JMX support

Every Config object created by OWNER is also a Dynamic MBean: you can register it on an MBeanServer and inspect or modify your configuration at runtime with any JMX client, such as JConsole or VisualVM.

There is nothing to enable: just register the config instance on the MBean server of your choice.

public interface MyConfig extends Mutable, Reloadable {
    @Key("server.port.number")
    @DefaultValue("80")
    int port();

    @Key("server.host.name")
    @DefaultValue("localhost")
    String hostname();
}

MyConfig cfg = ConfigFactory.create(MyConfig.class);

MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
mbs.registerMBean(cfg, new ObjectName("org.aeonbits.owner:type=configuration,name=MyConfig"));

What the MBean exposes

• Attributes: one per property, named after the property key (for instance server.port.number). Attributes are exposed as strings and are both readable and writable: setting an attribute updates the configuration exactly like a setProperty() call on a Mutable config.
• Operations:
  • getProperty(key) — gets the value for a property;
  • setProperty(key, value) — sets the value for a property;
  • reload() — reloads the configuration, like a reload() call on a Reloadable config.

Changes performed through JMX act on the live configuration object: the next call to a config method will return the updated value. Combined with the event support, this lets your application react immediately to changes applied from a JMX console:

cfg.addPropertyChangeListener(new PropertyChangeListener() {
    public void propertyChange(PropertyChangeEvent evt) {
        System.out.printf("property %s changed from %s to %s%n",
                evt.getPropertyName(), evt.getOldValue(), evt.getNewValue());
    }
});

A runnable demo is available in JMXExample on GitHub: launch it, attach JConsole to the process, and play with the attributes and operations of the org.aeonbits.owner:type=configuration,name=MyConfig MBean.

Same instance, multiple names

The same config instance can be registered on the MBean server under multiple object names; all the registrations act on the same underlying configuration.