ directory.

Step 2: Configure BTM as the transaction manager

Windows: Create a file named setenv.bat with the following commands under Tomcat's bin/ directory:

Code Block
set CATALINA_OPTS=-Dbtm.root=%CATALINA_HOME% -Dbitronix.tm.configuration=%CATALINA_HOME%\conf\btm-config.properties

Unix: Create a file named setenv.sh with the following commands under Tomcat's bin/ directory:

Code Block
CATALINA_OPTS="-Dbtm.root=$CATALINA_HOME -Dbitronix.tm.configuration=$CATALINA_HOME/conf/btm-config.properties"

Now create a file named btm-config.properties with the following properties under Tomcat's conf/ directory:

Code Block
bitronix.tm.serverId=tomcat-btm-node0
bitronix.tm.journal.disk.logPart1Filename=${btm.root}/work/btm1.tlog
bitronix.tm.journal.disk.logPart2Filename=${btm.root}/work/btm2.tlog
bitronix.tm.resource.configuration=${btm.root}/conf/resources.properties

Then edit the file named server.xml under Tomcat's conf/ directory. Under this line:

Code Block
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />

add this one:

Code Block
<Listener className="bitronix.tm.integration.tomcat55.BTMLifecycleListener" />

The <Listener> tag will make sure BTM is started when Tomcat starts up and shutdown when Tomcat shuts down.

The next step is to edit the file named context.xml under Tomcat's conf/ directory. Under this line:

Code Block
<WatchedResource>WEB-INF/web.xml</WatchedResource>

add this one:

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<Transaction factory="bitronix.tm.BitronixUserTransactionObjectFactory" />

The <Transaction> tag will bind the transaction manager at the standard JNDI location java:comp/UserTransaction.

Finally, create an empty file named resources.properties under Tomcat's conf/ directory.

Step 3: Configure datasources that are transaction aware

You have to put your datasources configurations in Tomcat's conf/resources.properties file. Here's an example of using BTM with a DataSource that implements javax.sql.XADataSource:

Code Block
resource.ds1.className=org.apache.derby.jdbc.EmbeddedXADataSource
resource.ds1.uniqueName=jdbc/mydatasource
resource.ds1.minPoolSize=0
resource.ds1.maxPoolSize=5
resource.ds1.driverProperties.databaseName=../work/db1
resource.ds1.driverProperties.createDatabase=create

This will create a bitronix.tm.resource.jdbc.PoolingDataSource that implements javax.sql.DataSource and interacts with the javax.sql.XADataSource provided in this instance by Derby.

If your database vendor does not provide an XADataSource, you can use BTM's bitronix.tm.resource.jdbc.lrc.LrcXADataSource as the XADataSource to allow your database connections to be controlled by the transaction manager:

Code Block
resource.ds2.className=bitronix.tm.resource.jdbc.lrc.LrcXADataSource
resource.ds2.uniqueName=jdbc/exampleNonXADS
resource.ds2.minPoolSize=0
resource.ds2.maxPoolSize=5
resource.ds2.driverProperties.driverClassName=org.apache.derby.jdbc.EmbeddedDriver
resource.ds2.driverProperties.url=jdbc:derby:../work/db2;create=true

Again, we've used Derby as an example, but as the LrcXADataSource uses only the class name and url of a java.sql.Driver, you can use it with any database providing a JDBC driver.

Step 4: Configure transaction manager and datasources initialization in your META-INF/context.xml

In the web application where you want one or more datasource to be used, you have to create a META-INF/context.xml file.

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XML
XML
<Context>

    <Resource name="jdbc/mydatasource" auth="Container" type="javax.sql.DataSource"
        factory="bitronix.tm.resource.ResourceObjectFactory" uniqueName="jdbc/mydatasource" />

    <Resource name="jdbc/exampleNonXADS" auth="Container" type="javax.sql.DataSource"
        factory="bitronix.tm.resource.ResourceObjectFactory" uniqueName="jdbc/exampleNonXADS" />

</Context>

The <Resource> tags will bind a bitronix.tm.resource.ResourceObjectFactory object each, passing it a javax.naming.Reference containing a javax.naming.StringRefAddr containing the datasource's uniqueName as addrType.

Info
titleTomcat specific

This mechanism is internal to Tomcat. You do not have to worry about how it works, the bitronix.tm.resource.ResourceObjectFactory class will handle those details.

The bitronix.tm.resource.ResourceObjectFactory class will return the datasource previously configured in in Tomcat's conf/resources.properties with the specified uniqueName when it is fetched from JNDI.

Step 5: Configure datasources references in your web.xml

Before your code can access configured datasources via JNDI ENC URLs, you need to declare resource references in your web.xml:

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XML
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
 <!DOCTYPE web-app PUBLIC
	"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
	"http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
  <resource-env-ref>
    <resource-env-ref-name>jdbc/mydatasource</resource-env-ref-name>
    <resource-env-ref-type>javax.sql.DataSource</resource-env-ref-type>
  </resource-env-ref>

  <resource-env-ref>
    <resource-env-ref-name>jdbc/exampleNonXADS</resource-env-ref-name>
    <resource-env-ref-type>javax.sql.DataSource</resource-env-ref-type>
  </resource-env-ref>
</web-app>

Now you can do JNDI lookups on those URLs to access the configured datasources:

Code Block
DataSource exampleNonXADS = (DataSource) ctx.lookup("java:comp/env/jdbc/exampleNonXADS");
DataSource mydatasource = (DataSource) ctx.lookup("java:comp/env/jdbc/mydatasource");

and you can do JNDI lookups on this URL to access the transaction manager:

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UserTransaction ut = (UserTransaction) ctx.lookup("java:comp/UserTransaction");