JarCastingJMX 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...
