Tag Archives: DSL

Feb 19 2013
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Route a message to MongoDB

The requirement is very simple. Route an XML message from rabbitMQ to MongoDB. MongoDB BSON as the data storage and network transfer format for “documents”. BSON is a binary-encoded serialization of JSON-like documents. So, the source message is in a XML format, after getting it from rabbitMQ is necessary to translate into a JSON format compatible with MongoDB.

To translate a message from XML to JSON is possible to use Marshalling function available in Camel extension XmlJson. The pom.xml file needs this new entry:

<dependency>
	<groupId>org.apache.camel</groupId>
	<artifactId>camel-xmljson</artifactId>
	<version>${org.camel.version}</version>
</dependency>

Of course, to send communicate with MongoDB another entry has to be added to pom.xml:

<dependency>
	<groupId>org.apache.camel</groupId>
	<artifactId>camel-mongodb</artifactId>
	<version>${org.camel.version}</version>
</dependency>

Now, is possible to change the route on camel ApplicationContext file:

<!-- Camel route -->    
<camelContext xmlns="http://camel.apache.org/schema/spring">
	<dataFormats>
		<xmljson id="xmljson"/>
	</dataFormats>
	<route> 
		<from uri="spring-amqp:TPDirect:TPQueue:TPRouting?type=direct&amp;autodelete=true&amp;durable=true" />
		<marshal ref="xmljson"/>
		<log message="From XML to Json: DONE!" />
		<convertBodyTo type="java.lang.String"/>
		<to uri="mongodb:myDb?database=flights&amp;collection=tickets&amp;operation=save" />
	</route>                                 
</camelContext>
 
 
<!-- Mongo DB -->
<bean id="myDb" class="com.mongodb.Mongo">
	<constructor-arg index="0" value="localhost"/>
</bean>

Bean myDB contains the information to reach MongoDB. It’s also possible to define it using the full url:

<bean id="myDb" class="com.mongodb.Mongo"> 
    <constructor-arg index="0"> 
        <bean class="com.mongodb.MongoURI"> 
            <constructor-arg index="0" value="mongodb://username:password@host:port/db" /> 
        </bean> 
    </constructor-arg> 
</bean>

To avoid this exception:

Caused by: No type converter available to convert from type: byte[] to the required type: org.apache.camel.component.mongodb.converters.MongoDbBasicConverters with value

The JSON translated message has to be converted into String.

That’s all!

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