See attached code pls, When lastTime var is not null?

[handdola]

public static class AnalyzeVisits extends CascalogBuffer {
    private static final int VISIT_LENGTH_SECS = 60 * 15;

    public void operate(FlowProcess process, BufferCall call) {
        Iterator<TupleEntry> it = call.getArgumentsIterator();
        int bounces = 0;
        int visits = 0;
       Integer lastTime = null;                       <- lastTime initialized
        int numInCurrVisit = 0;
        while(it.hasNext()) {
            TupleEntry tuple = it.next();
            int timeSecs = tuple.getInteger(0);
            if(lastTime == null ||
                    (timeSecs - lastTime) > VISIT_LENGTH_SECS) {    <-- ??? when lastTime updated
                visits++;
                if(numInCurrVisit == 1) {
                    bounces++;
                }
                numInCurrVisit = 0;
            }
            numInCurrVisit++;
        }
        if(numInCurrVisit==1) {
            bounces++;
        }
        call.getOutputCollector().add(new Tuple(visits, bounces));
    }
}