Timer.java

/* trimmed down and reformatted for blog, see cassandra repo for actual code */
public final class Timer {
    private Histogram responseTime = new Histogram(3);
    private Histogram serviceTime = new Histogram(3);
    private Histogram waitTime = new Histogram(3);
    private long intendedTimeNs;
    private long startTimeNs;
    private long endTimeNs;
    
    public void intendedTimeNs(long v) {
        intendedTimeNs = v;
    }

    public void start() {
        startTimeNs = System.nanoTime();
    }

    public void stop(long partitionCount, long rowCount, boolean error) {
        endTimeNs = System.nanoTime();
        serviceTime.recordValue(endTimeNs - startTimeNs);
        
        if (intendedTimeNs != 0) { // if intended time is set we can compute response/wait
            responseTime.recordValue(endTimeNs - intendedTimeNs);
            waitTime.recordValue(startTimeNs - intendedTimeNs);
        }
        
        intendedTimeNs = startTimeNs = endTimeNs = 0;
    }
}