com.hazelcast.internal.metrics

Annotation Type Probe

@Retention(value=RUNTIME)
 @Target(value={FIELD,METHOD})
public @interface Probe

Annotation that can be placed on a field or a method of an object to indicate that it should be tracked by the MetricsRegistry when the MetricsRegistry.scanAndRegister(Object, String) is called.

The MetricsRegistry will automatically scan all interfaces and super classes of an object (recursively). So it is possible to define a Probe on e.g. an interface or an abstract class.

Prefer field

Prefer placing the Probe to a field rather than to a method if the type is primitive. The Field provides access to the actual field without the need for autoboxing. With the Method a wrapper object is created when a primitive is returned by the method. Therefore, fields produce less garbage than methods.

A Probe can be placed on fields or methods with the following (return) type:

1. byte
2. short
3. int
4. float
5. long
6. double
7. AtomicInteger
8. AtomicLong
9. Counter
10. Byte
11. Short
12. Integer
13. Float
14. Double
15. Collection: it will return the size
16. Map: it will return the size
17. Semaphore: it will return the number of available permits

If the field or method points to a null reference, it is interpreted as 0.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
ProbeLevel	level Returns the ProbeLevel.
String	name The name of the Probe.
ProbeUnit	unit Measurement unit of a Probe.

Element Detail

name

public abstract String name

The name of the Probe. By default the name of the field or method is used.

Returns:

the name of the Probe.

Default:

""

level

public abstract ProbeLevel level

Returns the ProbeLevel. Using ProbeLevel one can indicate how 'important' this Probe is. This is useful to reduce memory overhead due to tracking of probes.

Returns:

the ProbeLevel.

Default:

com.hazelcast.internal.metrics.ProbeLevel.INFO

unit

public abstract ProbeUnit unit

Measurement unit of a Probe. Not used on member, becomes a part of the key.

Default:

com.hazelcast.internal.metrics.ProbeUnit.COUNT