The Java code for this recipe is located in the org.camelcookbook.monitoring.monitor package. The Spring XML files are located under src/main/resources/META-INF/spring and prefixed with monitor.

This recipe's instructions assume that we are monitoring an existing Camel route with an id of "monitorRoute". It does not matter which DSL, XML, or Java, that route is written in, or even what that route does since we are monitoring the number of exchanges (messages) that are processed by that route. This will create an MBean with the following name that we will monitor:

org.apache.camel:context=localhost/camel-1,type=routes,name="monitorRoute"

The following is the Java DSL version of a route used in the provided example code:

from("direct:start")
    .routeId("monitorRoute")
  .transform(simple("Monitoring ${body}"))
  .log("${body}")
  .to("mock:result");

This recipe assumes that you have JMX enabled and configured within your Camel route. See the Configuring JMX recipe for more details.

Create a Camel route that consumes from the Camel JMX endpoint that is configured with the coordinates for the JMX MBean from which you want to gather data.

The Camel JMX Component is used in this recipe to do two things: create a JMX Notification consumer, and create a Monitor bean to send JMX Notifications.

The URI format to set up the Camel JMX Component to consume JMX Notifications from the in-process platform MBean server is as follows:

jmx://platform?options

To connect to a remote MBean server, you would specify the URI as follows:

jmx:service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi?options

To specify the ObjectName composed of multiple properties, you use the following syntax where the ObjectName property name is prefixed with "key." and followed by its value. For example, to monitor an MBean with the ObjectName property:

org.apache.camel:name=simpleBean

You specify the following URI:

jmx:platform?objectDomain=org.apache.camel             &key.name=simpleBean

The second thing that the Camel JMX Component can do for us is to create a local Monitor bean that will generate JMX Notifications based on change rules we specify.

For example, to generate a Notification every time the value of the MonitorNumber JMX attribute changes, we could use the following URI:

jmx:platform?objectDomain=org.apache.camel&key.name=simpleBean&monitorType=counter&observedAttribute=MonitorNumber&initThreshold=1&granularityPeriod=500

Under the covers, the Camel JMX Component will access the JMX API similar to the following example:

CounterMonitor monitor = 
    new CounterMonitor(); // javax.management.monitor
monitor.addObservedObject(makeObjectName("simpleBean"));
monitor.setObservedAttribute("MonitorNumber");
monitor.setNotify(true);
monitor.setInitThreshold(1);
monitor.setGranularityPeriod(500);
registerBean(monitor, makeObjectName("counter"));
monitor.start();

In general, you would use the existing JMX aware tools to manage and monitor your Camel routes. The Camel JMX Component is useful in cases where you either can't use a conventional monitoring tool, such as when monitoring systems remotely over constrained network connections, or when you need a more do-it-yourself, custom approach.

The Camel JMX Component generates an XML or Java object that can be processed in subsequent route steps. This allows you to take local action based on the value of the Notification, thereby acting as a lightweight monitoring alert system. It also allows you to aggregate and summarize this data for rebroadcast on other channels, such as summarizing a number of monitored attributes, and periodically publishing on JMS or HTTP to some remote non-JMX listener. This provides you with some extra tools to create a smart agent that can monitor your code, and react to changing conditions—all using Camel.