JMX publisher

Tool to get properties and methods published via JMX easily.

It consist of following annotations:

• @JMXProperty - annotates field OR method that should be visible through JMX. Method should have no parameters, it's result is returned.
• @JMXPropertyGetter - annotates method that serves as getter for specific field
• @JMXPropertySetter - annotates method that serves as setter for specific field
• @JMXOperation - annotates method (must be public) that servers as JMX operation

Usage is fairly simple - user annotates fields or method that he wants to show via JMX as @JMXProperty. As long as these fields are java types (no custom types), everything should work out of the box. There is no need to create getters for fields, methods marked as @JMXPropertyGetter are optional (however, return type must be compatible with property type). By the same logic, you can mark method as a @JMXProperty and its result will be published as it was an ordinary property - no need to create cover property.

Setters and getters can have names - this links them to the field. Field can have names too, if no name is specified, field name is used. If there is no name specified for setter/getter, framework tries to automatically resolve what property do these methods belong to - stripping get/is/set prefix and lowercasing first letter. See example below.

Finally, there is the MyDynamicBean class that processes annotations and exposes JMX properties. Just like this:

ClassWithJMXProperties obj = new ClassWithJMXProperties();
...
...
MyDynamicBean.exposeAndRegisterSilently(obj);//expose JMX

Larger Example:

public class TestMonitorable {

    private static final Logger LOGGER = LoggerFactory.getLogger(TestMonitorable.class);

    @JMXProperty(setable = true)
    private long primitiveCnt = 0L;
    @JMXProperty
    private AtomicInteger atomicCnt = new AtomicInteger(0);
    @JMXProperty
    private AtomicInteger atomicCntSetable = new AtomicInteger(0);
    @JMXProperty
    private Map<String, Long> mapStats = new HashMap<String, Long>();

    public static void main(String[] args) throws Exception {
        TestMonitorable tm = new TestMonitorable();
        tm.testMonitorable();
    }

    @JMXProperty(name="cacheSize")
    public long getCacheSize() {
        return mapStats.size();
    }

    @JMXPropertySetter
    public void setPrimitiveCnt(long num) {
        LOGGER.debug("Set method invoked");
        primitiveCnt = num;
    }

    @JMXPropertyGetter
    public long getPrimitiveCnt() {
        LOGGER.debug("Get method invoked");
        return primitiveCnt;
    }

    @JMXOperation
    public void jmxOperationTest(String param) {
        System.out.println("This is @JMXOperation, called with parameter "+param);
    }

    public void testMonitorable() throws Exception {
        //can be called like that, or simplier: MyDynamicBean.exposeAndRegisterSilently(this);
        MyDynamicBean mdb = new MyDynamicBean(this);
        mdb.register();
        Thread.sleep(Long.MAX_VALUE);
    }

• As setable can be used properties of following types: int, long, boolean, Integer, Long, Boolean, String, AtomicInteger, AtomicLong and AtomicBoolean
• The atomic types looks like its basic class, e.g. AtomicInteger is shown like it was an ordinary Integer (see example usage below).

#JMX client

JMXClientConnection class provides a good way to access the JMX properties (and operations) directly from Java/Scala program.

Small example of usage (snippet from tests):

  JMXClientConnection connection = new JMXClientConnection("localhost:9969");
  ObjectName objectName = connection.getObjectName("com.avast.jmx:type=JmxTestApplication");

  int valueInt = new Random().nextInt();
  connection.setAttribute(objectName, "setableInt", valueInt);
  connection.setAttribute(objectName, "setableInteger", valueInt);

  assertEquals(valueInt, connection.getAttribute(objectName, "setableInt"));
  assertEquals(valueInt, connection.getAttribute(objectName, "setableInteger"));

or (Scala):

  val jmx = new JMXClientConnection(URL_JMX, PORT_JMX)

  val o = jmx.getObjectName("com.avast.sb.plugins:type=WinQualPlugin")

  assert(o != null)

  val oldVal = jmx.getAttribute(o, "dumpPercentage")

  jmx.invoke(o, "setDumpPercentage", Array(1.0.asInstanceOf[AnyRef]), Array(JMXClientConnection.JAVA_DOUBLE_TYPE))

Unfortunately, method invoking requires exact parameter typing (or the method would not be found by reflection).

Atomic properties usage:

  connection.setAttribute(objectName, "setableAtomicInteger", valueInt);
  assertEquals(valueInt, connection.getAttribute(objectName, "setableAtomicInteger"));

Just like and ordinary Integer...