@Override
    public void init(TriggerDefinition triggerDefinition, SiddhiAppContext siddhiAppContext, StreamJunction
            streamJunction) {
        this.triggerDefinition = triggerDefinition;
        this.siddhiAppContext = siddhiAppContext;
        this.streamJunction = streamJunction;
        if (siddhiAppContext.getStatisticsManager() != null) {
            this.throughputTracker = QueryParserHelper.createThroughputTracker(siddhiAppContext,
                    triggerDefinition.getId(),
                    SiddhiConstants.METRIC_INFIX_TRIGGERS, null);
        }
    }
Implementation of {@link Trigger} which will trigger events based on a pre-defined period.
modules/siddhi-core/src/main/java/io/siddhi/core/trigger/PeriodicTrigger.java