Transactions

Overview

This example will show you how to leverage the JTA transaction manager provided by Fuse ESB when working with JMS or JTA Camel endpoints. We will setup a route that reads messages from a queue and inserts information into a database using JTA and deploy that onto Fuse ESB 7.1.

What You Will Learn

In studying this example you will learn:

• how to set up an XA-aware DataSource
• how to configure a JTA persistence unit
• how to define a transactional route
• how to leverage Fuse ESB's JTA and JPA support in your routes

Prerequisites

Before building and running this example you need:

• Maven 3.0.4 or higher
• JDK 1.6
• Fuse ESB Enterprise 7.1
• Apache Derby 10.9.1.0 or higher

Files in the Example

• pom.xml - the Maven POM file for building the example
• database - contains the persistence unit definition and the JPA entity beans
• datasource - contains the JDBC data source definition
• features - contains the Apache Karaf features definition that allows for easy installation of this example
• routing - contains the transactional Camel routes

For more information about these Maven modules, have a look at the README.md file in every module directory.

Setting up the database server

For this example, we will be using Apache Derby as our database server. Before installing the demo, we need to set up the server and create the database tables we will be using.

We will refer to the directory that contains your Apache Derby installation as DERBY_HOME

Start the network server

Start Apache Derby's network server with

• on Linux/Unix/MacOS: DERBY_HOME/bin/startNetworkServer.sh
• on Windows: DERBY_HOME\bin\startNetworkServer.bat

Create the database tables

Open Derby's interactive shell:

• on Linux/Unix/MacOS: DERBY_HOME/ij.sh
• on Windows: DERBY_HOME\ij.bat

In the shell, run these two commands:

ij> connect 'jdbc:derby://localhost:1527/transactions;create=true';
ij> CREATE TABLE flights (
      number VARCHAR(12) NOT NULL,
      departure VARCHAR(3),
      arrival VARCHAR(3),
      PRIMARY KEY (number)
    );

To be sure the tables got created successfully, run one more command:

ij> select * from flights;

If the latter command shows you the empty table you just created, you're ready to move along with this demo. Leave ij running for now, we will use it again later to verify that our messages are being processed correctly.

Building the Example

In the directory where this README.md file is found, run mvn clean install to build the example.

Running the Example

We will refer to the directory that contains your Fuse ESB installation as $ESB_HOME.

Configuring additional users

Before we can start Fuse ESB, we have to make sure we configure a user we can use later on to connect to the embedded message broker and send messages to a queue. Edit the $ESB_HOME/etc/users.properties file and add a line that says:

user=password,admin

The syntax for this line is <userid>=<password>,<group>, so we're creating a user called user with a password password who's a member of the admin group.

Start Fuse ESB

Start Fuse ESB with

• on Linux/Unix/MacOS: bin/fuseesb
• on Windows: bin\fuseesb.bat

Adding the features repository

To allow for easy installation of the example, we created a features descriptor. On Fuse ESB's console, add the extra features repository with this command:

FuseESB:karaf@root> features:addurl mvn:org.fusesource.example.transactions/features/1.0-SNAPSHOT/xml/features

Install the example using the feature

First, install the feature itself using this command:

FuseESB:karaf@root> features:install transactions-openjpa-demo

Using osgi:list in the console, you should now see this demo's bundles at the bottom of the list.

Using jconsole to send JMS messages

Open jconsole and connect to the running Fuse ESB Enterprise instance. If the instance is running locally, connect to the process called org.apache.karaf.main.Main.

On the MBeans tab, navigate to org.apache.activemq → fusemq → Queue → Input.Flights. Send a few messages to the queue using the sendTextMessage(String body, String user, String password) operation. For the second and third password, use the username and password you configured earlier. The first parameter will become the flight ID in the database, so just use your imagination for that one ;)

Verifying the result

Now, head back to ij and run this SQL query:

ij> select * from flights;

You will see new database rows for every message you sent, using the message body as the flight number.

More information

For more information see:

• Fuse ESB Enterprise 7.1 - EIP Transaction Guide (registration required)