语法

create context context_name start start_condition end end_condition

如：

// 9点到17点此context才可用（以引擎的时间为准）。如果事件进入的事件不在此范围内，则不受该context影响create context NineToFive start (0, 9, *, *, *) end (0, 17, *, *, *)

 

例子

import com.espertech.esper.client.*;/** * @author yaoyuan2 * @date 2019/3/26 */public class NoOverLappingContextTest {    public static void main(String[] args) {        EPServiceProvider epService = EPServiceProviderManager.getDefaultProvider();        EPAdministrator admin = epService.getEPAdministrator();        EPRuntime runtime = epService.getEPRuntime();        String start = StartEvent.class.getName();        String end = EndEvent.class.getName();        String other = OtherEvent.class.getName();        // 以StartEvent事件作为开始条件，EndEvent事件作为结束条件        String epl1 = "create context NoOverLapping start " + start + " end " + end;        String epl2 = "context NoOverLapping select * from " + other;        admin.createEPL(epl1);        EPStatement state = admin.createEPL(epl2);        state.addListener(new UpdateListener() {            @Override            public void update(EventBean[] newEvents, EventBean[] oldEvents) {                if (newEvents != null) {                    EventBean event = newEvents[0];                    System.out.println("Class:" + event.getUnderlying().getClass().getName() + ", id:" + event.get("id"));                }            }        });        StartEvent s = new StartEvent();        System.out.println("sendEvent: StartEvent");        runtime.sendEvent(s);        OtherEvent o = new OtherEvent();        o.setId(2);        System.out.println("sendEvent: OtherEvent");        runtime.sendEvent(o);        EndEvent e = new EndEvent();        System.out.println("sendEvent: EndEvent");        runtime.sendEvent(e);        OtherEvent o2 = new OtherEvent();        o2.setId(4);        System.out.println("sendEvent: OtherEvent");        runtime.sendEvent(o2);    }}class StartEvent{}class EndEvent{}class OtherEvent{    private int id;    public int getId()    {        return id;    }    public void setId(int id)    {        this.id = id;    }}

输出

sendEvent: StartEventsendEvent: OtherEventClass:com.ebc.NoOverLappingContext.OtherEvent, id:2sendEvent: EndEventsendEvent: OtherEvent

由此看出，在NoOverLapping这个Context下监控OtherEvent，必须是在StartEvent被触发才能监控到，所以在EndEvent发送后，再发送一个OtherEvent是不会触发Listener的。