There are some configuration tasks that must usually be done when developing real-world services:

• Configuring JDBC drivers
• Configuring transports
• Configuring message formatters and message builders

This is a mandatory configuration task when using data services. JDBC drivers allow WSO2 EI to connect to databases. By default, there are many JDBC drivers installed, so we have to configure the drivers' need for connecting the data sources that will provide us with the data in the orchestration.

We can do that with these simple steps:

1. Locating the correct JDBC drivers for the databases that will play in our orchestration.
2. Copying them to the <EI_HOME>/lib/ folder.
3. Restarting the server.

Once the server is restarted, we will be able to connect to the databases.

WSO2 EI supports several transports that we can use when building our services, such as the following:

• JMS transport: This enables sending and receiving messages to queues and topics that implement the JMS specification
• Mailto transport: This enables sending emails
• VFS transport: Virtual File System (VFS) transport allows us to process files in a directory of the filesystem

We can enable this transport and many others in the <EI_HOME>/conf/axis2/axis2.xml file. All the transports available can be found in that file with a default configuration. We have to configure these transports for input and output connections. The input transports are configured using the transportReceiver XML tag, while the output transports are configured with the transportSender tag:

<transportSender name="jms" class="org.apache.axis2.transport.jms.JMSSender"/>
 
<transportReceiver name="jms" class="org.apache.axis2.transport.jms.JMSListener">
<parameter name="myTopicConnectionFactory" locked="false">
<parameter name="java.naming.factory.initial" locked="false">org.wso2.andes.jndi.PropertiesFileInitialContextFactory</parameter>
<parameter name="java.naming.provider.url" locked="false">conf/jndi.properties</parameter>
<parameter name="transport.jms.ConnectionFactoryJNDIName" locked="false">TopicConnectionFactory</parameter>
<parameter name="transport.jms.ConnectionFactoryType" locked="false">topic</parameter>
</parameter>
 
<parameter name="myQueueConnectionFactory" locked="false">
<parameter name="java.naming.factory.initial" locked="false">org.wso2.andes.jndi.PropertiesFileInitialContextFactory</parameter>
<parameter name="java.naming.provider.url" locked="false">conf/jndi.properties</parameter>
<parameter name="transport.jms.ConnectionFactoryJNDIName" locked="false">QueueConnectionFactory</parameter>
<parameter name="transport.jms.ConnectionFactoryType" locked="false">queue</parameter>
</parameter>
 
<parameter name="default" locked="false">
<parameter name="java.naming.factory.initial" locked="false">org.wso2.andes.jndi.PropertiesFileInitialContextFactory</parameter>
<parameter name="java.naming.provider.url" locked="false">conf/jndi.properties</parameter>
<parameter name="transport.jms.ConnectionFactoryJNDIName" locked="false">QueueConnectionFactory</parameter>
<parameter name="transport.jms.ConnectionFactoryType" locked="false">queue</parameter>
</parameter>
</transportReceiver>

Message formatters and Message builders are the components that allow us to send and receive different types of messages according to the content type specified in the request. It is important to enable the content type used in the messages exchanged because if the content type received is not configured in the system, the message will not be understood.

Message builders are used to process incoming messages, and Message formatters are used to build the outgoing messages.

We can enable the Message formatters and builders in the file located in <EI_HOME>/conf/axis2/axis2.xml. Message formatters are under the same name in XML tag, and so are Message builders. Most values that messages content type can be received are already configured, but they are commented. We just have to find the one we need and uncomment it for Message formatters and/or message builders, depending on the case.

For example, to enable us to send and receive JSON messages, we have to enable that content type for input and output messages in axis2.xml:

<messageFormattercontentType="application/json" class="org.wso2.carbon.integrator.core.json.JsonStreamFormatter"/>
 
<messageBuildercontentType="application/json" class="org.wso2.carbon.integrator.core.json.JsonStreamBuilder"/>