Metric Collector SPI. This is a class instead of interface so in case of
adding new methods in the future we can do that safetly without breaking
any existing clients that implements this SPI.
Can be used to serve as a factory for the request metric collector.
Returns an instance of the collector; or null if if failed to create
Starts the request metric collector.
- true if the collector is successfully started; false otherwise.
public abstract boolean start();
Stops the request metric collector.
- true if the collector is successfully stopped; false if the
collector is not running and therefore the call has no effect.
public abstract boolean stop();
Returns true if this collector is enabled; false otherwise.
A convenient instance of a no-op request metric collector.