NMR

NMR Component

The nmr component is an adapter to the Normalized Message Router (NMR) in ServiceMix, which is intended for use by Camel applications deployed directly into the OSGi container. By contrast, the JBI component is intended for use by Camel applications deployed into the ServiceMix JBI container.

Installing

The NMR component is provided with Apache ServiceMix. It is not distributed with Camel. To install the NMR component in ServiceMix, enter the following command in the ServiceMix console window:

features install nmr

You also need to instantiate the NMR component. You can do this by editing your Spring configuration file, META-INF/spring/*.xml, and adding the following bean instance:

<beans xmlns:osgi="http://www.springframework.org/schema/osgi" ... >
    ...
    <bean id="nmr" class="org.apache.servicemix.camel.nmr.ServiceMixComponent">
        <property name="nmr">
            <osgi:reference interface="org.apache.servicemix.nmr.api.NMR" />
        </property>
    </bean>
    ...
</beans>

NMR consumer and producer endpoints

The following code:

from("nmr:endpoint:http://foo.bar.org/MyService/MyEndpoint")

Automatically exposes a new endpoint to the bus, where the service QName is {http://foo.bar.org}MyService and the endpoint name is MyEndpoint (see #URI-format).

When an NMR endpoint appears at the end of a route, for example:

to("nmr:endpoint:http://foo.bar.org/MyService/MyEndpoint")

The messages sent by this producer endpoint are sent to the already deployed JBI endpoint.

URI format

nmr:service:serviceNamespace[sep]serviceName
nmr:endpoint:serviceNamespace[sep]serviceName[sep]endpointName
nmr:name:endpointName

The separator that should be used in the endpoint URL is:

/ (forward slash), if serviceNamespace starts with http://, or
: (colon), if serviceNamespace starts with urn:foo:bar.

For more details of valid NMR URIs see the ServiceMix URI Guide.

Using the nmr:service: or nmr:endpoint: URI formats sets the service QName on the JBI endpoint to the one specified. Otherwise, the default Camel JBI Service QName is used, which is:

{http://activemq.apache.org/camel/schema/jbi}endpoint

Examples

nmr:service:http://foo.bar.org/MyService
nmr:endpoint:urn:foo:bar:MyService:MyEndpoint
nmr:endpoint:http://foo.bar.org/MyService/MyEndpoint
nmr:name:cheese

Using Stream bodies

If you are using a stream type as the message body, you should be aware that a stream is only capable of being read once. So if you enable DEBUG logging, the body is usually logged and thus read. To deal with this, Camel has a streamCaching option that can cache the stream, enabling you to read it multiple times.

from("jbi:endpoint:http://foo.bar.org/MyService/MyEndpoint").streamCaching().to("xslt:transform.xsl", "bean:doSomething");

From Camel 1.5 onwards, the stream caching is default enabled, so it is not necessary to set the streamCaching() option.
In Camel 2.0 we store big input streams (by default, over 64K) in a temp file using CachedOutputStream. When you close the input stream, the temp file will be deleted.

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